Some content of this application is unavailable at the moment.
If this situation persist, please contact us atFeedback&Contact
1. (WO2018081749) TRANSCUTANEOUS ANALYTE SENSOR SYSTEMS AND METHODS
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters
WHAT IS CLAIMED IS:

1. A sensor system for measuring an analyte concentration, the sensor system comprising:

a base having a distal side configured to face towards a skin of a host; a first adhesive coupled to the base and configured to couple the base to the skin; a transmitter coupled to the base and configured to transmit analyte measurement data;

a transcutaneous analyte measurement sensor coupled to the base; and a collapsible support member configured to resist non-axial forces of the sensor, the collapsible support member comprises a channel, and a portion of the sensor passes through the channel, wherein the channel is configured to resist a buckling force of the sensor as the sensor moves from the proximal position to the distal position.

2. The system of Claim 1 , wherein the collapsible support member is foam.

3. The system of Claim 2, wherein the portion of the sensor comprises a central axis, the channel is configured to resist lateral displacement of the portion of the sensor relative to the central axis, and the foam is configured to compress in response to the system moving the sensor from a proximal position to a distal position.

4. The system of Claim 1, wherein the base comprises a distal portion and a proximal portion, the system comprises a channel having walls configured to compress in response to the system moving the sensor from a proximal position to a distal position, the channel is located at least partially between the distal portion and the proximal portion of the base such that a portion of the sensor is located in the channel, and the walls of the channel are configured to resist lateral displacement of the portion of the sensor.

5. The system of Claim 4, wherein the walls comprise foam configured to compress in response to moving the proximal portion distally towards the distal portion of the base.

6. The system of Claim 5, wherein the walls comprise a proximal section having a first material, an intermediate section having a second material, and a distal section having a third material.

7. The system of Claim 6, wherein the second material is more rigid than the first and third materials such that the intermediate section is configured to resist the lateral displacement.

8. The system of Claim 7, wherein the second material is stiffer than the first and third materials such that the intermediate section is configured to resist the lateral displacement.

9. The system of any of Claims 7 or 8, wherein the second material is less compressible than the first and third materials.

10. The system of any of Claims 4-8, further comprising an interlock configured to secure the proximal portion of the base to the distal portion of the base in response to the system moving the sensor from the proximal position to the distal position.

11. The system of Claim 1, further comprising bellows coupled to the base, wherein at least a portion of the sensor is located in an interior area of the bellows.

12. The system of Claim 11, wherein the portion of the sensor comprises a central axis, the bellows are configured to resist lateral displacement of the portion relative to the central axis, and the bellows are configured to compress in response to the system moving the sensor from a proximal position to a distal position.

3. The system of Claim 12, further comprising an interlock coupled to the base and configured to secure the bellows in a compressed state.

14. The system of any of Claims 1 1 -13, further comprising a distal portion of the base and a proximal portion, wherein the bellows couple the distal portion to the proximal portion, the system further comprising a removable interference member located between the distal portion and the proximal portion such that the removable interference member is configured to block the system from moving the sensor from the proximal position to the distal position.

15. The system of any of Claims 1 -4 and 1 1-13, further comprising a tab coupled to the collapsible support member, wherein the system is configured such that actuating the tab causes the collapsible support member to collapse and causes at least a portion of the sensor to move distally relative to the base.

16. A sensor system for measuring an analyte concentration, the sensor system comprising:

a base having a distal side configured to face towards a skin of a host; a first adhesive coupled to the base and configured to couple the base to the skin; a transmitter coupled to the base and configured to transmit analyte measurement data;

a transcutaneous analyte measurement sensor coupled to the base; and

wherein the sensor is configured to be bent against the first adhesive or the base after removal of the base from the skin.

17. The system of Claim 16, wherein the base further comprises a first portion and a second portion, wherein the second portion of the base is coupled to the first portion of the base by a hinge configured such that decreasing a pivot angle between the first and second portions of the base places a portion of the sensor between the first and second portions of the base.

18. The system of Claim 17, wherein the hinge comprises a first pin rotatably coupled to a first channel configured to retain the first pm as the first portion of the base rotates relative to the second portion of the base.

19. The system of Claim 18, wherein the hinge comprises a second pm rotatably coupled to a second hole configured to retain the second pm as the first portion of the base rotates relative to the second portion of the base,

wherein the first pin protrudes in a first direction, the second pin protrudes in a second direction, and the first direction is opposite relative to the second direction.

20. The system of Claim 17, wherein the first adhesive comprises a first section and a second section, the first section is coupled to the first portion of the base such that the first section is configured to adhere the first portion of the base to the skin, and the second section is coupled to the second portion of the base such that the second section is configured to adhere the second portion of the base to the skin.

21. The system of Claim 20, wherein the hinge is configured to enable the first section of the first adhesive to face towards the second section of the first adhesive while the portion of the sensor is at least partially confined between the first and second portions of the base.

22. The system of any of Claims 17-21, wherein the system is configured to bend the portion of the sensor in response to rotating the hinge, wherein the portion of the sensor is bent between the first and second portions of the base to guard against a distal tip of the sensor penetrating tissue after the sensor system is removed from the skin.

23. The system of any of Claims 17-21, wherein the first portion of the base is rotationally spring-loaded relative to the second portion of the base such that the system is configured to decrease the pivot angle in response to a rotational spring bias.

24. The system of any of Claims 17-21, further comprising a torsion spring coupled to the hinge such that the torsion spring is configured to decrease the pivot angle to place the portion of the sensor between the first and second portions of the base.

25. The system of Claim 16, further an adhesive portion configured to bend at least a portion of the sensor towards the base, wherein a distal tip of the sensor is located between the base and the adhesive portion.

26. The system of Claim 25, further comprising an adhesive portion configured to collapse at least a portion of the sensor against the base.

27. The system of Claim 25, further comprising a sheet that covers a distal tip of the sensor and adheres to the first adhesive such that the sheet guards against the distal tip of the sensor penetrating tissue after the sensor system is removed from the skin.

28. The system of Claim 27, wherein the sheet is configured to be pliable.

29. The system of Claim 28, wherein the first adhesive couples the sheet to the base.

30. The system of Claim 28, wherein the sheet comprises a first state in which the sheet is folded, is located proximally relative to the distal tip, does not cover the distal tip, and forms a tab configured to enable a user to unfold the sheet.

31. The system of Claim 30, wherein the sheet comprises a second state in which the sheet is at least partially unfolded relative to the first state, is at least partially located distally relative to the distal tip, and the distal tip of the sensor is at least partially confined between the sheet and the first adhesive.

32. The system of Claim 27, wherein the sheet is a pliable sheet, the system further comprising a second sheet having a second puncture resistance that is greater than a first puncture resistance of the pliable sheet, wherein the second sheet is located between the distal tip and the pliable sheet to protect the pliable sheet from being punctured by the distal tip.

33. The system of Claim 32, wherein the first and second puncture resistances are measured using a distal tip of the sensor.

34. The system of any of Claims 32 or 33, wherein the second sheet is coupled to the pliable sheet such that the second sheet is configured to deform the distal tip as the pliable sheet is folded over the distal tip.

35. The system of Claim 16, wherein a distal tip of the sensor is at least partially confined between a pliable sheet and the base such that the pliable sheet holds at least a portion of the sensor in a bent position and the pliable sheet is adhered to the first adhesive.

36. The system of Claim 35, wherein the pliable sheet comprises a first state and a second state,

wherein in the first state, the pliable sheet is located proximally relative to the first adhesive when the sensor system is coupled to the skin, and

wherein in the second state, the pliable sheet is located distally relative to the first adhesive when the distal tip of the sensor is at least partially confined between the pliable sheet and the base.

37. A sensor system for measuring an anaiyte concentration, the sensor system comprising:

a base having a distal side configured to face towards a skin of a host;

a first adhesive coupled to the base and configured to couple the base to the skin;

a transmitter coupled to the base and configured to transmit anaiyte measurement data.; and

a transcutaneous anaiyte measurement sensor coupled to the base.

38. The system of Claim 37, wherein the base is configured to retract a distal tip of the sensor into an interior area of the base.

39. The system of Claim 38, further comprising a spring configured to retract the distal tip of the sensor into the interior area of the base.

40. The system of Claim 39, further comprising a latch, wherein the latch comprises a locked state configured to couple the transmitter to the base, and the latch comprises an unlocked state configured to enable removing the transmitter from the base.

41. The system of Claim 37, wherein the sensor system is configured to retract at least a portion of the sensor into a receptacle in response to removing the sensor system from the skin.

42. The system of Claim 37, wherein the sensor comprises a retractable distal tip.

43. The system of Claim 42, wherein the base comprises an interior area configured to receive the distal tip in response to a retraction of the distal tip.

44. The system of Claim 43, further comprising a spring coupled to the base and configured to retract the distal tip.

45. The system of Claim 37, further comprising a second adhesive coupled to the base and configured to bend a portion of the sensor against the base.

46. The system of Claim 37, wherein the sensor comprises a section located distally relative to the base, the section comprises a first portion and a second portion, the first portion of the sensor is configured to facilitate maintaining the second portion in a straight configuration during insertion of the section into the skin, and the first portion of the sensor is configured to soften in response to being located in vivo.

47. The system of Claim 46, wherein the first portion comprises a first buckling resistance prior to the insertion and a second buckling resistance after 48 hours of being located in vivo, wherein the second buckling resistance is less than the first buckling resistance.

