The antibodies are specific for the target molecule in the sample and will only bind to that target molecule. The capillary action in the lateral flow test causes the reactive molecules present in the sample (the antigen for Covid-19 tests, the hormone for pregnancy tests) to flow along the pad and interact with the antibodies present further up, and on the surface, of the pad. In essence, capillary action occurs when the water sticks more to the surface/walls than with other water molecules. In other words, water is sticky, and sticks to other water molecules and to surfaces/walls. This is the movement of water within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension. These operate via the test liquid 'flowing' along the surface of a pad, by a process known as capillary flow or action. The flow test detects a target molecule in the sample, an antigen in the case of Covid-19 and a hormone in the case of a pregnancy test. As many of us know, this approach is now used as a quick and accessible method for Covid-19 antigen testing and household pregnancy tests. These are devices that aim to detect the presence of a target substance/molecule in a liquid sample without the need for specialised and expensive equipment. In effect, achieving the 'flow state' for a given technology process.Īn example of such technology can be found in lateral flow tests. This allows them to avoid multiple, and potentially troublesome, start stop processes.

Often this involves scientists seeking to develop technology that allows chemicals and/or samples to flow effortlessly from one environment to another in a continuous fashion. In science, the use of flow and flowing systems is becoming an established strategy for technological developments. For them, the flow state is a place of supreme confidence, where the execution of their skill flows almost effortlessly from one action to the next, delivering a complete performance. Sportsmen, artists, and musicians might describe the flow state as being in 'the zone' or 'in flow'. Many of us will have experienced the 'flow state' at different times in our lives. Flow processes like those in Covid antigen and pregnancy tests, have become a major area of development in the pharmaceutical industry, writes PhD student Adam McCormack and Prof John Stephens, Department of Chemistry

Rapid lateral flow test