INTERSTITIAL FLUID CAPTURE DEVICE AND METHOD OF MEASURING ELECTROLYTE LEVELS USING SAME

Abstract

Embodiments of the inventive concept include an interstitial fluid capture device configured to capture an interstitial fluid sample from the mouth of a user, an electrolyte measurement kit including said device, and a method for measuring electrolyte levels using said device. An exemplary device includes a main body portion configured for placement in the mouth of a user, the main body portion including a reservoir containing a hypertonic solution and having an opening that is sealed by a semipermeable membrane that permits a sample of interstitial fluid from the mouth of the user to be drawn through the membrane and into the solution reservoir. Various analyses may be performed on the captured interstitial fluid sample after removal of the device, including but not limited to, the assessment of one or more electrolyte levels through the use of various test strips or other techniques.

Claims

1. An interstitial fluid capture device, comprising: a main body portion configured for temporary retention in the mouth of a user; a solution reservoir located within the main body portion, the reservoir forming an opening along a fluid extraction side of the main body portion; a hypertonic solution residing in the solution reservoir of the main body portion; and a semipermeable membrane covering the solution reservoir opening and sealing the hypertonic solution within the solution reservoir, the semipermeable membrane constructed from a material that will permit interstitial fluid from mouth tissue of the user to be drawn through the semipermeable membrane and into the solution reservoir during use.

2. The interstitial fluid capture device of claim 1, wherein the main body portion is configured for temporary retention in a position selected from the group consisting of between the teeth and lip of the user, between the teeth and cheek of the user, and under the tongue of the user.

3. The interstitial fluid capture device of claim 1, wherein the main body portion is configured such that, when properly positioned in the mouth of the user, the fluid extraction side of the main body portion and the solution reservoir opening thereof will face the lip of the user, and the semipermeable membrane will contact the lip of the user.

4. The interstitial fluid capture device of claim 1, wherein the main body portion comprises medical grade silicone.

5. The interstitial fluid capture device of claim 1, wherein the hypertonic solution is hypertonic relative to the interstitial fluid typically present in human mouth tissue.

6. The interstitial fluid capture device of claim 1, wherein the semipermeable membrane is a dialysis membrane.

7. The interstitial fluid capture device of claim 1, wherein the semipermeable membrane is sealed to the main body portion by an overlying ring of material.

8. The interstitial fluid capture device of claim 1, wherein the semipermeable membrane is sealed to the main body portion by a technique selected from the group consisting of overmolding of the edges of the semipermeable membrane by the main body portion material, and bonding of the semipermeable membrane to the main body portion material.

9. The interstitial fluid capture device of claim 1, wherein the main body portion includes an area of thinned material that overlies at least a portion of the solution reservoir along a non-fluid extraction side of the main body portion to facilitate penetration of the solution reservoir.

10. An electrolyte measurement kit, comprising: an interstitial fluid capture device, the interstitial fluid capture device further comprising: a main body portion configured for temporary retention in the mouth of a user, a solution reservoir located within the main body portion, the reservoir forming an opening along a fluid extraction side of the main body portion, a hypertonic solution residing in the solution reservoir of the main body portion, and a semipermeable membrane covering the solution reservoir opening and sealing the hypertonic solution within the solution reservoir, the semipermeable membrane constructed from a material that will permit interstitial fluid from the mouth of the user to be drawn through the semipermeable membrane and into the solution reservoir during use; and at least one electrolyte test strip configured to measure the level of at least one electrolyte present in a sample of interstitial fluid captured by the interstitial fluid capture device.

11. The kit of claim 10, wherein the main body portion of the interstitial fluid capture device is configured for temporary retention in a position selected from the group consisting of between the teeth and lip of the user, between the teeth and cheek of the user, and under the tongue of the user.

12. The kit of claim 10, wherein a plurality of different types of test strips are present.

13. The kit of claim 12, wherein the plurality of different types of test strips are configured to measure the level of one or more electrolytes selected from the group comprising chloride, bicarbonate, calcium, sodium, potassium, magnesium.

14. The kit of claim 10, wherein the at least one test strip is configured to penetrate the main body portion to allow for insertion of the test strip into the solution reservoir.

