Appartus and method for continuous real-time trace biomolecular sampling, analysis, and delivery
A system and method for transdermal sampling wherein at least one pair of sample electrodes is adapted to provide voltage pulses capable of creating capillary openings in a subject's stratum corneum. Methods for using a transdermal sampling system by creating capillary openings in a subject's stratum corneum via the application of a series of voltage pulses to the stratum corneum and contacting at least a portion of at least one of the sample electrodes with interstitial fluid from the capillary openings are also presented.
1. A device for transdermal sampling comprising:
a flexible substrate;
at least one pair of sample electrodes disposed on the flexible substrate;
an anchor layer covering at least a portion of at least one pair of sample electrodes;
a first pair of electrically conductive paths coupled to the at least one pair of sample electrodes;
a second pair of electrically conductive paths; and
at least one resistive element coupled to the second pair of electrically conductive paths, wherein:
the at least one resistive element is disposed proximate to the at least one pair of sample electrodes and configured to provide a sequence of thermal heating to generate a temperature sufficient to disrupt stratum corneum cells of a subject without damaging the stratum corneum cells to thereby allow interstitial fluid to pass through capillary openings formed through the stratum corneum cells and into contact with the at least one pair of sample electrodes.
2. The device according to claim 1 , wherein the anchor layer comprises an enzyme.
3. The device according to claim 2 , wherein the enzyme is selected from the group consisting of glucose oxidase and lactate oxidase.
4. The device according to claim 1 , wherein the at least one resistive element has a resistance of about 50 Ohms to about 200 Ohms.
5. The device according to claim 1 , wherein the sequence of thermal heating are created by applying voltage pulses to the at least one resistive element that are about 2 volts or less and for less than about 1 second.
6. The device according to claim 1 , wherein the flexible substrate comprises a cavity and the interstitial fluid is collected into the cavity.
7. The device according to claim 6 , wherein the at least one pair of sample electrodes are at least partially disposed in the cavity.
8. The device according to claim 1 , wherein the flexible substrate comprises a polymer.
9. The device according to claim 1 , wherein the flexible substrate comprises a multilayer polymeric metal laminate structure.
10. A method for transdermal sampling comprising:
affixing a device for transdermal sampling to the stratum corneum layer of a subject, wherein the device for transdermal sampling comprises:
a flexible substrate;
at least one pair of sample electrodes disposed on the flexible substrate;
an anchor layer covering at least a portion of at least one pair of sample electrodes;
a first pair of electrically conductive paths coupled to the at least one pair of sample electrodes;
a second pair of electrically conductive paths; and
at least one resistive element coupled to the second pair of electrically conductive paths, wherein:
the at least one resistive element is disposed proximate to the at least one pair of sample electrodes and configured to provide a sequence of thermal heating to generate a temperature sufficient to disrupt stratum corneum cells of a subject without damaging the stratum corneum cells to thereby allow interstitial fluid to pass through capillary openings formed through the stratum corneum cells and into contact with the at least one pair of sample electrodes; and
applying voltage pulses to the at least one resistive element via the second pair of electrically conductive paths to generate the temperature sufficient to disrupt the stratum corneum cells, wherein the voltage pulses are about 2 volts or less and are of a duration of 1 second or less.
11. The method according to claim 10 , wherein the anchor layer comprises an enzyme.
12. The method according to claim 11 , wherein the enzyme is selected from the group consisting of glucose oxidase and lactate oxidase.
13. The method according to claim 10 , wherein the at least one resistive element has a resistance of about 50 Ohms to about 200 Ohms.
14. The method according to claim 10 further comprising:
measuring an electrical property generated across at least one pair of sample electrodes; and
correlating the measured electrical property to a biological condition.
15. The method according to claim 14 , further comprising
delivering a material from a cavity within the device for transdermal sampling to the interstitial fluid.
16. The method according to claim 15 , further comprising analyzing the interstitial fluid for efficacy of the material.
17. The method according to claim 14 , further comprising:
determining whether the correlated biological condition is normal; and
generating a signal when the correlated biological condition is abnormal.
18. The method according to claim 17 , wherein the determining whether the correlated biological condition is normal comprises comparing the correlated biological condition to a normal healthy baseline condition.
19. The method according to claim 14 , wherein the biological condition is related to the amount of a targeted bio-molecule present in the interstitial fluid, wherein the targeted bio molecule is selected from the group consisting of glucose and lactate.
20. The method according to claim 14 , wherein the electrical property is current.
21. The method according to claim 10 further comprising:
controlling the application of voltage pulses with a controller; and
communicating information between the controller and a remote device.