A biosensor is a device that uses a biological recognition process to detect the presence of a specific analyte in a sample. The biosensor may be used to measure the concentration of the analyte, or to monitor changes in the analyte concentration over time. The specific recognition process may be based on antibodies, enzymes, nucleic acids, or other molecules that are able to specifically bind to the analyte.
The first step in using a biosensor is to immobilize the biomolecule onto the surface of the sensor. This can be done by adsorption, covalent binding, or entrapment within a matrix. The next step is to bring the sample containing the analyte into contact with the surface of the sensor. If the analyte is present in sufficient concentration, it will bind to its specific binding partner on the surface of the sensor.
The third step is to detect this binding event. This can be done optically, electrochemically, or through some other means. Once binding has been detected, it can be quantified by measuring either signal intensity or changes in signal over time. In some cases it may also be possible to determine amount of analyte present by calculating how much bound and unbound species there is in solution..
Biosensors have many potential applications in both scientific research and clinical settings. They can be used for environmental monitoring, for detection of foodborne pathogens, and for diagnosis of disease states such as cancer and infectious diseases. Biosensors are also being developed for use in point-of-care devices such as glucometers and blood pressure monitors. With continued development, biosensors will likely find even more widespread use in both scientific and medical fields