HK1176264A - Method and apparatus for insertion of a sensor - Google Patents

Description

Method and device for inserting a sensor

The application is a divisional application of Chinese patent application with the application number of 2006800421150(PCT/US2006/043737), having the application date of 2006, 11, 10 and entitled "method and device for inserting a sensor".

Cross Reference to Related Applications

Priority from U.S. provisional patent application No.60/735,732 entitled "Method and Apparatus for Insertion of a Sensor", filed 11/2005, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates generally to devices for mechanically delivering elongate devices through the skin and into the body to perform various medical or physiological functions. More particularly, the present invention relates to a method for safely and automatically placing a soft cannula biosensor or a flexible biosensor through the skin without the aid of a rigid or sharp introducer device and without the need for a sharp introducer device that is thus contaminated to be disposed of.

Background

There are several examples of medically useful devices that are mechanically elongated and flexible and are also inserted through the skin.

For example, sensors help detect certain conditions within a patient. Electrochemical sensors are commonly used to monitor blood glucose levels in the treatment of diabetes. In one approach, the enzyme-bound electrochemical sensor is fabricated on a small diameter wire. A second reference electrode is also fabricated around the line in the vicinity of the sense electrode. The sensor assembly is inserted through the skin such that the sensor assembly is surrounded by interstitial fluid. A portion of the sensor assembly exits the skin and remains outside the body where the sensing and reference electrodes can be electrically connected. The current from the sensor can be measured using a suitable electronic measuring device located outside the body to record and display the glucose value. These types of devices are described, for example, in U.S. Pat. No.5,965,380 to Heller et al and U.S. Pat. No.5,165,407 to Ward et al.

In addition to electrochemical glucose sensors, a wide variety of other electrochemical sensors have been developed to measure the chemistry of blood or other body fluids or materials. Electrochemical sensors generally utilize one or more electrochemical processes and electrical signals to measure a parameter. Other types of sensors include those that use optical techniques for measurement.

In other applications, the cannula and sensor combination is inserted through the skin to allow insulin to be introduced into the body as part of the artificial pancreas system. In these applications, an elongated (small cross-section) flexible device may provide a number of advantages over larger and more rigid devices. Patient comfort is increased, especially during long-term insertion, and trauma at the entry site is reduced. The flexible device may also adjust with the movement of the skin during physical activity, thereby increasing patient comfort. In many cases, these devices will remain inserted in the body for 5 to 7 days.

While the slender and flexible nature of these devices increases patient comfort, these devices are difficult to insert through the skin. Unlike typical hypodermic needles, these devices are too fragile and flexible to be simply pushed through the skin surface with normal force and speed. When the tip of such a device is forced against the skin, a force less than that required to achieve penetration of the skin will cause the device to bend and buckle. While in some cases the tip of the device may be sharpened for ease of penetration, this approach is generally not sufficient to ensure penetration, and some devices, such as tube-based devices, are not suitable for sharpening. Moreover, the sharpening process adds to the cost and complexity of production.

It will be appreciated by those familiar with the art that human skin has biomechanical properties that are affected by an outer layer that is relatively difficult to penetrate (i.e., the stratum corneum) and an inner layer that is more easily penetrated. These biomechanical properties make piercing the skin surface a major challenge in introducing a relatively fragile and elongated flexible device into the skin.

The prior art provides various methods for inserting such elongated flexible devices through the skin. In one instance, the device is placed coaxially within a hollow tube having a sharp end, such as a hypodermic needle or trocar. The needle is inserted through the skin and the device is located inside. In a second step, the needle is withdrawn, leaving the device behind for percutaneous access to the body. See, e.g., U.S. Pat. No.6,695,860 to Ward et al. The insertion process can be painful due to the large diameter of the needle, and creates a larger opening in the skin than would be necessary to simply pass the device through, thus increasing trauma and increasing the likelihood of infection.

In a variant of this method, the function of the device is incorporated into a thin needle, which must remain inserted in the skin. The needle provides additional mechanical strength and a sharpened tip to aid in piercing the skin. However, this approach also increases patient discomfort for the duration of the insertion due to its larger size and rigidity. See, e.g., U.S. patent No.6,501,976.

Furthermore, the presence of rigid needles imposes mechanical constraints on the size and shape of the device housing that is attached to the skin surface from which the device exits the skin. The needle must be disposed of as a biohazard "sharp" because it can transmit disease if it accidentally punctures the skin of another person after use in device insertion.

Disclosure of Invention

According to an aspect of the present invention, there is provided an insertion device for inserting a flexible analyte sensor into skin, the insertion device comprising:

a guide structure partially housed in a housing and adapted to provide axial support for the flexible analyte sensor, the guide structure having an outlet and partially extending out of the housing and being arranged to provide tension to the skin when the guide structure is pressed against the skin; and

an injection actuation device associated with the guide structure, the injection actuation device having:

a mechanism adapted to apply a high speed motive force to the flexible analyte sensor such that when the high speed motive force is applied to the flexible analyte sensor, the flexible analyte sensor moves at least partially through and independent of the guide structure and at least partially through the outlet such that only the flexible analyte sensor is inserted into the skin.

Preferably, the guide structure is a tube having a circular diameter.

Preferably, the guide structure is a curved guide structure.

Preferably, the curved guide structure is a curved hollow tube having a circular cross-section.

According to another aspect of the present invention, there is provided an analyte sensor assembly comprising:

a flexible analyte sensor having a first end and a second end, the second end configured to be inserted into skin;

a guide coupled to the first end of the flexible analyte sensor; and

a plurality of electrical contact elements coupled to the flexible analyte sensor and extending out of the guide, wherein the plurality of electrical contact elements are configured to electrically couple to one or more contact pads on an associated housing.

Preferably, the electrical contact element comprises a lead.

Preferably, the electrical contact element is insert molded into the guide.

Preferably, the electrical contact element is soldered to the flexible analyte sensor.

