Biosensors are analytical devices that combine a biological component with a physicochemical detector. They are used to detect chemical substances in a sample. The biological component, such as an enzyme or an antibody, interacts with the substance being tested, and the detector converts this interaction into a measurable signal.
The concept of a biosensor was first proposed by Leland C. Clark Jr. in 1956. He developed an electrode that could measure the amount of oxygen in the blood. This device, known as the Clark electrode, is considered to be the first biosensor.
Biosensors are used in a wide range of applications, including medical diagnostics, environmental monitoring, and food safety. For example, glucose monitors used by people with diabetes are a type of biosensor. The field of biosensors is rapidly growing, with new and more sophisticated devices being developed all the time.