Biosensors: clinical requirements and scientific promise

Biosensors are currently very fashionable, even though they are not new! - an enzyme electrode being described almost 20 years ago by Updike and Hicks in 1967. The aim of this review is to put into perspective why biosensors are needed in clinical medicine and to describe some of the research that is being performed to develop such devices for, in particular, 'in vivo' applications.