Preferably, the guide is arranged to fit within a guide structure located within the housing.

Preferably, the guide provides an impact surface for applying high speed power applied to insert the flexible analyte sensor into the skin.

Drawings

Embodiments of the present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals refer to like structural elements. Embodiments of the present invention are illustrated by way of example only and not by way of limitation in the figures of the accompanying drawings.

FIG. 1 shows a block diagram of an insertion device according to an embodiment of the invention;

FIG. 2A illustrates an embodiment of an electrochemical glucose sensor fabricated on a length of thin, flexible wire, according to an embodiment of the present invention;

FIG. 2B shows a cross-sectional view of an electrochemical sensor according to an embodiment of the present invention as it might appear when inserted into the skin;

FIG. 3A shows an insertion device in which an electrochemical sensor is inserted using a piston and spring combination, according to an embodiment of the invention;

FIG. 3B shows an insertion device according to an embodiment of the present invention, wherein the sensor may be initially withdrawn from the skin and initially brought into contact with the piston;

FIG. 4 illustrates an embodiment of the present invention with a simplified guide support structure;

FIG. 5A illustrates an embodiment of the present invention wherein the insertion device includes a transmitter cover and a sensor base;

FIG. 5B illustrates one embodiment of the present invention prior to attachment of the transmitter cover and sensor base;

FIG. 6A illustrates an embodiment of the present invention in which components of the sensor base are exposed to be visible;

FIG. 6B illustrates an embodiment of the invention in which only a portion of the components of the sensor base are exposed to be visible;

FIG. 6C shows a cross-sectional view of a sensor base according to an embodiment of the invention;

FIG. 7A shows a guidance concept according to one embodiment of the invention, wherein the sensor is guided with 3 plastic guides;

FIG. 7B illustrates a guidance concept according to one embodiment of the invention, wherein the sensor has attached two metal guides, which may double as a conductor;

FIG. 7C shows a guidance concept in which the resilient contact may mate with a metal guide doubling as a conductor;

FIG. 8 illustrates an embodiment of the invention in which energy stored in a bent sensor is used to power the sensor;

FIG. 9A shows an embodiment of the present invention in which a linear solenoid is used to power the sensor;

FIG. 9B shows an embodiment of the present invention in which a rotary solenoid is used to power the sensor;

FIG. 10 shows an embodiment of the present invention in which CO₂The gas storage cylinder is used for providing power for the sensor;

FIG. 11 shows an embodiment of the invention in which an air pump and piston are used to power the sensor;

FIG. 12 shows an embodiment of the invention in which mechanical springs are used to power the sensors and actuation is controlled by separate bow springs;

FIG. 13A shows an embodiment of the present invention in which a mechanical spring and slider combination is used to power the sensor;

FIG. 13B shows a cross-sectional view of one embodiment of the present invention in which a mechanical spring and slider combination is used to power the sensor;

FIG. 14 illustrates an embodiment of the present invention in which a set of mechanical springs and a shear member (shearmember) are used to control and power the sensors;

FIGS. 15A and 15B illustrate an embodiment of the invention in which electrical connection of the sensor is made via wires that are insert molded and soldered onto the conductive regions of the sensor;

FIG. 16A shows an exploded view of an embodiment of the present invention utilizing canted coil spring probe terminals for making electrical contact to the sensor;

FIG. 16B shows an assembled view of an embodiment of the present invention utilizing canted coil spring probe terminals for making electrical contact to the sensor;

FIG. 17A illustrates an embodiment of the present invention utilizing a paper guide structure to secure the sensor prior to insertion and to guide the sensor during insertion; and

FIG. 17B shows a view of one embodiment of the present invention after sensor insertion, where a paper guide structure has been employed to guide the sensor during insertion.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of embodiments in accordance with the present invention is defined by the appended claims and their equivalents.

Various operations may be described as multiple discrete operations in turn, in a manner that is helpful in understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations are order dependent.

The description (including the claims) may use perspective-based descriptions such as up/down, front/back, and top/bottom. These descriptions are merely used to facilitate the discussion and are not intended to limit the application of embodiments of the present invention.

For the purposes of the present invention, the expression "A/B" means A or B. For the purposes of the present invention, the expression "in the form of A and/or B" means "(A), (B) or (A and B)". For the purposes of the present invention, a statement in the form of "at least one of A, B and C" means "(A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C)". For purposes of the present invention, a statement in the form of "(a) B" means "(B) or (AB)", i.e., a is an optional element.

The description may use the phrases "in one embodiment" or "in multiple embodiments," which may both refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present invention, are synonymous.

For the purposes of describing embodiments of the present invention and the appended claims, the term "high speed dynamic force" refers to a force sufficient to drive a thin, flexible medical device into an animal's skin, which includes an outer layer that is relatively difficult to penetrate, i.e., the stratum corneum, and an inner layer that is more easily penetrated, without substantially bending or deforming the sensor, such as a force of about 0.5N/mm to 10N/mm. It will be apparent to those skilled in the art that the force necessary to drive a thin flexible medical device into the skin of an animal may be increased if the medical device encounters resistance not provided by the surface of the animal's skin but, for example, by scar tissue or frictional resistance created by a guide structure or tube through which the medical device must pass. The term "high speed motive force" includes the force necessary to drive a thin, flexible medical device into the skin of an animal in situations where the medical device may encounter such other resistance. In other words, the term "high speed motive force" includes any amount of motive force necessary to be applied to a thin, flexible medical device such that the sum of all forces acting on the medical device when the motive force is applied is sufficient to drive it into the skin of the animal.

The term "actuator" refers to any of a variety of electric, hydraulic, magnetic, pneumatic, or other devices that can move or control something. The term "solenoid actuator" refers to various electromechanical devices that convert electrical energy into linear or rotary motion. The term "trigger" means any of a variety of electrical, hydraulic, magnetic, pneumatic, or other devices that initiate a process or reaction. The term "bushing (sabot)" refers to a thick disc having a central hole.

