Abstract: A device having a flow channel, wherein a layer of mesh is adhered to a surface forming a wall of a flow channel, but the layer of mesh is of such dimensions that the layer of mesh does not contact those portions of the device where electrochemical reactions occur and electrons flow. In one aspect, the invention provides a sensor, such as, for example, a biosensor, in the form of a strip, the sensor being suitable for electrochemical or optical measurement. The sensor comprises a base layer and a cover layer having a layer of mesh adhered thereto, and the base layer is separated from the cover layer by a spacer layer. The base layer, the cover layer having a layer of mesh adhered thereto, and the spacer layer define a flow channel into which a liquid sample is drawn therein and flows therethrough by means of wicking.