48. The system of Claim 47, wherein the second buckling resistance is at least 30 percent less than the first buckling resistance.

49. The system of Claim 37, further comprising an arm slidably coupled to the base such that the arm is configured to at least one of retract a distal portion of the sensor and cover the distal portion of the sensor.

50. The system of Claim 37, further comprising a pull tab system having a pull tab, wherein the pull tab system is configured to retract the sensor in response to actuating the pull tab.

51. The system of Claim 37, further comprising a pull tab system having a pull tab, wherein the pull tab system is configured to retract the sensor in response to moving the pull tab relative to the base.

52. The system of any of Claims 50 or 51, wherein the pull tab system further comprises a first channel and an intermediate portion that couples the first channel to the pull tab, and

wherein the pull tab protrudes away from the base, a first portion of the sensor passes through the first channel, and the pull tab system is configured such that pulling the pull tab moves the first channel to retract the sensor.

53. The system of any of Claims 49-52, wherein the base comprises a second channel, wherein a second portion of the sensor passes through the second channel, and wherein the pull

tab system is configured such that pulling the pull tab retracts the sensor by pulling the second portion of the sensor out of the second channel and into an interior area of the sensor system.

54. The system of any of Claims 48-52, wherein the pull tab system is slidably coupled to the base such that the pull tab system is configured to slide in a first direction that is within plus or minus 45 degrees of being perpendicular to a proximal direction oriented away from the skin.

55. The system of Claim 54, wherein the transmitter is slidably coupled to the base such that the transmitter is configured to slide in a second direction that is within plus or minus 45 degrees of being perpendicular to the proximal direction.

56. The system of Claim 55, wherein the second direction is within plus or minus 45 degrees of being parallel to the first direction.

57. The system of Claim 37, further comprising a push button system having a push button, wherein the push button system is configured to retract the sensor in response to activating the button.

58. The system of Claim 57, wherein at least a portion of the push button system protrudes away from the base, and wherein the push button system is configured such that pressing the portion of the push button system into the base engages a sensor retraction feature that moves the sensor into an interior area of the sensor system.

59. The system of Claim 58, wherein the sensor retraction feature is at least one of a sensor retraction arm, a sensor retraction channel, and a sensor retraction hoop that pulls the sensor into the interior area of the sensor system.

60. The system of Claim 57, wherein the push button system further comprises a first arm and an intermediate portion that couples the first arm to the push button,

wherein the push button protrudes away from the base, a first portion of the sensor passes through a channel of the first arm, and the push button system is configured such that pushing the button moves the first arm to retract the sensor.

61. The system of Claim 57, wherein the push button system further comprises a first channel and an intermediate portion that couples the first channel to the push button,

wherein the push button protrudes away from the base, a first portion of the sensor passes through the first channel, and the push button system is configured such that pushing the button moves the first channel to retract the sensor.

62. The system of any of Claims 60 or 61, wherein the base comprises a second hole, wherein a second portion of the sensor passes through the second hole, and wherein the push button system is configured such that pushing the button retracts the sensor by pulling the second portion of the sensor out of the second hole and into an interior area of the sensor system by making a third portion of the sensor form at least one of a U-shape and a torturous shape.

63. The system of Claim 57, wherein the push button system is slidably coupled to the base such that the push button system is configured to slide in a first direction that is within plus or minus 45 degrees of being perpendicular to a proximal direction oriented away from the distal side of the base.

64. The system of Claim 63, wherein the transmitter is slidably coupled to the base such that the transmitter is configured to slide in a second direction that is within plus or minus 45 degrees of being perpendicular to the proximal direction.

65. The system of Claim 64, wherein the second direction is within plus or minus 45 degrees of being parallel to the first direction.

66. The system of Claim 37, further comprising a spring-loaded arm slidably coupled to the base such that removing the sensor system from the skin causes the sensor to automatically retract in response to the arm sliding relative to the base.

67. The system of Claim 66, wherein the base is configured to face towards the skin in a first direction, and the arm is configured to slide in a second direction that is within plus or minus 20 degrees of perpendicular to the first direction.

68. The system of Claim 67, wherein at least a portion of the sensor passes through a portion of the arm such that moving the arm in the second direction causes the portion of the arm to retract the sensor into an interior area of the sensor system.

69. The system of Claim 37, further comprising a spring and a release pin coupled to the base, wherein the spring is in at least one of a compressed state and an extended state such that removing the release pin causes the spring to move at least a first portion of the sensor into the base.

70. The system of Claim 69, further comprising an arm slidably coupled to the base, wherein the arm comprises a first channel aligned with a second hole of the base such that a second portion of the sensor passes through the first channel and the second hole, wherein the spring is at least one of compressed and extended between a first wall of the base and a second wall of the arm, wherein the release pin passes through a third hole of the base and interferes with a portion of the arm to prevent the spring from moving the arm to retract the sensor.

71. The system of Claim 70, wherein the release pin comprises a distal face having a second adhesive configured to be applied to the skin such that removing the base from the skin uncouples the first adhesive from the skin but does not uncouple the second adhesive from the skin, which causes the release pin to be removed from the third hole, which enables the spring to move the arm to retract the sensor.

72. The system of Claim 37, further comprising a spring-loaded arm slidably coupled to the base.

73. The system of Claim 72, wherein the spring-loaded arm is configured such that removing the sensor system from the skin causes the arm to contact a first portion of the sensor to bend the sensor such that a second portion of the sensor is located between the arm and the base.

74. The system of any of Claims 72 or 73, wherein the base is configured to face towards the skin in a first direction, the sensor system further comprising a spring oriented within plus or minus 20 degrees of perpendicular to the first direction, wherein the spring is located in an interior area of the sensor system and is configured to cause the arm to collide with the first portion of the sensor.

75. The system of any of Claims 72 or 73, wherein the base is configured to face towards the skin in a first direction, and

wherein the arm is configured to slide in a second direction that is within plus or minus 20 degrees of perpendicular to the first direction such that the second portion of the sensor is oriented within plus or minus 20 degrees of perpendicular to the first direction.

76. The system of any of Claims 70-73, wherein the sensor passes through a hole of the base, the first portion of the sensor is located distaliy relative to the hole of the base, the arm is spring-loaded towards the first portion of the sensor, and the arm comprises a protrusion that protrudes towards the first portion of the sensor such that sliding the arm causes the protrusion to collide with the first portion of the sensor and positions the protrusion directly distaliy relative to the hole of the base.

77. The system of Claim 76, wherein the protrusion of the arm comprises a second adhesive configured to couple the arm to the skin such that the second adhesive holds the arm in

a first position in winch the arm does not bend the sensor and such that uncoupling the second adhesive from the skin causes the arm to the bend the sensor such that the second portion of the sensor is located between the arm and the base.

78. The system of Claim 37, further comprising an arm rotatably coupled to the base such that the arm is configured to at least one of retract a distal portion of the sensor and cover the distal portion of the sensor.

79. The system of Claim 37, further comprising an arm rotatably coupled to the base by a hinge, wherein the hinge is configured such that uncoupling the base from the skin causes the hinge to rotate such that the arm bends at least a first portion of the sensor and covers at least a second portion of the sensor.

80. The system of Claim 79, further comprising a torsion spring coupled to the arm such that the torsion spring biases the arm in a rotational direction towards the second portion of the sensor.

81. The system of any of Claims 70 or 80, wherein the hinge is located in an interior area of the sensor system, and the arm comprises a portion configured to cover the second portion of the sensor, and

wherein the sensor system comprises a first state in which the portion of the arm is located in the interior area and a second state in which the portion of the arm is located distally relative to the base.

82. The system of Claim 37, wherein the sensor system further comprises a first portion and a second portion, wherein the second portion is coupled to the first portion by a hinge configured such that increasing a pivot angle between the first portion and the second portion retracts the sensor.

83. The system of Claim 82, further comprising a spring coupled to the base and configured to increase the pivot angle to retract the sensor.

84. The system of any of Claims 82 or 83, wherein the hinge comprises a pin rotatably coupled to a sleeve configured to retain the pin as the second portion rotates relative to the first portion.

85. The system of any of Claims 82, 83, or 84, wherein the base comprises the first portion and the second portion, and wherein the first portion couples the first adhesive to the second portion.

86. The system of any of Claims 82, 83, or 84, wherein the base comprises the first portion, and the second portion comprises the transmitter.

87. The system of any of Claims 82 to 86, wherein a distal portion of the sensor passes through a hole of the base, wherein a proximal portion of the sensor is coupled to the second portion such that increasing the pivot angle retracts the distal portion of the sensor through the hole of the base and into an area between the first and second portions of the sensor system.

88. The system of Claim 87, wherein the base comprises a left half and a right half, the left half comprises the hole of the base, and the right half comprises at least a portion of the hinge.

89. The system of any of Claims 82 to 88, wherein the second portion comprises a lift tab configured to enable a user to grip a distally facing surface to rotate the second portion relative to the first portion, wherein the lift tab comprises a protrusion that protrudes away from the hinge.

90. The system of Claim 37, wherein the base further comprises a first portion and a second portion, wherein the second portion of the base is coupled to the first portion of the base by a hinge configured such that decreasing a pivot angle between the first and second portions of the base places a portion of the sensor between the first and second portions of the base.

91. The system of Claim 90, wherein the hinge comprises a first pin rotatably coupled to a first channel configured to retain the first pin as the first portion of the base rotates relative to the second portion of the base.