For the purposes of describing embodiments of the present invention and in the appended claims, the term "axial support" refers to supporting or bracing an elongated, relatively straight object against a force vector acting perpendicular to an imaginary line passing longitudinally through the device when a motive force is applied to the object; such support or bearing is sufficient to prevent or reduce curling, folding or bending of the straight elongated object; or the support or bearing may be sufficient to return the object to a relatively straight configuration after minimal bending, such that the object substantially retains its original shape in the presence of minimal curling, folding, or bending.

For the purposes of describing embodiments of the present invention and in the appended claims, the term "associated with" means that one object, element or feature is joined, connected or in close proximity to another object, element or feature and is in communication therewith. For example, as shown in fig. 1, structure 102 can apply a high-speed motive force to analyte sensor 108 such that analyte sensor 108 moves through guide structure 106. Thus, the structure 102 is adjacent to the guide structure 106 and in communication with the guide structure 106, thereby "associating" with the guide structure 106.

In another embodiment shown in fig. 3A, a spring 307 may depress the piston 305 toward the sensor 301 and may drive the sensor 301 through the guide structure 303. Thus, the piston 305 and the spring 307 are in communication with the guide structure 303, and thus "associated" with the guide structure 303. The piston 305 and spring 307 may or may not be in physical contact with the guide structure 303, and may or may not be in contact in the rest position. Further, in fig. 3, since the spring 307 is connected to the piston 305, the spring 307 is associated with the piston 305.

In another embodiment shown in fig. 6A, the slider 605 is coupled to the guide structure 601 and the insertion spring 603 may force the slider 605 to move over the top of the guide structure 601. Thus, both the insertion spring 603 and the slider 605 are associated with the curved guide structure 601.

In yet another embodiment, shown in FIG. 10, the CO₂The gas cartridge 1001 can release CO₂The gas enters a branch tube (pilot) 1003 which allows the gas to pass through an internal valve (not shown) and into a hollow pin 1009 which may force the rod 1011 to strike a sensor (not shown) for insertion. Thus, CO₂The gas cartridge 1001 is in communication with and thus "associated with" a sensor (not shown).

For the purposes of describing embodiments of the present invention and in the appended claims, the term "guide" refers to a device that at least partially axially surrounds an analyte sensor and is adapted to fit inside the guide structure such that the guide structure at least partially occupies at least a portion of the space between the sensor and the guide structure during, before, and/or after insertion. The guide may provide axial support and/or assist the sensor in passing through the guide structure. Exemplary guides include bushings, plastic spirals, rectangular metal guides, open cell foam cylinders, and thin plastic disks. It will be appreciated by those of ordinary skill in the art that the guide may be made of many different materials and formed to have various geometries that may or may not correspond to the geometry of the guide structure.

For the purposes of describing embodiments of the present invention and in the appended claims, the term "electrical network" refers to circuits and devices in any desired structural relationship suitable for receiving, in part, an electrical signal from an associated sensor and optionally passing another signal, for example, to an external electronic monitoring unit responsive to the sensor signal. The circuit and other devices may or may not include printed circuit boards, cabled or wired systems, and the like. The signal transmission may be performed in the air using electromagnetic waves such as RF communication, or data may be read using inductive coupling. In other embodiments, the transmission may be over a wire or via another direct connection.

As shown in FIG. 1, one embodiment of the invention may include a mechanism 102, the mechanism 102 adapted to generate a high-speed motive force coupled to a guide structure 106, the guide structure 106 adapted to insert an analyte sensor 108. The mechanism 102 may be controlled by a trigger 114. In various embodiments of the present invention, analyte sensor 108 may be driven through the guide structure and out guide structure opening 112 by the high speed motive force generated by mechanism 102. In fig. 1, the guide structure opening 112 is shown flush with the edge of the housing 110. However, in various embodiments, the guide structure opening may be disposed outside of the housing 110 or nested within a larger opening of the housing 110.

In various embodiments, the guide structure may be a hollow tube having a circular cross-section. In various embodiments, the guide structure may be linear. In various embodiments, the guide structure may be curved to allow a motive force to be applied to the sensor in a direction that is not perpendicular to the skin into which the sensor is to be inserted. In various embodiments, the guide structure may be a curved hollow tube having a circular cross-section.

In various embodiments, the edge of the housing 110 where the opening 112 is located may be placed flush against the skin prior to insertion. Placing the edge of the housing 110 flush against the skin can create tension on the skin surface, which can facilitate insertion of the sensor without bending or deflecting the sensor. In embodiments where the guide structure 112 extends beyond the surface of the housing 110, it may be that the pressure of the guide structure 112 against the skin provides tension to the skin.

FIG. 2A shows an analyte sensor 200 that can be inserted according to various embodiments of the invention. In fig. 2A, the analyte sensor 200 is an electrochemical glucose sensor fabricated on a length of thin, flexible wire. A reference or ground electrode 205 and a sensing electrode 207 may be incorporated into the analyte sensor 200. The small diameter end 201 (proximal end) of the sensor 200 may be inserted through the skin. In one embodiment, this diameter may be about 0.25mm or less. In one embodiment, the diameter of the sensor 200 at the large diameter end (distal end) is increased by the addition of a steel tube sleeve 203, which can increase its rigidity and facilitate electrical connection. In some embodiments, the larger portion may be, for example, about 0.5mm in diameter. In one embodiment, the larger diameter portion of the sensor may remain outside the body after insertion. Figure 2B shows a cross-sectional view of the sensor after insertion into the skin. In some embodiments, a sensor 200 that is 10 to 20mm (e.g., about 15 mm) long may be implanted under the skin.

In various embodiments, a sensor inserted according to an embodiment of the present invention may be rigid or flexible. In some embodiments, flexible sensors are sensors that can flex repeatedly over a period of time (e.g., 3 to 7 days or more) without breaking, such as the type of flex experienced by sensors implanted subcutaneously in the human body during normal motion. In one embodiment, the flexible sensor may flex hundreds or thousands of times without breaking.