15. A method of assessing at least one electrolyte level of a user, comprising: providing an interstitial fluid capture device, the interstitial fluid capture device further comprising: a main body portion configured for temporary retention in the mouth of a user, a solution reservoir located within the main body portion, the reservoir forming an opening along a fluid extraction side of the main body portion, a hypertonic solution residing in the solution reservoir of the main body portion, and a semipermeable membrane covering the solution reservoir opening and sealing the hypertonic solution within the solution reservoir, the semipermeable membrane constructed from a material that will permit interstitial fluid from the mouth of the user to be drawn through the semipermeable membrane and into the solution reservoir during use; placing the interstitial fluid capture device in the mouth of the user; retaining the interstitial fluid capture device in the mouth of the user for some amount of time sufficient to permit a sufficient sample of interstitial fluid to be drawn from the mouth of the user, through the semipermeable membrane, and into the solution reservoir; removing the interstitial fluid capture device from the mouth of the user; and inserting at least one electrolyte test strip into the solution reservoir of the interstitial fluid capture device, the at least one electrolyte test strip configured to measure the level of at least one electrolyte present in the sample of interstitial fluid present in the solution reservoir.

16. The method of claim 15, wherein the main body portion of the interstitial fluid capture device is temporary retained in a position selected from the group consisting of between the teeth and lip of the user, between the teeth and cheek of the user, and under the tongue of the user.

17. The method of claim 15, wherein a plurality of different types of test strips are used to measure a plurality of different electrolytes present in the interstitial fluid sample.

18. The method of claim 17, wherein the plurality of different types of test strips are used to measure the level of one or more electrolytes selected from the group comprising chloride, bicarbonate, calcium, sodium, potassium, magnesium.

19. The method of claim 15, further comprising comparing an electrolyte level reading obtained through use of the at least one test strip to an expected and/or proper electrolyte level or range of electrolyte levels.

20. The method of claim 15, further comprising recording a baseline electrolyte level obtained from the interstitial fluid sample captured by the interstitial fluid capture device, and comparing subsequent electrolyte level measurements obtained from additional interstitial fluid capture devices to the baseline measurement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following descriptions of the drawings and exemplary embodiments, like reference numerals across the several views refer to identical or equivalent features, and:

[0023] FIG. 1A is a front view of one exemplary embodiment of an interstitial fluid capture device according to the inventive concept;

[0024] FIG. 1B is a rear view of the exemplary interstitial fluid capture device shown in FIG. 1A;

[0025] FIG. 2 is a front view of one exemplary embodiment of a main body portion of the exemplary interstitial fluid capture device shown in FIGS. 1A-1B;

[0026] FIG. 3 represents installation of a semipermeable membrane over the solution reservoir that is located within the exemplary main body portion shown in FIG. 2;

[0027] FIG. 4A represents the semipermeable membrane of FIG. 3 installed to the main body portion shown in FIG. 2 and covering the solution reservoir thereof;

[0028] FIG. 4B is an enlarged view of a portion of FIG. 4A, indicating sealing of the edges of the semipermeable membrane by the material forming the main body portion; and

[0029] FIG. 5 is a top view of an exemplary interstitial fluid capture device comprising a main body portion with a hypertonic solution-filled internal reservoir sealed along a front surface thereof by a semipermeable membrane as variously represented in in the preceding drawing figures, and indicating proper orientation of an exemplary interstitial fluid capture device when located in the mouth of a user.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0030] As previously explained, an interstitial fluid capture device according to the general inventive concept is an oral appliance that is designed for placement in the mouth of a user and operable to draw and retain interstitial fluid from the lip (or other mouth area) of the user for testing purposes. One exemplary embodiment of such an interstitial fluid capture device 5 is illustrated in the front view of FIG. 1A and the rear view of FIG. 1B.

[0031] The exemplary interstitial fluid capture device 5 includes a main body portion 10. The main body portion 10 may be specially shaped and dimensioned to facilitate placement and retention within the mouth of a user, or the main body portion may be of more basic shape, such as but not limited to, a tubular shape. In the exemplary embodiment shown, the main body portion 10 is designed for temporary retention between the teeth and lip of a user. However, other exemplary main body portions of other device embodiments may be designed for alternative placement within the mouth, such as without limitation, between the teeth and cheek, or under the tongue. An exemplary main body portion, such as the main body portion 10, is preferably comprised of an elastomeric material, such as but not limited to, medical grade silicone. The main body portion of an exemplary interstitial fluid capture device may also be comprised of other materials appropriate for oral application.