92. The system of Claim 91, wherein the lunge comprises a second pin rotatably coupled to a second hole configured to retain the second pin as the first portion of the base rotates relative to the second portion of the base,

wherein the first pin protrudes in a first direction, the second pin protrudes in a second direction, and the first direction is opposite relative to the second direction.

93. The system of any of Claims 90-92, wherein the first adhesive comprises a first section and a second section, the first section is coupled to the first portion of the base such that the first section is configured to adhere the first portion of the base to the skin, and the second section is coupled to the second portion of the base such that the second section is configured to adhere the second portion of the base to the skin.

94. The system of Claim 93, wherein the hinge is configured to enable the first section of the first adhesive to face towards the second section of the first adhesive while the portion of the sensor is at least partially confined between the first and second portions of the base.

95. The system of any of Claims 90-94, wherein the system is configured to bend the portion of the sensor in response to rotating the hinge, wherein the portion of the sensor is bent between the first and second portions of the base to guard against a distal tip of the sensor penetrating tissue after the sensor system is removed from the skin.

96. The system of any of Claims 90-95, wherein the first portion of the base is rotationally spring-loaded relative to the second portion of the base such that the system is configured to decrease the pivot angle in response to a rotational spring bias.

97. The system of any of Claims 90-96, further comprising a torsion spring coupled to the hinge such that the torsion spring is configured to decrease the pivot angle to place the portion of the sensor between the first and second portions of the base.

98. The system of Claim 37, further an adhesive portion configured to bend at least a portion of the sensor towards the base, wherein a distal tip of the sensor is located between the base and the adhesive portion.

99. The system of Claim 37, further comprising an adhesive portion configured to collapse at least a portion of the sensor against the base.

100. The system of Claim 37, further comprising a sheet that covers a distal tip of the sensor and adheres to the first adhesive such that the sheet guards against the distal tip of the sensor penetrating tissue after the sensor system is removed from the skin.

101. The system of Claim 100, wherein the sheet is configured to be pliable.

102. The system of any of Claims 100-101 , wherein the first adhesive couples the sheet to the base.

103. The system of any of Claims 100-102, wherein the sheet comprises a first state in which the sheet is folded, is located proximally relative to the distal tip, does not cover the distal tip, and forms a tab configured to enable a user to unfold the sheet.

04. The sy stem of Claim 103, wherein the sheet comprises a second state in which the sheet is at least partially unfolded relative to the first state, is at least partially located distally relative to the distal tip, and the distal tip of the sensor is at least partially confined between the sheet and the first adhesive.

105. The system of Claim 100, wherein the sheet is a pliable sheet, the system further comprising a second sheet having a second puncture resistance that is greater than a first puncture resistance of the pliable sheet, wherein the second sheet is located between the distal tip and the pliable sheet to protect the pliable sheet from being punctured by the distal tip.

106. The system of Claim 105, wherein the first and second puncture resistances are measured using a distal tip of the sensor.

107. The system of any of Claims 105-106, wherein the second sheet is coupled to the pliable sheet such that the second sheet is configured to deform the distal tip as the pliable sheet is folded over the distal tip.

108. The system of Claim 37, wherein a distal tip of the sensor is at least partially confined between a pliable sheet and the base such that the pliable sheet holds at least a portion of the sensor in a bent position and the pliable sheet is adhered to the first adhesive.

109. The system of Claim 108, wherein the pliable sheet comprises a first state and a second state,

in the first state, the pliable sheet is located proximally relative to the first adhesive when the sensor system is coupled to the skin, and

in the second state, the pliable sheet is located distally relative to the first adhesive when the distal tip of the sensor is at least partially confined between the pliable sheet and the base.

110. The system of Claim 37, wherein the distal side of the base comprises a slot configured to receive a distal end of the sensor after the sensor is removed from the host.

111. The system of Claim 110, wherein a first portion of the sensor is bent such that the distal end of the sensor is located in the slot, and the distal end of the sensor is located proximally relative to the first adhesive.

1 12. The system of Claim 111, wherein the base comprises a hole, a second portion of the sensor passes through the hole, the slot is directly coupled to the hole, and the slot is oriented within plus or minus 20 degrees of perpendicular to the hole.

113. The system of Claim 37, wherein the sensor system further comprises a first portion and a second portion, the first portion couples the first adhesive to the second portion, and the second portion is rotatablv coupled to the first portion, wherein the sensor system is

configured to retract the sensor in response to rotating the second portion relative to the first portion.

1 14. The system of Claim 113, wherein the second portion is rotatably coupled to the first portion about an axis of rotation that is within plus or minus 20 degrees of being parallel to a proximal direction.

115. The system of any of Claims 113-114, wherein the base comprises the first portion, and the second portion comprises the transmitter.

116. The system of any of Claims 113-115, further comprising an interior area between the first portion and the second portion, wherein the interior area is configured such that spinning the second portion relative to the first portion retracts at least a portion of the sensor through a hole in the base and into the interior area.

117. The system of Claim 116, wherein the interior area is configured such that spinning the second portion relative to the first portion moves the interior area relative to at least one of the first portion and the second portion.

118. The system of any of Claims 113-1 17, wherein the base comprises a distal ly facing hole, and wherein the sensor comprises a proximal portion coupled to the second portion and a distal portion that passes through the hole in the base.

19. The system of any of Claims 1 13-1 18, further comprising a proximally facing indentation configured to provide traction for a user to rotate the second portion relative to the first portion.

120. The system of any of Claims 113-118, further comprising a proximally facing protrusion configured to provide traction for a user to rotate the second portion relative to the first portion.

121. The system of Claim 37, further comprising a cover coupled to the base such that a distal tip of the sensor is located in an interior area of the cover.

122. The system of Claim 37, further comprising an extendable cover having a first state configured to enable a distal end of the sensor to enter the host and having a second state configured to cover the distal end of the sensor after the sensor is removed from the host.

123. The system of Claim 122, wherein the first state is a contracted state, and the second state is an extended state.

124. The system of any of Claims 122-123, wherein the cover is a sheath having a channel in which a portion of the sensor is located.

125. The system of Claim 124, wherein the sheath is a pliable sheath.

26. The system of any of Claims 124-125, wherein the cover is rolled up along the channel.

127. The system of any of Claims 122-126, wherein the second state is a relaxed state such that the cover is configured to unroll from the first state in response to the sensor system being removed from the host.

128. The system of Claim 127, wherein the first state has higher stored mechanical energy than the second state such that the cover is configured to unroll from the first state in response to the sensor system being removed from the host.

129. The system of Claim 122, wherein the cover comprises an expandable portion configured to at least partially unfold to enable the cover to move from the first state to the second state.

130. The system of Claim 129, wherein the expandable portion comprises a pleated collapsible portion.

131. The system of any of Claims 129-130, wherein the expandable portion comprises a channel in which a first portion of the sensor is located.

132. The system of any of Claims 129-131 , wherein the cover comprises a distal hole in which a second portion of the sensor is located in the first state.

133. The system of any of Claims 129-132, wherein the first state has higher stored mechanical energy than the second state such that the expandable portion is configured to expand from the first state in response to the sensor system being removed from the host.

134. The system of Claim 37, further comprising a cap that covers a distal end of the sensor such that the cap is configured to prevent the distal end from penetrating a person after the sensor system is removed from the host.

135. The sy stem of Claim 134, wherein the cap is coupled to the distal side of the base.

136. The system of any of Claims 134-135, wherein the cap comprises a channel having a first central axis, the base comprises a hole having a second central axis, and a portion of the sensor passes through the hole and into the channel.

137. The system of Claim 136, wherein the first central axis is within 20 degrees of parallel to the second central axis.

138. The system of any of Claims 136-137, wherem the first central axis of the channel passes through the hole of the base.

139. The system of Claim 37, further comprising a cap coupled to the base, wherem the cap covers at least a majority of the first adhesive, and the cap covers a distal end of the sensor such that the cap is configured to prevent the distal end from penetrating a person after the sensor system is removed from the host and the cap is coupled to the base.

140. The system of Claim 139, wherem the cap comprises sidewalk that protrude proximally past at least a portion of an outer perimeter of the sensor system.

141. The system of Claim 37, further comprising a sensor cover configured to enable uncoupling the transmitter from the base in response to coupling the base to the sensor cover.

142. The system of Claim 37, further comprising a sensor cover configured to unlock the transmitter from the base in response to coupling the base to the sensor cover.

143. The system of Claim 142, wherein the transmitter is configured to be uncoupled from the base once the transmitter is unlocked from the base.

144. The system of Claim 37, further comprising a sensor cover having an interior area and a protrusion, wherein at least a portion of the base is located in the interior area of the sensor cover such that a distal end of the sensor is located between the base and the sensor cover.

145. The system of Claim 144, wherein the protrusion is located in a hole of the base such that the protrusion unlatches the transmitter from the base.

146. The system of Claim 144, further comprising a first flex arm and a wall, wherein the first flex arm comprises a first state in which the first flex arm interferes with the wall to lock the transmitter to the base.

147. The system of Claim 146, wherein the sensor cover comprises a protrusion configured such that coupling the base to the sensor cover causes the protrusion to move the first flex arm to a second state in which the first flex arm does not interfere with the wall such that the first flex arm does not lock the transmitter to the base.

148. The system of Claim 147, wherein the base comprises a hole through which at least a portion of the protrusion enters to deflect the first flex arm to the second state.