Figure 3A shows an insertion device according to one embodiment of the present invention. The sensor 301 may be placed into a guide structure 303 within the insertion device 300. In one embodiment, the guide structure 303 may allow the larger diameter end 302 of the sensor 301 to pass freely while providing axial support. Although there is more clearance between the sensor 301 and the interior of the guide structure 303 at the smaller diameter end 304, the guide structure 303 may also provide some axial support for the smaller diameter end 304 of the sensor 301. In one embodiment, the guide structure 303 may provide axial support for the sensor to successfully drive the sensor 301 into the skin.

The insertion device 300 may also contain a plunger 305, a compression spring 307, and a release mechanism consisting of a spring 311 and a pin 313. In preparation for sensor insertion, the piston 305 may be withdrawn against the spring 307 using the handle 309, thereby creating tension in the spring 307. A release mechanism holds the piston 305 in place. To implant sensor 301, pin 313 may be forced through slot 315 into the body of piston 305, thereby compressing spring 311, releasing piston 305, and allowing spring 307 to depress piston 305 along barrel 321 of insertion device 300 to strike large diameter end 302 of sensor 301. The piston 305 may drive the sensor into position in the skin 317. After insertion, the insertion device 300 may be withdrawn over the end of the sensor 301 without disturbing the position of the sensor 301 in the skin 317.

In one embodiment, appropriate electrical connections may be made after the insertion device 300 is withdrawn. In an alternative embodiment, the insertion device 300 may be integrated with a sensing device or associated housing having various electrical components, including electrical connections to the sensor 301. In such an embodiment, the electrical device may be connected to the sensor 301 prior to insertion and, after insertion, the insertion device 300 may be withdrawn by manipulation through the guide structure 303 and/or a slot present in the insertion device 300. In other words, the guide structure 303 and/or the insertion device 300 may be configured with a slot (straight or curved) so that either device may be disengaged from association with the sensor 301 even when the sensor 301 is electrically connected to other electronics at its distal end (large diameter end).

Those skilled in the art will appreciate that there are many alternatives to the guide and support structure, spring, piston and release mechanism for supporting the sensor and providing controlled impact and actuation forces that accomplish the various objectives of the embodiments of the present invention.

It should also be understood that although a wire-based electrochemical glucose sensor may be used, a similarly shaped device, such as another sensor or a drug delivery device such as a small tube for dispensing insulin or another drug, may be substituted for the glucose sensor in embodiments of the present invention.

In one embodiment, the insertion mechanism may be used only once as part of a disposable assembly. In such embodiments, since the device may be equipped with a piston that has been withdrawn and a release mechanism that is set and ready for insertion, it may not be necessary to provide manual means for the user to withdraw the piston and set the release mechanism.

In order to pierce the skin without damaging the sensor, the insertion through the softer skin lining can be done with a higher initial impact of the sensor tip against the skin after a controlled driving force. Note that the embodiment of the insertion device shown in fig. 3A creates a space or distance between the withdrawn piston and the end of the sensor to be actuated.

In the embodiment shown in fig. 3A, the force of the spring may cause the piston to accelerate through this distance before striking the end of the sensor. The speed of the piston provides an additional initial impact to the sensor that helps drive the sensor quickly through the tough outer layer of skin. In one embodiment, only the force of the spring is sufficient to complete the insertion.

In other embodiments, a strong initial impact of the sensor tip against the skin may be achieved in other ways. For example, in another embodiment shown in fig. 3B, the sensor 301 may be initially withdrawn from the skin and may be initially in contact with the piston 310. In this embodiment, the sensor 301 may be accelerated along with the piston 310 before impacting the skin.

In further embodiments, the sensor may be accelerated only by a motive force to achieve a momentum that produces an impact sufficient to penetrate the skin.

It will be appreciated by those skilled in the art that in other embodiments of the invention, means other than springs may be utilized to provide high speed power. Some embodiments include an electromagnetic solenoid, providing an electric power supplyShape memory alloy spring for dynamic driving force, and related CO₂Gas storage cylinders, compressed air pumps, and the like.

Fig. 4 shows an embodiment of an insertion device 400 with a simplified curved guide support device. In one embodiment, prior to insertion, the sensor 401 is supported at its larger end 402. The thin distal end 404 of the sensor 401 follows a curved path during insertion. However, in this case, the guide structure 409 may be mainly constituted by a partially open area with a bend 403, which bend 403 may guide and support the sensor 401 only on that side of the sensor 401 which is located outside the radius of the arc formed by the sensor 401 during insertion. It will be appreciated by those skilled in the art that when an insertion force is applied, the sensor 401 may apply a radially outward force along the bend 403 against the support wall of the guide structure 409 of the insertion device 400. This radial force may tend to support and stabilize the sensor 401 without requiring a fully enclosed guide structure.

Another feature of the embodiment in fig. 4 is that the open area at the skin contacting side of the guide structure 409 may allow the sensor to be easily and completely detached from the insertion device 400 after insertion is completed. Further, in one embodiment, the open area may be large enough to accommodate other electrical connections and/or components associated with the sensor 401 before, during, and/or after insertion.

Fig. 5A illustrates an embodiment of the invention in which an assembled insertion device may include an emitter 502, a sensor base 504 (which may be disposable in one embodiment), and a probe trigger 506. In this embodiment, the sensor and means for supplying high speed power to the sensor (not shown) may be contained within the sensor base 504. In one embodiment, the sensor may be inserted by: the sensor is inserted into the skin by placing the bottom of the sensor base 504 on the skin and pressing (in a press-fit, snap-fit, or other type of structure) on top of the emitter 502 to move or in other words be triggered to cause the means for supplying high speed power within the sensor base 504 to impact the sensor.

