History of the Development of Biosensors
The development of biosensors began in 1950, when a biosensors with an oxygen electrode (sometimes described as Clark electrode) was developed by L. L. Clark in Cincinnati, USA to measure the dissolved oxygen in blood. Later, glucose oxidase enzyme in a gel was coated and immobilized on the oxygen electrode to measure blood sugar. Similarly, enzyme urease was used (in combination with an electrode specific for NH₄⁺⁺ ions) for measuring urea in body fluids like blood and urine. These two biosensors developed in early years of the history of biosensors made use of two different transducer technologies.

Whole cell biosensors were also developed during 1980s, making use of whole microbial cells or organelles. Similarly, small sensing organs like antennule have been used, to measure the level of various drugs or environmental toxicants. As mentioned above, receptor molecules located in cell membranes have also been isolated and used in biosensors.