[0032] As may be best observed in FIG. 2, the main body portion 10 includes an internal solution reservoir 15 that opens along the front (extraction or lip contacting) surface of the main body portion. Within the reservoir 15 is placed an amount of a highly concentrated, high molecular weight solution 20 that is hypertonic relative to the interstitial fluid normally present in a human lip. The hypertonic solution 20 is sealed within the reservoir 15 along the front surface of the main body portion 10 by a semipermeable (e.g., dialysis) membrane 25 that is installed thereto, as also represented in FIG. 3. Although the semipermeable membrane 25 of the exemplary interstitial fluid capture device 5 represented in FIG. 3 is a substantially flat membrane, a semipermeable membrane of tubular form (e.g., dialysis tubing) may be utilized in other exemplary interstitial fluid capture device embodiments.

[0033] FIGS. 4A-4B illustrate one technique by which the semipermeable membrane 25 may be sealed to the main body portion 10 so as to prevent leakage of the extraction solution 20 from the reservoir 15. Particularly, and as best illustrated in FIG. 4B, during manufacture of the exemplary interstitial fluid capture device 5, the material of which the main body portion 10 is comprised is molded or otherwise formed so as to overlap the edges of the semipermeable membrane 25. For example, the edges of the semipermeable membrane 25 may be embedded in or encapsulated by the material forming the main body portion 10 or may be trapped between layers thereof. Alternatively, a ring of the same material forming the main body portion (or another suitable material) may be overlaid upon the semipermeable membrane 25 to seal the edges thereof to the main body portion 10. Further, sealing of the semipermeable membrane 25 to the main body portion (and corresponding sealing of the solution reservoir 15) may be accomplished by other techniques in other device embodiments, such as without limitation, bonding the edges of the semipermeable membrane to the main body portion.

[0034] FIG. 5 depicts proper orientation of the exemplary interstitial fluid capture device 5 within the mouth of a user. Specifically, the rear of the interstitial fluid capture device 5 resides along the teeth of the user, while the front of the interstitial fluid capture device faces the inner surface of the user's lip. At least for ease of use and comfort, the exemplary interstitial fluid capture device 5 is contemplated as being designed for location between the lower lip and teeth of a user during use. However, it is to be understood that an exemplary interstitial fluid capture device may instead be designed for location between the upper lip and teeth of a user during use (or, as described above, against the cheek or under the tongue in other embodiments).

[0035] With the exemplary interstitial fluid capture device 5 positioned in the mouth of a user as described above, interstitial fluid (not saliva) will be automatically drawn from the user's lip through the semipermeable membrane 25 and into the solution reservoir 15, as indicated by the arrows in FIG. 5. As would be understood by one of skill in the art, this drawing of interstitial fluid from the lip of the user, through the dialysis membrane 25 and into the solution reservoir 15, occurs because of the hypertonic nature of the extraction solution 20. That is, interstitial fluid from the lip is drawn into the solution reservoir 15 by means of osmosis resulting from the solute concentration on the hypertonic solution side of the semipermeable membrane 25 and the solute concentration of the fluids in the user's lip on the opposite side of the semipermeable membrane, being unequal.

[0036] Upon sufficient extraction of interstitial fluid, the exemplary interstitial fluid capture device 5 may be removed from the mouth of the user. The interstitial fluid-hypertonic solution mixture remains within the solution reservoir 15 of the main body portion 10 until the reservoir is deliberately accessed for assessment purposes or otherwise. Once desired assessment, etc., of the captured interstitial fluid or other use of the exemplary interstitial fluid capture device 5 is complete, the device may be discarded.

[0037] In some exemplary embodiments, one or more interstitial fluid capture devices may be packaged with other items. For example, an interstitial fluid capture device or a collection of multiple interstitial fluid capture devices may be provided along with information that allows a user to compare an electrolyte reading obtained through use of an exemplary interstitial fluid capture device to an expected and/or proper electrolyte level or range of electrolyte levels. Such information may be provided in the form of numerical data, tables, charts, graphs, and/or any other form of information.

