Detection of biomarkers in sweat

1 . A wearable device for quantitatively detecting a biomarker in a sweat sample obtained from skin of a subject, the device comprising:

a microfluidic network comprising:

a reservoir filled with a carrier fluid containing a predetermined amount of a marker;

a sample collection chamber disposed downstream from the reservoir and adapted to contact the skin of the subject and collect a sweat sample;

a first sensor disposed downstream from the sample collection chamber and adapted to detect the marker, wherein the first sensor is adapted to measure concentration of the marker in the carrier fluid; and

a second sensor disposed downstream from the first sensor and adapted to detect the biomarker,

wherein the microfluidic network further comprises a recirculation channel extending from a section of the microfluidic network downstream from the first and second sensors to a section of the microfluidic network intermediate to the reservoir and the sample collection chamber.

2 . The device of claim 1 , wherein a membrane which is selective for the biomarker is disposed downstream from the sample collection chamber and upstream of the first sensor.

3 . The device of claim 1 , wherein the device is configured to detect the biomarker at a sweat flow rate of between 0.03 and 20 nL/min/gland.

4 . The device of claim 1 , wherein the marker comprises at least one of a dye, an inert colloidal particle, or an electrochemically detectable compound of predetermined concentration.

5 . The device of claim 1 , further comprising one or more pumps configured to pump the carrier fluid at a predetermined flow rate of from 10 nL/min to 60 nL/min.

6 . A method of using the wearable device of claim 1 in contact with skin of the subject to quantitatively detect the biomarker in the sweat sample from the subject, the method comprising:

pumping the carrier fluid containing the marker to the sample collection chamber of the wearable device, wherein the sample collection chamber is adapted to contact the skin of the subject and collect the sweat sample;

pumping the carrier fluid containing the marker and the sweat sample from the sample collection chamber to the first and second sensors;

acquiring data relating to concentration of the marker present in the carrier fluid from the first sensor;

acquiring data relating to the biomarker from the second sensor;

determining the concentration of the biomarker in the sweat sample based on the data from the first and second sensors, and

determining sweat flow rate based on the concentration of the marker in the carrier fluid.

7 . The method of claim 6 , comprising:

determining a flow rate of one or both of the carrier fluid and the sweat sample based on the acquired data from the first sensor.

8 . The method of claim 6 , comprising:

determining a concentration of the biomarker in the sweat sample based on the flow rate of one or both of the carrier fluid and the sweat sample.

9 . The method of claim 6 , wherein the biomarker comprises one or more of: Na+, K+, Cl−, urea, ethanol, glucose, lactate ions, ammonium ions or cortisol.

10 . The method of claim 6 , comprising:

acquiring physiological data on the subject from a physiological sensor; and

adjusting a flow rate of the carrier fluid based on the acquired physiological data.

11 . A system for quantitatively detecting a biomarker in a sweat sample obtained from skin of a subject, the system comprising:

a wearable device as claimed in claim 1 ; and

a processor configured to:

acquire data from the first sensor of the wearable device, wherein the data acquired from the first sensor comprises concentration of the marker in the carrier fluid;

acquire data from the second sensor of the wearable device; and

determine the concentration of the biomarker in the sweat sample based on the data from the first and second sensors, and

wherein the processor is configured to determine sweat flow rate based on the concentration of the marker in the carrier fluid.

12 . A computer program product comprising a non-transitory computer readable medium, the non-transitory computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a computer or a processor, the computer or processor is caused to perform the method as claimed in claim 6 .