149. The system of any of Claims 147-148, wherein the sensor cover composes a housing and a second flex arm, the housing comprises an interior area, at least a portion of the base is located inside the interior area of the housing, the second flex arm couples the protrusion to the housing such that the second flex arm is configured to bend to move the protrusion to facilitate inserting the portion of the base into the interior area of the housing.

150. The system of Claim 149, wherein the second flex arm is configured to move in a distal direction in response to coupling the base to the sensor cover, the first flex arm is configured to move in a proximal direction in response to coupling the base to the sensor cover, and a portion of the sensor is bent in response to coupling the base to the sensor cover such that a distal end of the sensor is located between the base and the sensor cover.

151. The system of Claim 149, wherein the sensor cover comprises a first side and a second side, the first side is oriented within plus or minus 30 degrees of perpendicular to the second side, the first side comprises a first hole through which the portion of the base is inserted, and the second side comprises a second hole configured to provide access to a proximal surface of the transmitter to facilitate removing the transmitter from the base.

52. The system of any of Claims 144-151, further comprising a rail, wherein the rail slidably couples the base to the transmitter.

53. The system of Claim 37, further comprising a sensor cover configured to unlatch the transmitter from the base in response to coupling the base to the sensor cover, and a first flex arm configured to latch the base to the transmitter,

wherein the sensor cover comprises a second flex arm configured to deflect the first flex arm to unlatch the transmitter from the base.

154. The system of Claim 153, wherein the sensor cover comprises a distally facing wall, at least a portion coupled to the base is pressed against the distally facing wall such that a protrusion of the second flex arm is pressed into a hole of the base to deflect the first flex arm.

155. The system of Claim 37, further comprising a telescoping assembly coupled to the base, wherein at least a first portion of the sensor is located between a portion of the telescoping assembly and a distal side of the base such that the telescoping assembly is configured to move from a distal position to a proximal position to retract a second portion of the sensor.

156. The system of Claim 155, wherein the base composes an interior channel having a proximally facing opening, the telescoping assembly is located at least partially in the interior channel such that the telescoping assembly is configured to move proximally at least partially in the interior channel from the distal position to the proximal position.

157. The system of Claim 156, wherein, when the telescoping assembly is in the distal position, the first portion of the sensor is located in the interior channel of the base, and the second portion of the sensor is located distal ly relati ve to the base, and

wherein, when the telescoping assembly is in the proximal position, the first and second portions of the sensor are located in the interior channel of the base.

158. The system of Claim 155, wherein the telescoping assembly comprises a first section and a second section, wherein the first section is slidably coupled to the second section, and the second section is slidably coupled to an interior channel of the base such that the telescoping assembly is configured to telescope relative to the base to retract the sensor.

159. The system of Claim 158, wherein the interior channel comprises a first overhang configured to interfere with a second overhang of the second section to retain at least a portion of the second section within the interior channel.

160. The system of Claim 59, wherein the second section comprises a third overhang configured to interfere with a fourth overhang of the first section to limit a distance the first section can move proximally relative to the second section.

161. The system of Claim 158, further comprising a spring and a locking mechanism, wherein the locking mechanism is configured to lock the telescoping assembly in the distal position, wherein the locking mechanism comprises a first overhang of the base and a second overhang of the first section,

wherein the first and second overhangs are configured such that in a first angular position of the first section relative to the base, the first overhang interferes with the second overhang to limit proximal travel of the first section relative to the base, and

in a second angular position of the first section relative to the base, the first overhang does not limit the proximal travel of the first section relative to the base such that the spring pushes the telescoping assembly to the proximal position.

162. The system of Claim 158, wherein the base comprises a first overhang configured to limit a first proximal travel of the second section relative to the base, and the base comprises a second overhang configured to impede proximal movement of the first section such that the telescoping assembly is held in the distal position.

163. The system of Claim 158, wherem the base comprises a first channel, and the second section comprises a radially outward protrusion located in the first channel such that the first channel limits a first angular movement of the second section relative to the base while the second section permits a second angular movement of the first section relative to the second section and relative to the base.

164. The system of Claim 155, wherein the sensor comprises a coil that conductively couples a subcutaneous portion of the sensor to a connection portion of the sensor, wherein the connection portion of the sensor is located inside the base and communicatively couples the subcutaneous portion of the sensor to a communication module of the sensor system.

165. The system of Claim 164, wherein in the proximal position, the subcutaneous portion of the sensor is located within a center region of the coil of the sensor.

166. The system of Claim 164, wherein the coil of the sensor applies a biasing force to push the telescoping assembly to the proximal position.

67. The system of Claim 37, further comprising a housing slidably coupled to the base, wherein at least a first portion of the sensor is located between a portion of the housing and a distal side of the base such that the housing is configured to move from a distal position to a proximal position to retract a second portion of the sensor.

168. The system of Claim 167, wherein the base comprises an interior channel having a proximally facing opening, the housing is located at least partially in the interior channel such that the housing is configured to move proximally at least partially in the interior channel from the distal position to the proximal position to retract the second portion of the sensor into the interior channel.

169. The system of any of Claims 37, 167, or 168, further comprising a spring configured to retract a distal end of the sensor into the base after the sensor has been deployed.

170. The system of Claim 37, further comprising a cap coupled to the base and located proximally relative to the base, wherein a first portion of the sensor is coupled to the cap such that moving the cap proximally relative to the base retracts the sensor.

171. The system of Claim 170, wherein the cap is movable between a distal position and a proximal position, in the distal position a second portion of the sensor is located distally relative to the base, in the proximal position the second portion of the sensor is located proximally relative to the base, and an interlock removably secures the cap in the distal position.

172. The system of Claim 171, wherein at least a portion of an outer perimeter of the cap protrudes farther radially outward relative to a central axis of the second portion than the base such that the outer portion of the outer perimeter provides a distally facing wall to enable a user to grip the cap as the user moves the cap from the distal position to the proximal position.

173. The system of any of Claims 171-172, further comprising a linkage between the cap and the base, wherein the linkage limits a distance that the cap can move proximaliy relative to the base.

174. The system of Claim 173, wherein the linkage comprises an expandable portion configured to at least partially unfold to enable the cap to move from the distal position to the proximal position to retract the second portion of the sensor into the pleated expandable portion.

175. The system of Claim 173, wherein the expandable portion comprises bellows.

176. The system of any of Claims 168-165, wherein the cap is coupled to the transmitter such that moving the transmitter proximaliy retracts the sensor.

177. The system of Claim 37, wherein the system comprises a central axis oriented from a proximal end of the system to the distal side of the base, and wherein a distal portion of the sensor comprises a relaxed state in which the distal portion is oriented within plus or minus 45 degrees of perpendicular to the central axis of the system such that the relaxed state is configured to reduce a likelihood of the distal portion penetrating a person.

178. The system of Claim 177, wherein the distal portion of the sensor comprises a constrained state oriented within plus or minus 20 degrees of parallel to the central axis such that the distal portion is oriented distally, wherein the constrained state has higher stored mechanical energy than the relaxed state.

179. The system of Claim 178, further comprising a channel oriented within plus or minus 20 degrees of parallel to the central axis, wherein a section of the sensor is located in the channel such that the channel orients the distal portion of the sensor in the constrained state.

180. The system of Claim 179, wherein the channel comprises a slot, and the distal portion of the sensor is biased away from the slot such that a bias of the distal portion of the sensor is configured to facilitate maintaining the distal portion of the sensor in the channel.

181. The system of Claim 179, further comprising a telescoping applicator having the channel, wherein the applicator is removably coupled to the base such that the applicator is configured to orient the distal portion of the sensor in the constrained state and then is configured to be uncoupled from the base such that the distal portion of the sensor is capable of entering the relaxed state.

182. The system of Claim 178, further composing a telescoping applicator having a distal portion and a proximal portion, wherein the proximal portion of the applicator is configured to move distally relative to the distal portion of the applicator to insert the distal portion of the sensor into the skin,

wherein the distal portion of the applicator comprises a C-shaped channel, wherein a section of the sensor is located in the C-shaped channel such that the C-shaped channel orients the distal portion of the sensor in the constrained state, and wherein the applicator is configured such that the proximal portion of the applicator moves distally relative to the C-shaped channel to insert the d istal portion of the sensor into the skin.

183. The system of Claim 182, wherein the base is coupled to the proximal portion of the applicator such that the base is configured to move distally relative to the C-shaped channel and relative to the distal portion of the applicator as the sensor is inserted into the skin.

184. The system of Claim 37, further comprising a collapsible support member configured to resist non-axial forces of the sensor.

185. The system of Claim 84, wherein the collapsible support member comprises a proximal end, a distal end, and a length measured from the proximal end to the distal end, wherein the system is configured to reduce the length in response to moving the sensor from a proximal position to a distal position.

186. The system of Claim 185, wherein the collapsible support member comprises a channel, and a portion of the sensor passes through the channel, wherein the channel is configured to resist a buckling force of the sensor as the sensor moves from the proximal position to the distal position.

87. The system of Claim 185, wherein the collapsible support member comprises a foam block having a channel, wherein a portion of the sensor passes through the channel.

188. The system of Claim 185, wherein the collapsible support member comprises bellows having a channel, wherein a portion of the sensor passes through the channel.

89. The system of any of Claims 185-188, further comprising a tab coupled to the collapsible support member, wherein the system is configured such that actuating the tab causes the collapsible support member to collapse and causes at least a portion of the sensor to move distally relative to the base.

