Biosensors for ligand detection.

Publisher Summary Biosensors are such tools, which couple the ability of a biological sensor to precisely distinguish between inducer ligands, with a robust abiotic method of detection. The term biosensor can be used to describe devices for monitoring, recording, and transmitting information regarding physiological changes in living organisms. The most widely used are cellular and molecular biosensors. Cellular biosensors use reporter genes or proteins inside a cell, while molecular biosensors rely on a purified molecule, such as a protein. However, these definitions can become blurred as some molecular biosensors can be expressed inside a cell to generate a cellular biosensor. Another way of considering this is that cellular biosensors can be either induction biosensors or molecular biosensors, and one shall consider both these subclasses in this chapter. Induction biosensors rely on a ligand being detected by binding to a protein that induces expression of a reporter gene. The reporter gene codes for a protein that has an easily quantifiable activity, often relying on enzymatic and/or optical detection.