Use of pore forming proteins in nanobiotechnology

Pore forming proteins have long been recognised as attractive components of nanoscale sensing devices. In the body they are often targeted by drugs an d toxins which either open or block them. In changing from an open to a clo sed state or vice versa they modulate the flow of many ions per second such that individual channel closure events are easily measurable. Hence ion ch annels forming proteins or pore-forming proteins were the very first exampl e of single molecule detection in biology. Furthermore it is clear that: by addition of the correct ligand or in some cases by the application of a su itable transmembrane potential difference, the channels can be opened or cl osed at will. Hence these proteins are pre-existing nanoscale electronic sw itches which can transduce biological information into electrical data. Thi s paper describes how these proteins may be incorporated into biosensor typ e devices which have a high sensitivity for protein-protein interactions.