190. The system of Claim 37, further comprising a foam coupled to the base and a channel supported by the foam, wherein at least a portion of the sensor is located in the channel.

191. The system of Claim 190, wherein the portion of the sensor composes a central axis, the channel is configured to resist lateral displacement of the portion of the sensor relative to the central axis, and the foam is configured to compress in response to the system moving the sensor from a proximal position to a distal position.

192. The system of Claim 37, wherein the base comprises a distal portion and a proximal portion, the system comprises a channel having walls configured to compress in response to the system moving the sensor from a proximal position to a distal position, the channel is located at least partially between the distal portion and the proximal portion of the base such that a portion of the sensor is located in the channel, and the walls of the channel are configured to resist lateral displacement of the portion of the sensor.

193. The system of Claim 192, wherein the walls comprise foam configured to compress in response to moving the proximal portion distally towards the distal portion of the base.

194. The system of any of Claims 192-193, wherein the walls comprise a proximal section having a first material, an intermediate section having a second material, and a distal section having a third material.

195. The system of Claim 194, wherein the second material is more rigid than the first and third materials such that the intermediate section is configured to resist the lateral displacement.

196. The system of any of Claims 194-195, wherein the second material is stiffer than the first and third materials such that the intermediate section is configured to resist the lateral displacement.

197. The system of any of Claims 195-196, wherein the second material is less compressible than the first and third materials.

98. The system of any of Claims 92-197, further comprising an interlock configured to secure the proximal portion of the base to the distal portion of the base in response to the system moving the sensor from the proximal position to the distal position.

199. The system of Claim 37, further comprising bellows coupled to the base, wherein at least a portion of the sensor is located in an interior area of the bellows.

200. The system of Claim 199, wherein the portion of the sensor comprises a central axis, the bellows are configured to resist lateral displacement of the portion relative to the central axis, and the bellows are configured to compress in response to the system moving the sensor from a proximal position to a distal position.

201. The system of any of Claims 199-200, further comprising an interlock coupled to the base and configured to secure the bellows in a compressed state.

202. The system of any of Claims 199-201, further comprising a distal portion of the base and a proximal portion, wherein the bellows couple the distal portion to the proximal portion, the system further comprising a removable interference member located between the distal portion and the proximal portion such that the removable interference member is configured to block the system from moving the sensor from the proximal position to the distal position.

203. The system of Claim 37, further comprising a pull tab and a slot configured such that at least a portion of the sensor is located in the slot, wherein the system is configured such that pulling the pull tab causes the system to move the sensor from a proximal position to a distal position.

204. The system of Claim 203, further comprising a compliant sheet located in the slot and coupled to the pull tab such that the compliant sheet is configured to push the portion of the sensor distally in response to pullmg the pull tab.

205. The system of Claim 204, further comprising a housing coupled to the base, wherein the housing comprises the slot and is configured to cause the compliant sheet to push the portion of the sensor distally in response to pulling the pull tab.

206. The sy stem of any of Claims 203-205, wherein the slot comprises a distally facing opening configured to allow the portion of the sensor to exit the slot distally and enter subcutaneous tissue of the host.

207. The system of Claim 37 further comprising a guide member configured to resist non-axial forces of the sensor.

208. The system of Claim 207, wherein the guide member comprises an engagement feature releasably coupled to the sensor, wherein the engagement feature is configured to

uncouple from the sensor in response to moving the sensor from a proximal position to a distal position.

209. The system of Claim 207, wherein the guide member comprises a first portion and a second portion, and wherein at least a portion of the sensor is located between the first and second portions of the guide member such that the first and second portions of the guide member are configured to resist a buckling force of the sensor.

210. The system of Claim 209, wherein the first portion is configured to move relative to the second portion of the guide member in response to the system moving the sensor from a proximal position to a distal position.

211. The system of Claim 210, wherein the guide member is configured such that displacement of the first portion relative to the second portion permits moving the sensor from the proximal position to the distal position.

212. The system of Claim 209, wherein the portion of the sensor comprises a central axis, the first and second portions form a channel, the portion of the sensor is located in the channel, and the channel is configured to resist displacement of the portion of the sensor in a direction perpendicular to the central axis.

213. The system of Claim 37, further comprising a channel having a first side and a second side configured to at least partially separate in response to the system moving the sensor from a proximal position to a distal position.

214. The system of Claim 213, wherein a portion of the sensor is located in the channel such that the channel is configured to at least partially separate to permit the sensor to move from the proximal position to the distal position.

215. The system of Claim 214, wherein the portion of the sensor comprises a central axis, and the channel is configured to resist displacement of the portion of the sensor in a direction perpendicular to the central axis.

216. The system of Claim 37, wherein the sensor is coupled to a housing that is slidably coupled to the base, wherein the system is configured to move a portion of the sensor away from the distal side of the base in response to moving the housing in a first direction withm plus or minus 20 degrees of perpendicular to a distal direction.

217. The system of Claim 37, further comprising a housing slidably coupled to the base, wherein the base comprises a channel that is at least one of curved and angled, a portion of the sensor is located in the channel, and the channel is configured to deflect the portion of the sensor to redirect the portion distally in response to moving the housing relative to the base.

218. The system of Claim 217, further comprising a sensor path having a first section and a second section, wherein the first section is oriented within plus or minus 20 degrees of perpendicular to a distal direction, and the second section is oriented within plus or minus 45 degrees of parallel to the distal direction, wherein the system is configured to deflect the sensor to cause the sensor to follow the sensor path.

219. The system of Claim 37, wherein the base comprises a first portion and a second portion, the first portion is configured to couple the second portion to the skin, the second portion is slidably coupled to the first portion, and the base is configured such that moving the second portion in a first direction within plus or minus 20 degrees of perpendicular to a distal direction causes a distal tip of the sensor to move in a second direction within plus or minus 45 degrees of parallel to the distal direction.

220. The system of Claim 219, wherein the sensor comprises a distal section and a proximal section, the proximal section is rigidly coupled to the second portion of the base, and the distal section passes through a channel of the first portion of the base.

221. The system of Claim 220, wherein the channel comprises a radius configured to deflect at least a portion of the sensor such that the portion of the sensor is redirected distally.

222. The system of Claim 221 , wherein the sensor is a glucose sensor, and the transmitter is coupled to the second portion of the base such that the second portion slidably couples the transmitter to the first portion of the base.

223. The system of any of Claims 220-222, further comprising at least one rail that slidably couples the second portion to the first portion of the base.

224. The system of Claim 37, further comprising a removable applicator coupled to the base, wherein the applicator comprises a curved channel configured to guide a portion of the sensor along a curved path as the portion of the sensor moves from a proximal position to a distal position.

225. The system of Claim 224, wherein the applicator comprises a leaf spring configured to move the portion of the sensor along the curved path through the curved channel.

226. The system of Claim 37, further comprising a curved channel coupled to the base, wherein a curved portion of the sensor is located in the curved channel, and the curved channel is configured to resist buckling forces of the curved portion as the system moves the curved portion from a proximal position to a distal position.

227. The system of Claim 226, further a spring configured to move the curved portion from the proximal position to the distal position.

228. The system of Claim 227, wherein the spring is a leaf spring in a flexed state.

229. The system of Claim 228, further comprising an interlock configured to releasably hold the leaf spring in the flexed state, wherein the system is configured to move the curved portion from the proximal position to the distal position in response to releasing the interlock.

230. The system of Claim 229, further comprising a pull tab coupled to the interlock such the system is configured to disengage the interlock to enabie the spring to move the curved portion from the proximal position to the distal position in response to pulling the pull tab.

231. The system of any of Claims 226-230, further comprising a removable applicator having the curved channel, wherein the applicator is configured to facilitate moving the curved portion from the proximal position to the distal position.

232. The system of Claim 37, further comprising a first arm and a wall coupled to the base, wherein a portion of the sensor is secured between the first arm and the wall such that the first arm is configured to resist buckling forces of the sensor as the system moves the portion from a proximal position to a distal position.

233. The system of Claim 232, wherein the first arm is movably coupled to the base such that at least a portion of the first arm is configured to move to enable the system to move the portion of the sensor from the proximal position to the distal position.

234. The system of any of Claims 232-233, wherein at least one of the first arm and the wall form a channel, and the portion of the sensor is at least partially located in the channel such that the channel is configured to resist the buckling forces.

235. The system of any of Claims 232-234, further comprising a distal protrusion configured to move the first arm away from the wail to enable the system to move the portion of the sensor from the proximal position to the distal position.

236. The system of any of Claims 232-235, wherein the portion of the sensor comprises a central axis, and the first arm protrudes in a direction within plus or minus 45 degrees of perpendicular to the central axis.

237. The system of Claim 37, further comprising a removable applicator having a telescoping assembly coupled to the base, wherein the telescoping assembly comprises a first set of tongs configured to resist a first buckling force of a first section of the sensor.

238. The system of Claim 237, wherein the telescoping assembly comprises a second set of tongs configured to resist a second buckling force of a second section of the sensor, and wherein the telescoping assembly comprises a distal protrusion configured to move distally into a first area between the first set of tongs and into a second area between the second set of tongs to expand the first and second sets of tongs.

239. The system of Claim 37, further comprising a removable applicator coupled to the base and having a pair of biasing members, wherein a portion of the sensor is located in an area between the pair of biasing members such that the pair of biasing members is configured to resist buckling forces of the sensor.