The embodiment shown in fig. 5A may include disposable or reusable portions such as the sensor base 504 and the emitter 502. Thus, in one embodiment, a partially reusable device may be provided that includes a reusable transmitter element 502 and a disposable sensor base 504. In various embodiments, other electronics (batteries, processing components, etc.) may be provided in the emitter component 502 and/or the sensor base 504.

According to one embodiment of the invention, the transmitter means may comprise an electrical circuit which may comprise an electrical network adapted to receive an electrical signal from the associated sensor and to transmit another signal, for example to an external electronic monitoring unit responsive to the sensor signal. In various embodiments, an electrical network may include various devices in any desired structural relationship, whether the network has a printed circuit board, a cable, or a wired system. In one embodiment, signal transfer may be performed in the air using electromagnetic waves such as RF communication, or data may be read using inductive coupling. In other embodiments, the transfer may be by wire or via another direct connection.

In an embodiment of the invention shown in fig. 5B in an exploded state, sensing device 500 can be assembled by sliding emitter 502 into a recess 506 on sensor base 504. A recess 506 in the sensor base 504 aligns and secures the sensor base 504 and the transmitter 502 together. In one embodiment, the locking bolt 508 is secured to a locking edge 510 to provide additional securement.

In one embodiment, the emitter may be reusable, while the sensor base may be adapted to be disposed of after a single use. In other embodiments, both the sensor base and the transmitter may be reusable. In other embodiments, both the sensor base and the emitter may be adapted to be discarded.

In various embodiments of the present invention, a hand tool may be used to assemble the emitter and sensor base together. The hand tool may be used by first placing the transmitter upside down on the hand tool. The sensor base may be provided with and a strip-like strip and backing plate (backing card) located in position along the bottom of the sensor base and having a protective blister (bubble cap) on the opposite face. The blister may be removed from the sensor mount, which may then be placed on the slide of the hand tool. The backing plate may be used to align the sensor within the hand tool. Next, the slide can be pushed over the emitter to snap the emitter and sensor base together. In an alternative embodiment, the hand tool may have two parts hinged together rather than a slide. After assembly, the patch may be removed and the tool may be used to place the device on the patient's body. In various embodiments, the sensor may be inserted into the patient by pushing a tool to move a trigger to actuate an injection actuation device. The hand tool can be released by squeezing the release tab (tab). It will be apparent to one of ordinary skill in the art that different embodiments of hand tools may be used, or that hand tools may not be used in various embodiments.

In some embodiments, the means for supplying high speed power may be attached to the sensor base. In other embodiments, the means for supplying high speed power may be attached to the transmitter. In various embodiments, the means for supplying high speed power may be located in a separate handle that is not part of the sensor base or transmitter. In various embodiments, such a handle may be removed after insertion. Details of such a handle can be found in U.S. patent application No.11/468,673, which describes a device that uses a handle and also utilizes a trocar to provide power to insert a sensor. While the present invention is primarily directed to methods and devices for inserting sensors without the use of a trocar or related device, the details of U.S. patent application No.11/468,673 (including the handle) may be extended to various embodiments of the present invention.

FIG. 6A shows components of a sensor base 600 according to an embodiment of the invention. The curved guide structure 601 may be coupled to the insertion spring 603 via a slider 605, which slider 605 may receive the upper end of the curved probe (not shown). The wires 607 and 609 may be soldered to the sensor to make electrical contact. Thus, the slider 605 may provide a housing for insert molding to seal the terminals and provide protection for otherwise exposed probes.

The insert spring 603 may be attached to the outermost end of the slider 605 during manufacture and then pulled back beyond the outermost end of the slider 605. The slider 605 may be prevented from moving forward by two beams 611 (only one shown) protruding from the slider 605 and engaging the edges of a rectangular aperture 613 in the base surface 615 of the sensor base 600. In this way, the insertion spring 603 maintains potential energy and the slider 605 may remain stationary.

The battery leads 617 and 619 may be spot welded to the battery 621, for example, and the battery 621 may be secured in place using a potting compound or other suitable securing compound or mechanism. All four lead wires 607, 609, 617, 619 can be attached to a small wire spring 623 that can be insert molded into the connector assembly 625. A soft rubber gasket 627 may be attached to the periphery of the connector assembly 625 for sealing with a corresponding contact pad on the transmitter (not shown) once the transmitter is secured in place. The connection face of the connector assembly 625 is angled so that the contact and sealing features do not interfere during mating so that the total mating force does not act to attempt to separate the emitter and sensor base 600.

Fig. 6B shows an exploded view of some components of the sensor base 600. In this view, guide structure 601 is omitted, exposing probe 603 and a lift block (riser) 629 of trigger 631. In this embodiment of the invention, the jack-up block 629 may be pressed upward, thereby pushing the two rectangular beams 611 upward so that they slide against the forward edges of the rectangular apertures 613 (see fig. 6A) to be released. Once released, the insertion spring 603 is no longer blocked, allowing the slider 605 to move rapidly forward. Thus, the bent probe 633 will be inserted into the patient's skin through the bent guide structure and partially through an opening (not shown) in the sensor base.

In this embodiment of the invention, the trigger 631, and thus the jacking blocks 629, may be raised relative to the device by placing the device on the patient's skin and applying downward pressure.

Fig. 6C shows a cross-sectional view of the sensor base 600. The flip-flop 631 is shown more clearly here. A flex feature on the top of the trigger 631 can hold the probe 633 in place prior to insertion and can help guide the flexed probe 633 during insertion. When the trigger 631 is pushed upward during insertion, the gap 635 between the trigger 631 and the base surface 615 can be closed.

FIG. 7A illustrates a probe guidance concept according to one embodiment of the present invention. The sensor 701 is shown with a permanently attached top guide 703. In one embodiment of the invention, the top guide 703 may be insert molded onto the sensor 701. In another embodiment, the top guide 703 may be attached using an adhesive bond. In other embodiments, the top guide 703 may be ultrasonically welded. The lower guide 705 may be part of the housing (not shown) of the device. Upon insertion, the sensor 701 slides within a lower end guide 705 (which may be a molded feature of the housing). In another embodiment, the lower end guide 705 may be a separate piece that is bonded to the housing during manufacturing.

