SYSTEM AND METHOD FOR DETECTING SKIN PENETRATION

• US 20110105942A1
• Filed: 08/24/2007
• Published: 05/05/2011
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Agency For Science Technology and Research
• Original Assignee: Agency For Science Technology and Research
• Inventors: Lim, Chee Yen, Lai, Szu Cheng
• Granted Patent: US 8,583,225 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150954 Means for the detection of operative contact with patient, e.g. by temperature sensitive sensor
• CPC Class Codes: A61B 5/150984 Microneedles or microblades
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61B 5/685 Microneedles
• CPC Class Codes: A61M 37/0015 by using microneedles
• CPC Class Codes: A61M 5/46 having means for controlling depth of insertion

Abstract

A system and method for detecting skin penetration. The system comprises an invasive component for penetrating the skin; a dummy electrode for making contact with the surface of the skin; at least one penetrating electrode disposed in the invasive component; and a Wheatstone bridge circuit; wherein a resistance across the dummy electrode and the penetrating electrode constitutes one of the resistive legs of the Wheatstone bridge circuit and skin penetration of the invasive component is detected based on a differential output voltage from the Wheatstone bridge circuit.

Claims

1. A system for detecting skin penetration, the system comprising:

an invasive component for penetrating the skin;

a dummy electrode for making contact with the surface of the skin;

at least one penetrating electrode disposed in the invasive component; and

a Wheatstone bridge circuit;

wherein a resistance across the dummy electrode and the penetrating electrode constitutes one of the resistive legs of the Wheatstone bridge circuit and skin penetration of the invasive component is detected based on a differential output voltage from the Wheatstone bridge circuit.

2. The system as claimed in claim 1, further comprising a first pair of reference electrodes for making contact with the surface of the skin, wherein a resistance across the first pair of reference electrodes constitutes the mirroring resistive leg, with respect to ground, of the Wheatstone bridge circuit.

3. The system as claimed in claim 2, wherein one of the reference electrodes is the dummy electrode.

4. The system as claimed in claim 2, further comprising second and third pairs of reference electrode, each for making contact with the surface of the skin, wherein respective resistances across the second and third pairs of reference electrodes constitute the remaining resistive legs of the Wheatstone bridge circuit respectively.

5. The system as claimed in claim 1, wherein a plurality of penetrating electrodes are disposed in the invasive component.

6. The system as claimed in claim 5, wherein resistances across the dummy electrode and the respective penetrating electrodes are multiplexed across one of the resistive legs of the Wheatstone and a penetration depth of the invasive component is detected based on differential output voltages from the Wheatstone bridge circuit for the respective resistances across the dummy electrode and the respective penetrating electrodes.

7. The system as claimed in claim 1, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin is disposed on a skin-contact face of the lancing device.

8. The system as claimed in claim 2, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin and the first pair of reference electrodes are disposed on a skin-contact face of the lancing device.

9. The system as claimed in claim 4, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin and the first, second, and third pairs of reference electrodes are disposed on a skin-contact face of the lancing device.

10. The system as claimed in claim 1, wherein the invasive component comprises a hollow or solid microneedle.

11. The system as claimed in claim 1, wherein the invasive component comprises a conductive microneedle.

12. The system as claimed in claim 1, wherein the invasive component comprises a non-conductive microneedle.

13. The system as claimed in claim 12, wherein the invasive component comprises a plastic microneedle.

14. The system as claimed in claim 1, further comprising means for indicating skin penetration of the invasive component based on the differential output voltage from the Wheatstone bridge circuit.

15. The system as claimed in claim 1, further comprising means for displaying the penetration depth of the invasive component based on the differential output voltages from the Wheatstone bridge circuit.

16. The system as claimed in claim 7, wherein the reference and/or dummy electrodes are disposed around an opening of a distal end of the lancing device.

17. A method for detecting skin penetration, the method comprising the steps of:

penetrating the skin with an invasive component wherein at least one penetrating electrode is disposed in the invasive component;

making contact between a dummy electrode and the surface of the skin;

applying a resistance across the dummy electrode and the penetrating electrode as one of the resistive legs of a Wheatstone bridge circuit; and

detecting skin penetration of the invasive component based on a differential output voltage from the Wheatstone bridge circuit.

18. The method as claimed in claim 17, further comprising the steps of:

making contact with the surface of the skin with a first pair of reference electrodes; and

applying a resistance across the first pair of reference electrodes as the mirroring resistive leg, with respect to ground, of the Wheatstone bridge circuit.

19. The method as claimed in claim 18, wherein one of the reference electrodes is the dummy electrode.

20. The method as claimed in claim 18, further comprising the steps of:

making contact with the surface of the skin with second and third pairs of reference electrode, and

applying respective resistances across the second and third pairs of reference electrodes as the remaining resistive legs of the Wheatstone bridge circuit respectively.

21. The method as claimed in claim 17, wherein a plurality of penetrating electrodes are disposed in the invasive component.

22. The method as claimed in claim 21, wherein resistances across the dummy electrode and the respective penetrating electrodes are multiplexed across one of the resistive legs of the Wheatstone and a penetration depth of the invasive component is detected based on differential output voltages from the Wheatstone bridge circuit for the respective resistances across the dummy electrode and the respective penetrating electrodes.

23. The method as claimed in claim 17, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin is disposed on a skin-contact face of the lancing device.

24. The method as claimed in claim 18, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin and the first pair of reference electrodes are disposed on a skin-contact face of the lancing device.

25. The method as claimed in claim 20, wherein the invasive component comprises a microneedle disposed in a lancing device, and the dummy electrode for making contact with the surface of the skin and the first, second, and third pairs of reference electrodes are disposed on a skin-contact face of the lancing device.

26. The method as claimed in claim 17, wherein the invasive component comprises a hollow or solid microneedle.

27. The method as claimed in claim 17, wherein the invasive component comprises a conductive microneedle.

28. The method as claimed in claim 17, wherein the invasive component comprises a non-conductive microneedle.

29. The method as claimed in claim 28, wherein the invasive component comprises a plastic microneedle.

30. The method as claimed in claim 17, further comprising the step of:

indicating skin penetration of the invasive component based on the differential output voltage from the Wheatstone bridge circuit.

31. The method as claimed in claim 17, further comprising the step of:

displaying the penetration depth of the invasive component based on the differential output voltages from the Wheatstone bridge circuit.