240. The system of Claim 239, wherein the pair of biasing members is held in a compressed state by a channel configured to enable the pair of biasing members to expand in response to moving the pair of biasing members far enough distally that a distal end of the sensor is located distally relative to a distal end of the applicator.

241. The system of any of Claims 239-240, wherein the pair of biasing members comprises a set of tongs.

242. The system of Claim 37, further comprising a first arm and a second arm that extend distally, wherein a portion of the sensor is located between the first and second arms such that the first and second arms are configured to resist buckling forces of the sensor.

243. The system of Claim 242, wherein the first and second arms are located in a channel of the system, and the channel holds the first and second arms in a compressed state.

244. The system of Claim 243, wherein the channel is configured such that moving the first and second arms distally causes the first and second arms to spread apart from each other to facilitate the system moving the portion of the sensor from a proximal position to a distal position.

245. The system of Claim 37, further comprising a first arm and a second arm that extend distally and are configured to have a closed state in which the first and second arms resist buckling forces of a portion of the sensor located between the first and second arms, and

the first and second arms are configured to have an open state to enable the system to move the portion of the sensor from a proximal position to a distal position.

246. The system of Claim 37, further comprising a tube coupled to the base and having a slot from a proximal portion of the tube to a distal portion of the tube, wherein the tube is configured to resist buckling forces of the sensor, and the slot is configured to enable moving a first portion of the sensor distally outside of the tube while moving a second portion of the sensor distally inside the tube.

247. The system of Claim 246, further comprising a removable applicator coupled to the base, wherein the applicator couples the tube to the base such that the system is configured to move the base distally relative to the tube to pierce the skin with a distal end of the sensor.

248. The system of any of Claims 246-247, wherein the tube comprise a first side of the slot and a second side of the slot, wherein the first and second sides of the slot are coupled together by a linkage configured to break open in response to moving the first portion of the sensor distally.

249. The system of any of Claims 246-248, wherein the tube is at least 4 millimeters long as measured along a central axis of the tube.

250. The system of Claim 37, further comprising an applicator having a channel configured to resist buckling forces of the sensor, wherein a distal portion of the sensor is located inside the channel, a proximal portion of the sensor is located outside the channel, an intermediate portion of the sensor couples the distal and proximal portions of the sensor, and the intermediate portion of the sensor is located in a slot of the channel.

251. The system of Claim 250, wherein the slot is configured to enable the intermediate portion of the sensor to move distally through the slot as the sensor moves from a proximal position to a distal position.

252. The system of Claim 251 , wherein the channel comprises a central axis oriented distally such that the channel is configured to guide the distal portion of the sensor towards the skin.

253. The system of any of Claims 250-252, wherein the slot is oriented radially outward from the central axis.

254. The system of any of Claims 250-253, wherein the slot comprises at least one linkage that couples a first side of the slot to a second side of the slot, wherein the at least one linkage is configured to break in response to moving the intermediate portion of the sensor distally through the slot.

255. The system of any of Claims 250-254, wherein the slot is configured to expand in response to moving the intermediate portion of the sensor distally through the slot.

256. The system of Claim 37, further comprising a telescoping assembly coupled to the base, wherein the telescoping assembly comprises a distal portion, a proximal portion slidably coupled to the distal portion, and a spring compressed between the proximal portion and the base, wherein the proximal portion releasably secures the sensor in a first proximal starting position such that the spring is configured to push the base and the sensor distally in response to the system unlatching the base from the proximal portion.

257. The system of Claim 256, wherein the proximal portion comprises a latch configured to releasably secure the base in a second proximal starting position.

258. The system of Claim 257, wherein the latch is configured to release the base in response to moving the proximal portion distally relative to the distal portion to enable the spring to push the base and the sensor distally.

259. The system of Claim 257, wherein the sensor is configured to move along a first path from the first proximal starting position to a first distal ending position, the proximal portion is configured to move along a second path from a third proximal starting position to a third distal ending position, and the first path of the sensor is at least 40 percent longer than the second path of the proximal portion.

260. The system of Claim 259, wherein the system is configured to cause the sensor to move a first distance in response to the proximal portion moving a second distance that is at least 50 percent shorter than the first distance.

261. The system of Claim 259, wherein the proximal portion comprises a distally protruding arm having an inward protrusion that passes through a hole of the distal portion and is coupled to the base to secure the sensor in the first proximal starting position.

262. The system of Claim 261, wherein the system is configured such that moving the proximal portion distally relative to the distal portion causes the distally protruding arm to flex outward to release the inward protrusion from the base to enable the spring to push at least a portion of the sensor into the skin.

263. The system of Claim 261, wherein the system is configured to move the sensor a first distance in response to moving the proximal portion a second distance to unlatch the base, wherein the first distance is at least twice as long as the second distance such that the system is configured to magnify a first movement of the proximal portion into a larger second movement of the sensor.

264. The system of Claim 261, wherein the distal portion comprises a channel configured to orient the base as the spring pushes the base distally.

265. The system of Claim 37, further comprising a first housing rotatably coupled to the base, and a sprmg compressed between a portion of the first housing and the sensor, wherein the system is configured to unlatch the sensor from the first housing to enable the spring to move the sensor distally in response to rotating the first housing relative to the base.

266. The system of Claim 265, wherein the first housing comprises a first central axis, the sensor comprises a portion configured to pierce the skin, the portion comprises a second central axis, and the first central axis is oriented within plus or minus 20 degrees of parallel to the second central axis.

267. The system of any of Claims 265-266, wherein the spring comprises at least one of a helical spring and a conical spring configured to expand distally to move the sensor distally.

268. The system of Claim 37, further comprising a first housing rotatably coupled to the base, a second housing coupled to the sensor, and a spring compressed between a proximal end of the first housing and the sensor such that the spring is configured to push the second housing and the sensor distally relative to the base and the first housing in response to rotating the first housing relative to the base.

269. The system of Claim 268, wherein the second housing is located in an interior area of the first housing, and the first adhesive is configured to secure the base to the skin to enable the first housing to rotate relative to the base and relative to the second housing.

270. The system of Claim 269, wherein the first housing comprises a first central axis, the sensor comprises a portion configured to pierce the skin, the portion comprises a second central axis, and the first central axis is oriented within plus or minus 10 degrees of parallel to the second central axis.

271. The system of Claim 268, wherein the spring comprises a conical spring configured to expand in response to rotating the first housing relative to the base.

272. The system of Claim 268, further comprising a mechamcal interlock between the first housing and the second housing, wherein the mechanical interlock is configured to releasabiy hold the spring in a compressed state such that the sensor is in a proximal starting position.

273. The system of Claim 272, wherein the mechanical interlock comprises a first protrusion of the first housing that interferes with distal movement of a second protrusion of the second housing.

274. The system of Claim 273, wherein the mechanical interlock is configured such that rotating the first protrusion relative to the second protrusion causes the second protrusion to fall distaliy off the first protrusion and thereby enables the second housing to move distally relative to the first housing.

275. The system of Claim 273, wherein the first protrusion is oriented radially outward, and the second protrusion is oriented radially inward.

276. The system of Claim 272, wherein the mechanical interlock comprises a ridge and a groove configured such that rotating the first housing relative to the base requires overcoming a torque threshold to move the ridge out of the groove.

277. The system of Claim 268, wherein an interface between the second housing and the base comprises a ridge located in a groove configured to limit rotation of the second housing relative to the base during rotation of the first housing relative to the base.

278. The system of Claim 277, wherein the interface is oriented from a proximal portion of the second housing to a distal portion of the second housing.

279. The system of Claim 37, further comprising a removable applicator coupled to the base, wherein the applicator comprises a rotating housing configured to push first and second bodies distally, wherein a second adhesive couples the base to the first body, and the second body is configured to hold the base in a distal position while the first body moves proximally to uncouple the first body from the base.

280. The system of Claim 279, further comprising a locking mechanism configured to block rotational movement of the rotating housing, wherein the system is configured to disengage the locking mechanism in response to linear movement of the rotational housing.

281. The system of Claim 37, further comprising a removable applicator coupled to the base, wherein the applicator comprises:

a first housing;

a second housing rotatably coupled to the first housing;

a torsion spring having a first portion coupled to the first housing and a second portion coupled to the second housing such that the torsion spring is configured to rotate the second housing relative to the first housing;

a first body slidably coupled to the first housing and coupled to the second housing such that the first body is configured to linearly push the sensor from a proximal starting position to a distal ending position in response to the second housing rotating relative to the first housing; and a second body slidably coupled to the first housing and coupled to the second housing such that the second body is configured to block proximal movement of the sensor after the sensor has reached the distal ending position as the system uncouples the first body from the base.

282. The system of Claim 281, wherein a second adhesive couples the first body to the base, and wherein the first and second bodies are configured to move linearly and distally in response to rotating the second housing relative to the first housing.

283. The system of Claim 282, wherein the second body is configured to block the proximal movement of the sensor as rotation of the second housing relative to the first housing uncouples the second adhesive from the base to enable the first body to move proximally relative to the base and relative to the second body.

284. The system of Claim 282, wherein the first body is coupled to a first linear channel, and a first protrusion couples the first linear channel to the second housing, wherein the first linear channel is configured such that a first rotational movement of the second housing relative to the first housing causes a first distal linear movement of the first body relative to the first housing.

