Sensor

1. A sensor comprising:

a sensing region;

a porous barrier layer; and

a reactive oxygen species (ROS)-quenching agent formed on or in the barrier layer;

wherein the sensing region of the sensor defines one or more openings to allow an analyte in a bodily fluid sample to enter the sensing region;

wherein the barrier layer is disposed across the one or more openings to allow the analyte to enter the sensing region through the barrier layer such that the analyte comes into contact with the ROS-quenching agent;

wherein the barrier layer has an ROS-quenching activity sufficient to quench a solution of H 2 O 2 having a concentration of 10 ppm; and

wherein the sensor is configured such that fluid passing through the barrier layer is in contact with the ROS-quenching agent throughout the time the fluid is moving through the barrier layer.

2. The sensor of claim 1 , wherein the ROS-quenching agent comprises platinum.

3. The sensor of claim 2 , wherein the ROS-quenching agent comprises platinum in the form of nanoparticles.

4. The sensor of claim 1 , wherein an entire sensing region, or an entire surface of the sensor that comes into contact with the sample, is coated or sheathed with the barrier layer.

5. The sensor of claim 1 , wherein the barrier layer comprises polypropylene hollow fibres.

6. The sensor of claim 1 , wherein the sensing region is provided on a support material.

7. The sensor of claim 1 , wherein the barrier layer is provided over the entire sensing region or is provided on only part of the sensing region.

8. A sensor comprising:

a sensing region; and

a porous barrier layer comprising an ROS-quenching agent;

wherein the sensing region of the sensor defines one or more openings to allow an analyte in a bodily fluid sample to enter the sensing region; and

wherein the barrier layer is disposed across the one or more openings to allow the analyte to enter the sensing region through the barrier layer such that the analyte comes into contact with the ROS-quenching agent;

wherein the barrier layer has an ROS-quenching activity sufficient to quench a solution of H 2 O 2 having a concentration of at least 10 ppm; and

wherein the sensor is configured such that fluid passing through the barrier layer is in contact with the ROS-quenching agent throughout the time the fluid is moving through the barrier layer.

9. The sensor of claim 8 , wherein the barrier layer is impregnated with the ROS-quenching agent.

10. The sensor of claim 8 , wherein the barrier layer comprises platinum in the form of nanoparticles.

11. The sensor of claim 8 , wherein the barrier layer is applied directly onto the sensing region.

12. The sensor of claim 8 , wherein the barrier layer substantially does not cause depletion of analyte.

13. The sensor of claim 8 , wherein sensing region comprises a receptor and a fluorophore that are bound to one another and to a polymeric matrix.

14. The sensor of claim 8 , wherein the sensing region is provided on a support material.

15. The sensor of claim 8 , wherein the barrier layer defines pores that have a pore size ranging from about 1 nm to 1 μm and an aspect ratio of at least 100.

16. The sensor of claim 8 , wherein the barrier layer defines pores, the pores each having a length, and the ROS-quenching agent is within the pores of the barrier layer and is distributed along the length of the pores.

17. The sensor of claim 8 , wherein the barrier layer is a layer formed by vapour deposition of the ROS-quenching agent.

18. The sensor of claim 8 , wherein the barrier layer does not allow materials of molecular weight 6,000 or higher to pass through.

19. The sensor of claim 8 , wherein the ROS-quenching agent is present at a loading of 0.01 to 5 wt % of the barrier layer.

20. The sensor of claim 8 , wherein the barrier layer has an ROS-quenching activity sufficient to quench a solution of H 2 O 2 having a concentration of 100 ppm.

21. The sensor of claim 8 , wherein the barrier layer is provided over the entire sensing region or is provided on only part of the sensing region.

22. A sensor comprising:

a sensing region;

a porous barrier layer; and

an ROS-quenching agent formed on or in the barrier layer;

wherein the sensing region of the sensor defines one or more openings to allow an analyte in a bodily fluid sample to enter the sensing region;

wherein the barrier layer is disposed across the one or more openings to allow the analyte to enter the sensing region through the barrier layer such that the analyte comes into contact with the ROS-quenching agent; and

wherein the sensor is configured such that fluid passing through the barrier layer is in contact with the ROS-quenching agent throughout the time the fluid is moving through the barrier layer.