Sensor unit, body fluid monitoring device and method for detecting an analyte

1 . A sensor unit for detecting an analyte in an aqueous medium, the sensor unit comprising:

a surface for receiving the aqueous medium thereon;

capture species for reversibly binding said analyte, the capture species being immobilized on the surface;

a detector for detecting, determining or assessing analyte bound to the capture species; and

an electrolysis assembly including:

at least three spatially separated electrically conductive areas, all disposed on the same surface on which the capture species are immobilized and which receives the aqueous medium; and

a power supply configured to implement:

a first setting in which a first voltage sufficient to electrolyse the aqueous medium received on the surface is supplied across a first pairwise combination of the at least three spatially separated electrically conductive areas; and

a second setting in which a second voltage sufficient to electrolyse the aqueous medium received on the surface is supplied across a second pairwise combination of the at least three spatially separated electrically conductive areas, the second pairwise combination being different from the first pairwise combination.

2 . The sensor unit according to claim 1 , wherein at least two of the at least three spatially separated electrically conductive areas are arranged relative to each other in an interdigitated configuration.

3 . The sensor unit according to claim 1 , wherein at least one of a magnitude and polarity of the second voltage supplied in the second setting is different from at least one of a magnitude and polarity of the first voltage supplied in the first setting.

4 . The sensor unit according to claim 1 , wherein the second pairwise combination of the at least three spatially separated electrically conductive areas are spaced further apart on the surface than the first pairwise combination of the at least three spatially separated electrically conductive areas.

5 . The sensor unit according to claim 1 , wherein the at least three spatially separated electrically conductive areas includes an array of conductive areas in which the spacing between adjacent conductive areas alternates between a larger separation and a smaller separation; and wherein said power supply is configured to supply the first voltage and the second voltage across adjacent conductive areas spaced by the larger separation, the adjacent conductive areas spaced by the smaller separation being of the same polarity as each other.

6 . The sensor unit according to claim 1 , wherein the at least three spatially separated electrically conductive areas include a grid of electrically conductive strips, the power supply being configured to implement: a first mode in which the first voltage sufficient to electrolyse the aqueous medium is supplied across parallel strips extending in a first direction; and a second mode in which the second voltage sufficient to electrolyse the aqueous medium is supplied across parallel strips extending in a second direction, the second direction being different from the first direction.

7 . The sensor unit of claim 6 , wherein the power supply is further configured to sequentially implement the first mode and the second mode.

8 . The sensor unit according to claim 6 , wherein the transducer includes at least one of a quartz crystal resonator detector and a surface plasmon detector.

9 . The sensor unit according to claim 1 , wherein the power supply is configured to switch a polarity of the first voltage across the at least three spatially separated electrically conductive areas.

10 . The sensor unit according to claim 1 , wherein the detector includes a transducer.

11 . The sensor unit according to claim 10 , wherein the transducer is arranged to transmit and/or receive electrical signals via at least one of the at least three spatially separated electrically conductive areas.

12 . The sensor unit according to claim 1 , wherein the at least three spatially separated electrically conductive areas include an optically transmissive material.

13 . The sensor unit according to claim 1 , further comprising: a controller configured to trigger the electrolysis assembly to electrolyse the aqueous medium in response to a trigger signal.

14 . The sensor unit according to claim 13 , wherein the controller includes a sensor signal variation module configured to generate a variation signal in response to a signal received from the detector, the trigger signal including the variation signal.

15 . The sensor unit according to claim 13 , further comprising: a further sensor for monitoring a body parameter, the further sensor being configured to generate an event signal in response to a change in said body parameter, wherein the trigger signal includes said event signal.

16 . The sensor unit according to claim 13 , wherein the controller includes a clock module configured to send a clock signal to the controller at predetermined intervals, the trigger signal including the clock signal.

17 . The sensor unit according to claim 14 , wherein the signal variation module is configured to generate the variation signal in response to saturation of the detector.

18 . A body fluid monitoring device for detecting an analyte in an aqueous medium produced by a body, the body fluid monitoring device comprising: the sensor unit according to claim 1 ; and a fluid collection assembly for supplying the aqueous medium to the surface of the sensor unit.

19 . The body fluid monitoring device of claim 18 , wherein the body fluid monitoring device is a sweat monitoring device.

20 . A method for detecting an analyte in an aqueous medium, the method comprising:

providing capture species immobilized on a surface;

receiving the aqueous medium on the surface such that the analyte binds to the capture species;

detecting, determining or assessing the analyte bound to the capture species; and

subsequent to detecting, determining or assessing the analyte bound to the capture species, releasing the analyte from the capture species by electrolysing the aqueous medium received on the surface,

wherein the electrolysing includes:

supplying a first voltage sufficient to electrolyse the aqueous medium across a first pairwise combination of at least three spatially separated electrically conductive areas, all disposed on the same surface on which the capture species are immobilized and which receives the aqueous medium, and

supplying a second voltage sufficient to electrolyse the aqueous medium across a second pairwise combination of the at least three spatially separated electrically conductive areas, the second pairwise combination being different from the first pairwise combination.