285. The system of Claim 282, wherein the second body is coupled to a second channel having a curved portion, and the first protrusion couples the second channel to the second housing, wherein the second channel is configured such that the first rotational movement of the second housing relative to the first housing causes a second distal linear movement of the second body relative to the first housing.

286. The system of Claim 285, wherein the curved portion of the second channel is configured such that continued rotational movement of the second housing relative to the first

housing after the sensor has reached the distal ending position does not cause proximal movement of the second body as the continued rotational movement uncouples the second adhesive from the base by moving the first body proximal ly.

287. The system of Claim 281, wherein the second housing is coupled to the first housing by a second protrusion about which the second housing is configured to rotate relative to the first housing.

288. The system of Claim 287, wherein the second housing is slidabiy coupled to the second protrusion such that the second housing is configured to move from a first position to a second position along the second protrusion.

289. The system of Claim 288, wherein in the first position, a third protrusion blocks rotational movement of the second housing relative to the first housing to impede distal movement of the sensor.

290. The system of Claim 289, wherein the first housing comprises a button configured to move the second housing from the first position to the second position in which the second housing is configured to rotate relative to the first housing to move the sensor distally.

291. The system of Claim 37, wherein the base comprises a proximal portion coupled to a distal portion by flex arms.

292. The system of Claim 291, wherein the flex arm are configured to cause the proximal portion to rotate relative to the distal portion in response to moving the proximal portion distally relative to the distal portion to insert at least a portion of the sensor into the skin.

293. The system of any of Claims 291 -292, wherein the proximal portion couples the transmitter to the distal portion.

294. The system of any of Claims 291-293, wherein the flex arms comprise at least one living hinge.

295. The system of Claim 294, wherein the flex arms are configured to rotate the proximal portion relative to the distal portion in response to moving the sensor distally.

296. The system of any of Claims 291-295, wherein the flex arms are spaced around a distal end of the sensor.

297. The system of Claim 296, wherein the flex arms are configured to rotate the distal end as the distal end moves from a proximal starting position to a distal ending position.

298. The system of any of Claims 291-297, further comprising a removable interference member located between the distal portion and the proximal portion such that the removable interference member is configured to block the system from moving the sensor from a proximal starting position to a distal ending position.

299. The system of Claim 37, wherein the base comprises a proximal portion coupled to a distal portion by a first arm and a second arm, a distal end portion of the sensor comprises a central axis, the first arm is oriented at a first angle of plus or minus 45 degrees of perpendicular to the central axis, and the second arm is oriented at a second angle of plus or minus 45 degrees of perpendicular to the central axis.

300. The system of Claim 299, wherein the first and second arms are configured to cause the proximal portion to rotate relative to the distal portion in response to moving the distal end portion of the sensor from a proximal starting position to a distal ending position.

301. The system of any of Claims 299-300, wherein the second arm slants away from the first arm.

302. The system of Claim 37, wherein the base comprises a first portion and a second portion coupled by a hinge configured such that pivoting the second portion towards the first portion causes the sensor to move from a proximal starting position to a distal ending position.

303. The system of Claim 302, wherein the second portion couples the transmitter to the first portion, and the first portion couples the first adhesive to the second portion.

304. The system of any of Claims 302-303, wherein the base is configured such that decreasing a pivot angle between the first portion and the second portion moves a distal end of the sensor out of a hole of the distal side of the base to facilitate the distal end piercing the skin.

305. The system of Claim 304, wherein a proximal segment of the sensor is coupled to the second portion such that the system is configured to move a portion of the sensor out of an area between the first and second portions and distally through the hole of the base in response to decreasing the pivot angle.

306. The system of Claim 304, wherein the base comprises a left half and a right half, the left half comprises the hole of the base, and the right half comprises the hinge.

307. The system of any of Claims 302 or 304 wherein the hinge comprises a pin rotatabiy coupled to a sleeve configured to retain the pin as the second portion rotates relative to the first portion.

308. The system of Claim 302, further comprising a spring configured to facilitate pivoting the second portion relative to the first portion.

309. The system of Claim 308, wherein the spring is a torsional spring configured to apply a torque about the hinge.

310. The system of Claim 308, wherein the spring is a leaf spring configured to apply a torque about the hinge.

311. The system of Claim 37, further comprising a removable applicator coupled to the base, wherein the applicator comprises:

a housing;

a first body rotatably coupled to the housing by a hinge having a hinge axis;

a second body rotatably coupled to the housing about the hinge axis;

a first spring configured to rotate the first body in a first rotational direction to move the sensor from a proximal starting position to a distal ending position; and

a second spring configured to rotate the second body in a second rotational direction that is opposite to the first rotational direction.

312. The system of Claim 311, wherein the second body is configured to couple the base to the housing as the first body rotates in the first rotational direction.

313. The system of any of Claims 31 -3 2, wherein the first body is configured to hold the sensor in the distal ending position while the second body uncouples the base from the applicator by rotating in the second rotational direction.

314. The system of Claim 311, further comprising a first mechanical interlock that releasably couples the second body to the base such that the first body is configured to move the second body and the base in the first rotational direction.

315. The system of Claim 314, wherein the first body is located at least partially between the base and the second body, and the first mechanical interlock comprises a third flex arm that secures the first body at least partially between the base and the second body.

316. The system of any of Claims 314-315, wherein the first mechanical interlock is configured to uncouple from the base to enable the second body to rotate in the second rotational direction in response to the first body moving the second body in the first rotational direction.

317. The system of Claim 316, wherein the housing comprises a second mechanical interlock configured to hold the first body in a distal position while the second body rotates in the second rotational direction.

318. The system of Claim 3 7, wherein the second mechanical interlock comprises a fourth flex arm configured to couple to least a portion of the first body.

319. The system of Claim 314, further comprising a fifth flex arm that couples the first body to the housing such that the sensor is in the proximal starting position, wherein the fifth flex arm is configured to resist a rotational force of the first spring.

320. The system of Claim 319, wherein a portion of the fifth flex arm protrudes from an exterior of the housing such that the portion comprises an actuation tab, wherein the fifth flex arm is configured to uncouple from the housing to enable the first body to rotate in response to moving the actuation tab.

321. The system of Claim 37, wherein the sensor comprises a distal end portion having a central axis and a planar profile coincident with the central axis, wherein the planar profile of the distal end portion is parabolic.

322. The system of Claim 321, wherein the distal end portion of the sensor is coated with a membrane, and a distal tip of the sensor is configured to pierce the skin and is rounded to resist delamination of the membrane.

323. The system of Claim 321, wherein the distal end portion of the sensor is coated with a membrane, and the parabolic distal end portion is configured to provide a gradual diameter increase to reduce tissue trauma and to provide a curved distal tip to resist delamination of the membrane.

324. The system of any of Claims 321-323, wherein a slope of the parabolic distal end portion comprises a linear derivative.

325. The system of any of Claims 321-324, wherein a segment of the sensor is configured to be inserted into the skin and comprises a first maximum width, wherein the parabolic distal end portion comprises a second maximum width that is at least 50 percent of the first maximum width.

326. The system of any of Claims 324, 324, or 325, wherein the distal end portion is coated by a membrane configured to enable the sensor system to measure a glucose indication.

327. The system of Claim 326, wherein the membrane comprises a thickness that vanes by less than plus or minus 30 percent relative to an average thickness of the membrane.

328. The system of Claim 326, wherein the parabolic distal end portion comprises a distal section and a proximal section, the distal section comprises a first angle relative to the central axis, the proximal section comprises a second angle relative to the central axis, and the first angle is at least twice as large as the second angle such that the first angle is configured to resist delamination of the membrane and the second angle is configured to gradually increase a width of the profile.

329. The system of Claim 37, wherein the sensor comprises a distal end portion having a central axis and a planar profile coincident with the central axis, wherein a distal tip of the sensor is curved such that the planar profile comprises a curved distal end that couples a first curved side to a second curved side.

330. The system of Claim 329, wherein the distal end portion of the sensor is coated with a membrane, and the curved distal end is configured to resist delamination of the membrane.

331. The system of Claim 330, wherein the first and second curved sides are configured to provide a smooth transition from the distal tip to resist delamination and provide a gradual transition from a first diameter of the distal tip to a maximum diameter of the distal end portion.

332. The system of any of Claims 321, 329, 335, 337, 339, 345, 349, 360, 361, 362, 363, 365, 369, 371 , or 377, wherein the sensor is a glucose sensor having a conductive core and a conductive layer configured to enable the system to apply a voltage between the conductive core and the conductive layer to measure a glucose indication.

333. The system of Claim 332, wherein the sensor comprises a first electrical insulation layer located around a first section of the conductive core, and the sensor comprises a second electrical insulation layer located around a second section of the conductive core, and wherein the conductive layer is located radially outward from the first insulation layer, and the first insulation layer is spaced apart from the second insulation layer to form a gap configured to enable the system to apply the voltage between the conductive core and the conductive layer.

334. The system of Claim 333, wherein the sensor comprises an electrical insulation cap that covers a distal end of the conductive core.

335. The system of Claim 37, wherein the sensor comprises a distal end portion that is conical with a rounded distal tip.

336. The system of Claim 335, wherein the rounded distal tip is configured to resist delamination of a membrane that coats the distal end portion, and the distal end portion is conical to facilitate piercing the skin.

337. The system of Claim 37, wherein the sensor comprises a distal end portion that is conical with a blunted tip.

338. The system of Claim 337, wherein the blunted tip is configured to resist delamination of a membrane that coats the distal end portion, and the distal end portion is conical to facilitate piercing the skin.

339. The system of Claim 37, wherein the sensor comprises a distal end portion having a central axis and a planar profile coincident with the central axis, wherein a distal tip of the sensor is curved such that the planar profile comprises a curved distal end that couples a first straight side to a second straight side.

340. The system of Claim 339, wherein the distal end portion is coated by a membrane, and the distal tip is curved such that the distal tip is configured to resist delamination of the membrane.

341. The system of Claim 340, wherein the first and second sides are straight such that the first and second sides are configured to linearly increase a diameter of the distal end portion to reduce tissue trauma caused by inserting the distal end portion into the skin.

342. The system of Claim 339, wherein the curved distal end comprises a radius that is greater than 10 micrometers and less than 35 micrometers such that the curved distal end is configured to be large enough to resist delamination of a membrane that coats the curved distal end and small enough to reduce patient discomfort associated with piercing of the skin.

343. The system of Claim 339, wherein the curved distal end comprises a maximum width that is greater than 10 micrometers and less than 35 micrometers such that the curved distal end is configured to be large enough to resist delamination of a membrane that coats the curved distal end and small enough to reduce patient discomfort associated with piercing of the skin.

344. The system of Claim 339, wherein an angle between the first and second straight sides is greater than 15 degrees and less than 25 degrees such that the angle is configured to reduce patient discomfort associated with piercing of the skin.

345. The system of Claim 37, wherein the sensor comprises a distal end portion having a central axis and a planar profile coincident with the central axis,

wherein the planar profile comprises a left portion having a first side coupled to a second side, and the planar profile comprises a right portion having a third side coupled to a fourth side, and

wherein a first angle between the first side and the third side is smaller than a second angle between the second side and the fourth side such that a proximal section of the end portion provides a more gradual width increase than a distal section of the end portion.

346. The system of Claim 345, wherein the first, second, third, and fourth sides are straight.

347. The system of any of Claims 345-346, further comprising a curved distal end that couples the second side to the fourth side, wherein the curved distal end is configured to resist delamination of a membrane that coats the distal end portion of the sensor.

348. The system of any of Claims 345-347, wherein the sensor is a glucose sensor comprising a membrane that coats the distal end portion of the sensor, wherein the distal end portion is configured to resist delamination of the membrane, reduce tissue trauma, and reduce patient discomfort caused by piercing the skin.

349. The system of Claim 37, wherein the sensor comprises a distal end portion having a central axis and a first facet oriented at a first angle of less than 25 degrees relative to the central axis such that the first facet is configured to facilitate piercing the skin.

350. The system of Claim 349, wherein the distal end portion of the sensor comprises a second facet oriented at a second angle of less than 25 degrees relative to the central axis.

351. The system of Claim 350, wherein the first facet is oriented at a third angle relative to the second facet, and wherein the third angle is greater than 10 degrees and less than 25 degrees.

352. The system of Claim 351, wherein the first and second facets form a wedge configured to facilitate piercing the skin.

353. The system of Claim 351, wherein the distal end portion of the sensor is coated by a membrane, and a rounded ridge couples the first facet to the second facet such that the rounded ridge is configured to resist delamination of the membrane.

354. The system of Claim 350, wherein the distal end portion of the sensor comprises a third facet oriented at a fourth angle of less than 25 degrees relative to the central axis.

355. The system of Claim 354, wherein the first, second, and third facets form a triangular pyramid configured to facilitate piercing the skin.

356. The system of Claim 355, wherein the distal end portion of the sensor is coated by a membrane, and the triangular pyramid comprises a rounded distal tip configured to resist delamination of the membrane.

357. The system of Claim 354, wherein a first rounded ridge couples the first facet to the second facet, and a second rounded ridge couples the second facet to the third facet, wherein the first and second rounded ridges are configured to reduce tissue trauma caused by inserting the distal end portion of the sensor into the host,

358. The system of Claim 354, wherein the distal end portion of the sensor comprises a fourth facet oriented at a fifth angle of less than 25 degrees relative to the central axis.

359. The system of Claim 358, wherein the first, second, third, and fourth facets form a rectangular pyramid configured to facilitate piercing the skin.

360. The system of Claim 37, wherein the sensor comprises a conductive distal end portion coated by a membrane, and the conductive distal end portion comprises a first step configured to resist proximal movement of the membrane relative to the first step.

361. The system of Claim 37, wherein the sensor comprises a tapered end section coated by a membrane and having a distal tip, wherein the tapered end section comprises a first step configured to resist proximal movement of the membrane relative to the first step.

362. The system of Claim 37, wherein the sensor comprises a tapered end section coated by a membrane and having a distal tip, the sensor comprises a first step located within plus or minus 1 millimeter of the tapered end section, and the first step is configured to resist proximal movement of the membrane relative to the first step.

363. The system of Claim 37, wherein the sensor is coated by a membrane and comprises a first step, the sensor comprises a groove configured to be inserted into tissue of the host, the first step is located distally relative to the groove, and the first step is configured to resist proximal movement of the membrane relative to the first step.

364. The system of any of Claims 360-363, wherein the first step comprises a surface oriented within plus or minus 25 degrees of perpendicular to a central axis of the portion of the sensor.

365. The system of any of Claims 360-364, wherein the sensor comprises a first conductive layer electrically insulated from a second conductive layer by an insulation layer, wherein the first conductive layer is conductiveiy coupled to the conductive distal end portion such that the conductive distal end portion is configured to be conductiveiy coupled to the second conductive layer via tissue of the host.

366. The system of Claim 37, wherein the sensor comprises a portion coated by a membrane, the portion of the sensor comprises a first conductive layer electrically insulated from a second conductive layer by an insulation layer, the first conductive layer is configured to be electrically coupled to the second conductive layer via tissue of the host, the first conductive layer extends farther distally than the second conductive layer, the first conductive layer comprises a first step configured to resist proximal movement of the membrane relative to the first step, and the first step is located farther distally than the second conductive layer.

367. The system of Claim 37, wherein a distal portion of the sensor comprises a first step and a second step spaced proximal ly relative to the first step, the distal portion of the sensor is coated by a membrane, the first and second steps face distally, and the first step is configured to resist proximal movement of the membrane relative to the first step.

368. The system of any of Claims 366-367, wherein the first step comprises a surface oriented within plus or minus 25 degrees of perpendicular to a central axis of the portion of the sensor.

369. The system of any of Claims 366-367, wherein the first step comprises a surface oriented withm plus or minus 15 degrees of perpendicular to a central axis of the portion of the sensor.

370. The system of any of Claims 368-369, wherein the surface forms an interference feature configured to impede proximal movement of the membrane relative to the surface by causing a compressive force withm the membrane in response to the proximal movement of the membrane.

371. The system of Claim 37, wherein the sensor comprises a distal end portion coated by a membrane, the distal end portion comprises a gap between a conductive core and a conductive layer of the sensor, and the gap is configured to enable a subcutaneous current between the conductive core and the conductive layer, and

wherein the distal end portion comprises a step located distaliy relative to the gap and configured to resist proximal movement of the membrane relative to the step.

372. The system of Claim 371, wherein the step comprises a surface oriented within plus or minus 25 degrees of perpendicular to a central axis of the distal end portion.

373. The system of Claim 372, wherein the surface forms an interference feature configured to impede proximal movement of the membrane relative to the surface by causing a compressive force within the membrane in response to the proximal movement of the membrane.

374. The system of any of Claims 371-373, wherein the conductive core comprises the step.

375. The system of any of Claims 371-373, wherein an insulation layer located around the conductive core forms the step.

376. The system of any of Claims 371-375, wherein the distal end portion comprises at least one of a rounded distal tip, a parabolic shape, a conical shape, a wedge shape, a triangular pyramid shape, and a rectangular pyramid shape such that the distal end portion is configured to facilitate piercing the skin.

377. The system of Claim 37, wherein the sensor comprises a distal end portion coated by a membrane,

the distal end portion of the sensor comprises a central axis, a distal tip, and a distaliy facing surface spaced proximally apart from the distal tip, and

the distaliy facing surface forms a mechanical interlock with the membrane such that the mechanical interlock is configured to impede proximal movement of the membrane relative to the distaliy facing surface.

378. The system of Claim 377, wherein the sensor comprises a conductive core, a conductive layer, and an insulation layer configured to electrically insulate the conductive core from the conductive layer, wherein the conductive core extends farther distaliy than the insulation layer to form a shortest conduction path between the conductive core and the

conductive layer, wherein the distally facing surface is located distally relative to the shortest conduction path.

379. The system of Claim 377, wherein the sensor comprises a conductive core and a conductive layer configured to enable the system to apply a voltage between the conductive core and the conductive layer to measure an analyte indication,

wherein the sensor comprises a first electrical insulation layer located around a first section of the conductive core, and a second electrical insulation layer located around a second section of the conductive core,

wherein the conductive layer is located radially outward from the first insulation layer, and the first insulation layer is spaced apart from the second insulation layer to form a gap configured to enable the system to apply the voltage between the conductive core and the conductive layer, and

wherein the distally facing surface is located distally relative to the gap.

380. The system of any of Claims 377-379, wherein the distally facing surface is oriented within a range of plus or minus 20 degrees relative to perpendicular to the central axis.

381. A system substantially as shown and/or described in the specification and/or drawings.

382. A method substantially as shown and/or described in the specification and/or drawings.