The lower guide 705 may be angled to allow the sensor 701 to be inserted into the skin at an angle other than 90 degrees to the skin. In other embodiments of the present invention, the sensor 701 may be inserted at other angles from 0 to 90 degrees (including 90 degrees).

The central bushing guide 707 may be free floating and remain generally centered on the sensor 701 as the sensor 701 is inserted into the skin. In other words, in one embodiment of the present invention, the central bushing guide 707 may be coupled to neither the sensor 701 nor the insertion device. The central bushing guide 707 may prevent the sensor 701 from buckling during insertion. All of the components in fig. 7 may remain with the device after insertion of the sensor 701.

Although the guidance concept in fig. 7A is shown with three guides, one of ordinary skill in the art will appreciate that more or less than three guides may be used to guide the sensor and prevent buckling. Although the guidance concept in fig. 7 is shown with three cylindrical guides, one of ordinary skill in the art will appreciate that other geometries may be used, including but not limited to rectangular geometries. In various embodiments, the shape and size of the guide may be configured to accommodate the shape and size of the guide structure.

Those of ordinary skill in the art will appreciate that the guide shown in fig. 7A may be produced from a variety of materials including, but not limited to, various plastics or metals.

In some embodiments of the invention, the central guide may be constructed of an open cell foam that can easily collapse during insertion and has virtually no resiliency after being compressed.

In another embodiment, the central guide may be a plastic screw with a central bore that serves to guide the probe and prevent buckling during insertion. The helix may collapse during insertion and occupy very little space after compression. The helix may be retained within the body of the device after insertion of the sensor. The manufacture of the plastic screw may be carried out by moulding or using equipment similar to a short screw pasta (rotini pasta) extruder.

In another embodiment of the invention, the central guide may be replaced by a set of thin plastic discs each having a central hole. The disc may guide the probe during insertion and prevent buckling. After insertion, the discs can be brought close to each other and occupy very little space after compression. In various embodiments of the invention, the tray may be made by molding or stamping a thin plastic sheet.

In the embodiment of the invention shown in fig. 7B, the top guide 709 and the central guide 711 may facilitate making electrical connections with the sensor 701, as well as help guide the sensor 701 and prevent buckling during insertion. In these embodiments, the guide may be made of a suitable conductive material including any number of suitable metals. In one embodiment, the top guide 709 may be welded to the exposed core (not shown) of the sensor via the slot 713, while the central guide 711 may be welded to the silver cladding (not shown) via the slot 713. Welding the top guide 709 to the sensor 701 may form a permanent attachment to the sensor 701 and allow a mechanism for applying high speed power (not shown) to act directly on the top guide 709 during insertion.

Referring now to fig. 7C, fig. 7C shows a cross-sectional view of an embodiment of the sensor and guide design of fig. 7B placed into an insertion device, electrical contact between the device and guides 709 and 711 may be achieved by using a set of leaf spring contacts 713 built into the body of the device. After insertion, contact may occur near the end of travel of the sensor 701. In other embodiments, electrical contact between the top guide 709 and the central guide 711, respectively, may be made by bonding wires of the peel sensor 701.

Fig. 8 shows a cross-sectional view of the bottom of an insertion device according to an embodiment of the invention. The sensor 801 is shown as being arcuate and confined within the body of the device. The top curve of the arcuate sensor 801 may protrude slightly beyond the open opening 807. As shown in fig. 8, an open opening 807 is located on the bottom surface of the device (which surface is adapted for placement on the skin). The device may be placed against the skin of a patient (not shown) and pressed down. A force may be applied to the top of the bowed sensor 801 to force the sensor 801 to straighten, forcing the proximal tip/end of the sensor 801 into contact with the skin at a pressure sufficient to cause the sensor 801 to pierce the skin. To generate high speed power when straightened, the sensor 801 may contain a core material with sufficient elasticity to store sufficient energy when bent.

In various embodiments, the direct drive linear solenoid actuator design of fig. 9A may be used to provide high speed power to the sensor. In these embodiments, the solenoid 901 may be coupled to the body of the device with a support structure 909. The support structure 909 includes a cylindrical member 907 having a hollow core. The solenoid shaft 903 may be extended so that it also becomes the end of a direct impact sensor (not shown) and provides a high speed power thereto. In one embodiment, the solenoid shaft 903 may be partially located in the barrel 907. When power is applied to the solenoid 901, the shaft 903 may travel through the barrel 907 to provide high speed power to the sensor for insertion. After insertion, a return spring 905, located between the end of the barrel 907 and the shaft stop 911, may return the shaft to its position prior to insertion.

In various embodiments, the rotary solenoid actuator design of fig. 9B may be used to provide high speed power to the sensor. In these embodiments, the rotary solenoid 951 may be coupled to the body of the device using a support structure 967. The arm 953 may be attached to a rotating plate 957 of the solenoid and the distal end of the arm may be slotted and bent back on itself to provide an opening for engagement with a pin 959 attached to the top end of the rod 955. As soon as power is applied to the solenoid 951, the solenoid 951 rotates clockwise (as oriented in fig. 9B), which causes the rotating plate 957 to rotate and the pin 959 to move along the linear guide slot 961. Linear movement of the pin 959 may cause the associated rod 955 to move in a linear direction through a hollow barrel 965 that is part of the housing structure of the device. The bar 955 may then strike the end of the sensor (not shown) and provide high speed power for inserting the sensor.

In various embodiments, the lever may return to its original position when power is no longer applied to the solenoid. In various embodiments, a manufacturer may incorporate a spring into the solenoid to ensure that the solenoid will return to its rest position whenever power is not applied to the solenoid.