[0038] Similarly, exemplary embodiments may package one or more interstitial fluid capture devices with one or more other items that facilitate recording of a baseline electrolyte(s) measurement(s) obtained through use of an interstitial fluid capture device and subsequent recording and/or comparison of the baseline measurement(s) with future electrolyte measurements obtained through use of additional interstitial fluid capture devices.

[0039] Interstitial fluid capture devices according to the inventive concept may also form a part of a kit, such as for purposes of illustration and not limitation, a kit for assessing/monitoring electrolyte levels. Whatever the particular purpose, a kit that includes an interstitial fluid capture device may also include other elements related to use of the device(s). In the case of a kit for assessing/monitoring electrolyte levels, for example, the kit may also include one or more easy to use test strips for measuring the level of one or more types of electrolytes. The existence and use of test strips for measuring electrolytes such as, without limitation, chloride, bicarbonate, calcium, sodium, potassium, magnesium would be familiar to one of skill in the art.

[0040] To use the exemplary interstitial fluid capture device 5, a user places the device in his/her mouth between the teeth and the lip, such that the dialysis membrane is in contact with the lip. The device is retained in this position for a period of time that is sufficient to permit the device to extract an adequate amount of interstitial fluid from the user's lip in the manner explained above. The amount of time that an exemplary interstitial fluid capture device should be retained in the mouth of a user may be indicated on packaging, instructions, etc., provided with the device. Once the interstitial fluid capture device has been retained in the mouth of the user for a sufficient period of time, it may be thereafter removed.

[0041] The solution reservoir within the main body portion may subsequently be accessed to reach the interstitial fluid sample contained therein. Access to the solution reservoir may be accomplished for example, by penetration with the appropriate end of an electrolyte or other test strip, by penetration with a needle or similar implement, or the reservoir may simply be cut open. To facilitate access to the solution reservoir of an exemplary interstitial fluid capture device, an area of the main body portion that overlies at least a portion of the solution reservoir along a non-extraction side of the device may be thinner than other areas of the main body portion to allow for easier penetration by a test strip or other implement.

[0042] With respect to electrolyte measurement, for example, an electrolyte test strip may be inserted into the reservoir to contact the test strip with the extraction solution-interstitial fluid mixture, and the test strip may thereafter be read or otherwise analyzed to assess the level of the electrolyte for which the test strip is designed (e.g., chloride). Other test strips may be simultaneously or subsequently inserted into the solution reservoir to similarly determine the level of other electrolytes (e.g., bicarbonate, sodium, calcium, potassium, magnesium) present in the interstitial fluid sample. Once assessment, testing, etc., of the interstitial fluid sample has been completed, the entire device may be discarded.

[0043] Exemplary embodiments of an interstitial fluid capture device according to the inventive concept allow a user to easily, comfortably and cost effectively capture an interstitial fluid sample. Exemplary embodiments of an interstitial fluid capture device according to the inventive concept also allow a user to easily assess/monitor electrolyte levels or levels of other biomarkers and eliminate the need for drawing a blood sample or collecting a urine sample as is commonly required by known electrolyte measurement techniques. Exemplary embodiments of an interstitial fluid capture device according to the inventive concept further allow a user to assess/monitor electrolyte levels (or conduct other tests) without the need to engage a physician or other appropriate technician or send a blood or urine specimen to a lab, which reduces the costs to the user.

[0044] While the inventive concept and exemplary embodiments thereof have been described above with respect to use on and by human users, it is to be understood that exemplary embodiments may also be designed for and used to capture interstitial fluid from other mammals (e.g., dogs, horses)—at least those having a mouth structure to which a main body portion can be acceptably inserted and temporarily retained. As with the human uses described above, interstitial fluid captured from other animals may be used for various purposes, including but not limited to assessing/monitoring electrolyte levels.

[0045] While certain embodiments of the inventive concept are described in detail above, the scope of the inventive concept is not considered limited by such disclosure, and modifications are possible without departing from the spirit of the inventive concept as evidenced by the following claims: