ABSTRACT
The purpose of a sensor is to provide information about its external environment. Sensors are common throughout our lives. Sensors such as thermometers and pressure gauges give us information about the physical environment. Sensors such as pH meters give us information about their chemical environment. Biosensors are a specific class of sensing device that make use of the interaction of biological or biochemical species as the means of sensing the environment. Biological systems are characterized by very selective interactions between molecules-for example, enzymes and their substrates, antibodies and their antigens, cell receptors and their ligands. The other important characteristic of these interactions is their affinity. These biochemical species interact strongly with one another, endowing great sensitivity. These two properties-selectivity and sensitivityare the main characteristics that make biosensors such powerful analytical devices.
