A device having a flow channel, wherein at least one flow-terminating interface is used to control the flow of liquid in the flow channel. The flow-terminating interface prevents the flow of the liquid beyond the interface. 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, and the base layer is separated from the cover layer by a spacer layer. The base layer, cover layer, and spacer layer define a flow channel into which a liquid sample is drawn therein and flows therethrough by means of capillary attraction. The flow of the sample is terminated by a flow-terminating interface positioned in the flow channel.