DEVICES FOR INTEGRATED, REPEATED, PROLONGED, AND/OR RELIABLE SWEAT STIMULATION AND BIOSENSING

• US 20150112164A1
• Filed: 10/17/2014
• Published: 04/23/2015
• Est. Priority Date: 10/18/2013
• Status: Active Grant

• Current Assignee: University of Cincinnati
• Original Assignee: University of Cincinnati
• Inventors: Heikenfeld, Jason C., Sonner, Zachary Cole
• Granted Patent: US 10,182,795 B2
• Time in Patent Office: Days
• US Class Current: 600/307
• CPC Class Codes: A61B 10/0064 for taking sweat or sebum samples measuring sweat production A61B5/4266
• CPC Class Codes: A61B 2010/0009 Testing for drug or alcohol abuse
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/168 Fluid filled sensor housings
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/14521 using means for promoting sweat production, e.g. heating the skin measuring sweat secretion A61B5/4266
• CPC Class Codes: A61B 5/1491 Heated applicators
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/4266 sweat secretion
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61M 2202/092 Sweat glands
• CPC Class Codes: A61N 1/325 for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body electrodes for external use A61N1/0428

Abstract

A sweat sensing device includes a plurality of sweat collection pads communicating with a sensor. Each of the pads is activated by a timing circuit which allows one or more of the pads to be activated at a selected time and subsequent deactivated after a defined period of time. This allows for selective collection of sweat from a plurality of pads over a prolonged period of time. An impedance measuring circuit can be employed to determine if one or more of the pads becomes disconnected, in order to avoid irritation. Further, the devices can use a common microfluidic device which both transports sweat activating substance, such as pilocarpine, to the surface of the skin and directs sweat away from the skin to a sensing device.

Claims

1. An apparatus to measure or collect sweat over an extended period of time, comprising:

at least one sweat stimulation pad;

a timing circuit adapted to selectively activate and deactivate said at least one sweat stimulation pad for one or more limited periods of time.

2. The apparatus of claim 1 comprising a plurality of sweat stimulation pads, each selectively operable by said circuit.

3. The apparatus of claim 2 comprising a plurality of sweat stimulation pads, wherein at least two pads have different sweat stimulation rates.

4. The apparatus of claim 2 wherein each of said pads includes a sweat flow path leading to a sensor.

5. The apparatus of claim 4 wherein each sweat flow path leads to the same sensor.

6. The apparatus of claim 4 wherein each flow path leads to a separate sensor.

7. The apparatus of claim 4 wherein at least one flow path includes a gate selectively operable to allow sweat flow only during a selected time.

8. The apparatus of claim 1 including an electrical sensor associated with said sweat stimulation pad, said sensor adapted to detect direct or indirect contact between said pad and skin, which permits deactivation of said pad.

9. The apparatus of claim 8 wherein said electrical sensor detects impedance.

10. The apparatus of claim 1 including at least one sensor which receives sweat resulting from stimulation by said stimulation pad wherein said sensor and said stimulation pad are not fluidically coupled.

14. The apparatus of claim 1 wherein the stimulated area for at least one pad is less than 50 mm² to reduce irritation perceived by the user of the apparatus.

15. The apparatus of claim 1 wherein the stimulated area for at least one pad is less than 10 mm² to reduce irritation perceived by the user of the apparatus.

16. The apparatus of claim 1 wherein the stimulated area for at least one pad is less than 2 mm² to reduce irritation perceived by the user of the apparatus.

17. The apparatus of claim 2 wherein each of said collection pads includes a gate operable to prevent flow of sweat to a sensor.

11. A method of generating and monitoring sweat over a prolonged period of time comprising:

electrically generating sweat at a plurality of separate discrete locations on a skin surface;

wherein separate locations are activated at a plurality of time periods and generated sweat from each location is directed to one or more sensors.

12. The method of claim 11 further comprising detecting skin contact, wherein sweat activation can be stopped if inadequate skin contact is detected.

13. The method of claim 11 wherein flow of sweat from an area to said sensor is activated only at selected times.

18. A sweat collector including an electrical stimulator and an electrical sensor adapted to detect inadequate skin contact to prevent burns.

19. A sweat stimulating and transport device capable of both transporting sweat away from the skin and transporting sweat-stimulating substances to the skin comprising:

a sweat stimulating component and at least one additional component, wherein the additional component is at least one of a sweat transporting component, a shared microfluidic component, and a sensor.

20. The device of claim 19 wherein the transport of sweat stimulating substances is at least partially achieved by iontophoresis.

21. The device of claim 19 wherein the transport of sweat stimulating substances is at least partially achieved by diffusion from a high concentration to a low concentration.

22. The device of claim 19 wherein the at least one additional component is separated from a reservoir of sweat stimulating substance by a fluid flow-limiting layer.

23. The device of claim 19 wherein at least one sensor is contained in fluidic contact with the shared microfluidic component.

24. The device of claim 19 wherein the at least one additional component is separated by a membrane from a reservoir containing a sweat stimulating substance, wherein said membrane selectively transports the sweat stimulating substance.

25. The device of claim 19 wherein the at least one additional component is separated by a membrane from a reservoir containing a sweat stimulating substance, wherein said membrane limits flow of fluid or diffusion of solutes.

26. The device of claim 19 wherein the at least one additional component is separated from a reservoir of sweat stimulating substance by a membrane with a higher porosity to the sweat stimulating substance than one or more of the solutes in sweat that are to be sensed.

27. The device of claim 19 wherein the at least one additional component is separated from a reservoir of sweat stimulating substance by a membrane with a lower electrical impedance than the electrical impedance of skin.

29. The device of claim 27 wherein the substance to reduce irritation, inflammation, or pain, is delivered iontophoretically.

30. The device of claim 27 wherein the substance to reduce irritation, inflammation, or pain, is delivered iontophoretically using the same voltage polarity to deliver the sweat stimulant.

28. A sweat stimulating and sensing device comprising:

at least one of a sweat-stimulating substance, a substance to reduce irritation, inflammation, or pain, caused by said sweat stimulation and a sweat reducing substance.