It should be understood by those of ordinary skill in the art that embodiments of the present invention utilizing solenoids are not limited to the configurations shown in fig. 9A and 9B. For example, the rotary solenoid embodiment shown in fig. 9B may incorporate a cam surface rather than a rotary arm connected to a rotary plate. Embodiments using a linear solenoid actuator as in FIG. 9A may incorporate intermediate members of various configurations to impact the end of the sensor, rather than utilizing an elongated solenoid shaft as shown in FIG. 9A.

FIG. 10 illustrates the use of CO in accordance with the present invention₂An embodiment of a gas cartridge. As shown, CO₂The head of the gas cartridge 1001 may be placed into a hole in the manifold 1003 and the CO tightened₂The nut behind the gas cartridge 1001 would be in contact with the CO₂The gas cartridge 1001 moves deeper into the branch pipe where a hollow pin (not shown) pierces the CO₂Gas cartridge 1001 and allowing compressed CO₂And entering the system. There are two internal stent lumens (not shown). One cavity is connected to CO₂A gas cartridge 1001 and another chamber is connected to a hollow pin 1009. A spring-loaded valve (not shown) may be provided between them to initially maintain back pressure from the gas cartridge 1001 and its associated manifold lumen. The internal valve (not shown) opens temporarily so long as the spring loaded striker 1007 is allowed to strike the valve head 1005 so that a quantity of gas can escape from the CO₂The branch lumen associated with the gas cartridge 1001 flows into the branch lumen associated with the hollow tube 1009. Gas may then enter hollow tube 1009 and force rod 1011 to move forward and strike a sensor (not shown) for insertion. When rod 1011 approaches the end of travel, exhaust port 1013 may travel over the end of hollow tube 1009, allowing CO to pass₂And (4) discharging. After insertion, the rod 1011 can be moved back to its original position using a return spring 1015.

Fig. 11 shows a cross-sectional view of an embodiment of the present invention using an air pump. The embodiment shown in FIG. 11 may use a CO similar to that previously discussed₂Gas storage bottleSimilar embodiment of the manifold system. The manifold is enclosed in a housing structure 1104. When lever arm 1101 is pulled upward, air may be drawn into a branch lumen associated with plunger 1105 via a one-way valve (not shown). Pushing down on lever arm 1101 moves connecting rod 1103, which is coupled to the shaft of plunger 1105, forcing the plunger into its associated manifold. The movement of the plunger 1105 into the branch tube may compress air drawn into the associated branch tube on the upward stroke of the lever arm 1101. When spring-loaded plunger 1109 is allowed to strike valve head 1111, an internal valve (not shown) is temporarily opened and compressed air can flow from the manifold lumen associated with plunger 1105 to the manifold lumen associated with hollow tube 1113. Gas may then enter hollow tube 1113 and force rod 1115 to move forward and strike a sensor (not shown) for insertion. As rod 1115 approaches the end of travel, an exhaust port (not shown) on the rod may travel past the end of hollow tube 1113, allowing compressed air to escape. After insertion, return spring 1117 may be used to move rod 1115 back to its initial position.

Fig. 12 shows an embodiment using a mechanical spring according to the present invention. In this embodiment, the bow spring 1205 may initially bow upward toward the button 1201 and may be placed in the actuator frame 1207 at a partial location along the length of the stem 1209. If the button 1201 is pressed, it may press a power spring 1203 against the bow spring 1205, at which time a cut-out in the bow spring 1205 may engage a slot cut into the stem 1209 to prevent the head of the stem 1209 from moving forward. In alternative embodiments, external ridges may be used in place of slots on the shaft 1209.

Under a predetermined force, the bow spring 1205 may exhibit an "oil can" effect, and its bow may immediately reverse direction. This action releases the lever 1209 from the spine cut into the bow spring 1205, and the accumulated force in the power spring 1203 can then drive the lever 1209 forward, and can then strike a sensor (not shown) with high speed power for insertion.

Fig. 13A shows a mechanical spring according to an embodiment of the present invention. The slider 1301 may be pulled back to the distal end of the support structure 1303, creating tension in the spring 1305 supported by the pin 1313. Referring now to fig. 13B, which shows a cross-sectional view of the mechanical spring actuator, it can be seen that the slider 1301 has an angled feature 1317, the feature 1317 resting on an angled surface at the top of the stem 1315. The slide 1301 may be held in place by a trigger mechanism (not shown). The rods 1315 can be attached to pins 1307 with each end of the pins 1307 being located within two angled slots 1309 (shown in fig. 13A) of the support structure 1303. When the trigger releases the slide 1301, the slide can move forward, causing the rod 1315 to be forced to move in a path parallel to the slot 1309 by the pin 37. Rod 1315 may then impact a sensor (not shown) to supply high speed power to facilitate insertion. The angled top feature of the rod 1315 may slide off the corresponding angled feature of the slider 1301 as the end of travel of the rod 1315 is approached, allowing the rod to return to its rest position using the force provided by the return spring 1311. When the slider 1301 is pulled back again, it can run along a cam surface (not shown) which guides it upwards out of the upper end of the rod and then falls back again behind it, ready for the next firing.

FIG. 14 shows a cross-sectional view of a mechanical spring impact device for providing high speed power to a sensor for insertion according to an embodiment of the present invention. When button 1401 is depressed, trigger arm 1403 may be driven forward. A small shear member 1405 at the opposite end of trigger arm 1403 may initially engage the tip of striker 1407, pulling striker 1407 away from rod 1411 and causing striker spring 1409 to compress and accumulate stored energy. As the workpiece (shear) moves closer to its end of travel, the striker 1407 may slide off the workpiece due to the difference in the angle of the respective directions of movement of the workpiece and the striker. At this point, the striker 1407 can move forward under the force provided by the compression striker spring 1409, impacting the stem 1411 and allowing the stem to impact a sensor (not shown) and provide high speed power to facilitate insertion.

The trigger arm 1403 may then be reversed towards its rest position with the force supplied by the return spring 1413. Also, the lever 1411 may be returned to its rest position using the force supplied by the return spring 1417. As the member rides over the top of striker 1407, the shear rotates to clear the upper end of striker 1407 and spring 1415 rotates the shear back to the position ready for the next insertion.

Fig. 15A shows a wiring scheme according to an embodiment of the present invention. The sensor 1501 is shown with a plastic bottom guide 1509 and a plastic center guide 1507. In one embodiment, lead 1503 may be soldered to sensor 1501 and then insert molded into top guide 1505. Referring now to fig. 15B, the opposite end of lead 1503 may be soldered to contact 1511 on the body of the device. An open slot 1513 in the guide structure may allow the lead 1503 to move unimpeded during sensor insertion.

Prior to insertion, the pad 1515 may be partially attached to the device by placing the pin 1521 partially into the receiver 1523. After insertion of the sensor, the pin 1521 may be fully pressed into the receiver 1523, which causes the shorting bar 1517 to contact the battery pads 1525 (only one shown) as the pad 1515 is fully pushed to its final position. In this way, the shorting bar 1517 may function to complete and conduct the power circuit of the device.

Fig. 16A and 16B illustrate a sensor electrical terminal assembly according to an embodiment of the present invention. Fig. 16A shows an exploded view of this embodiment. The sensor 1601 may be fitted with a set of canted coil springs 1603 positioned over the upper conductive area of the sensor 1601. Two small rectangular housings 1605 may be placed over the springs and two rectangular portions of the metal sheet 1607 may be placed in corresponding slots on the rectangular housings 1605. Referring now to fig. 16B, two leads 1609 extending from canted coil springs 1603 may be passed through slots 1611 in rectangular housing 1605 and spot welded to the two portions of sheet metal 1607. This terminal assembly may be moved down an insertion channel (not shown) after insertion of the sensor. At the bottom of the insertion channel, a rectangular metal sheet 1607 may be in contact with two shaped spring members protruding from the channel (not shown).

An alternative is to reverse the orientation of the lower portions of the two canted coil springs so that their leads come out of the lower ends of the springs. In this way, the assembly can be insert molded into a rectangular housing to form a sealed connection.

Another embodiment includes pre-positioning the terminal assembly at the bottom of the insertion passage. In this embodiment, the sensor may pass through the assembly and make electrical contact with the spring after insertion.

Fig. 17A and 17B illustrate a paper guide structure according to an embodiment of the present invention. As shown in fig. 17A, paper 1703 may be placed in a rectangular slot 1705 and over sensor 1701. Paper 1703 may be used to secure paper 1703 prior to insertion and to guide sensor 1701 during insertion. Prior to insertion, the sensor 1701 may be located at a depth (e.g., half the diameter of the sensor 1701) within the recess 1711 (visible in fig. 17B).

Referring now to fig. 17B, during insertion, an injection actuation device (not shown) may push against the upper end of sensor 1701 and move within rectangular slot 1705. As it moves, the injection actuation device may separate the paper 1703 along the slot 1711, creating a paper break 1709 when the sensor 1701 is inserted. After insertion, the conductive region of sensor 1701 may be brought into contact with leaf spring 1707, thereby electrically coupling sensor 1701 to the device.

In alternative embodiments, other similar materials, such as a thin plastic covering, may be substituted for the paper.

In embodiments of the invention, the additional components may be housed in one or more separate modules that are coupled (e.g., snapped onto, wired to, or connected by wireless communication) to the insertion device. For example, individual modules may contain memory components, battery components, transmitters, receivers, transceivers, processors, and/or display components, among others.

In embodiments of the invention, sensors having substantially the same cross-section may be used. Alternatively, in embodiments of the invention, sensors with varying cross-sections may be used. In various embodiments, the sensor may be cylindrical, square, rectangular, or the like. In one embodiment, the sensor may be a line sensor. In one embodiment, the sensor may be flexible.

Although certain embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that embodiments in accordance with the present invention may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments in accordance with the present invention be limited only by the claims and the equivalents thereof.

Claims (10)

1. An insertion device for inserting a flexible analyte sensor into skin, the insertion device comprising:

a guide structure partially housed in a housing and adapted to provide axial support for the flexible analyte sensor, the guide structure having an outlet and partially extending out of the housing and being arranged to provide tension to the skin when the guide structure is pressed against the skin; and

an injection actuation device associated with the guide structure, the injection actuation device having:

a mechanism adapted to apply a high speed motive force to the flexible analyte sensor such that when the high speed motive force is applied to the flexible analyte sensor, the flexible analyte sensor moves at least partially through and independent of the guide structure and at least partially through the outlet such that only the flexible analyte sensor is inserted into the skin.

2. The insertion device of claim 1, wherein the guide structure is a tube having a circular diameter.

3. The insertion device of claim 1, wherein the guide structure is a curved guide structure.

4. An insertion device according to claim 3, wherein the curved guide structure is a curved hollow tube having a circular cross-section.

5. An analyte sensor assembly, comprising:

a flexible analyte sensor having a first end and a second end, the second end configured to be inserted into skin;

a guide coupled to the first end of the flexible analyte sensor; and

a plurality of electrical contact elements coupled to the flexible analyte sensor and extending out of the guide, wherein the plurality of electrical contact elements are configured to electrically couple to one or more contact pads on an associated housing.

6. The analyte sensor assembly of claim 5, wherein the electrical contact element comprises a lead.

7. The analyte sensor assembly of claim 5, wherein the electrical contact element is insert molded into the guide.

8. The analyte sensor assembly of claim 5, wherein the electrical contact element is soldered to the flexible analyte sensor.

9. The analyte sensor assembly of claim 5, wherein the guide is configured to fit within a guide structure located within the housing.

10. The analyte sensor assembly of claim 5, wherein the guide provides an impact surface for applying high speed power applied to insert the flexible analyte sensor into skin.