Biosensors : A Survey Report Saraju P. Mohanty Dept. of Comp. Sc. and Engg. University of South Florida Tampa, FL 33620, USA. smohanty@csee.usf.edu November 24, 2001 Abstract A biosensor is a sensing device made up of a com- bination of a specific biological element and a transducer. The ”specific biological element” rec- ognizes a specific analyte and the changes in the biomolecule are usually converted into electrical signal (which is in turn calibrated to a certain scale) by a transducer. Aim of this survey work is to discuss the various biosensors available for dif- ferent biosensing applications. Initially, the survey focuses on the basics of biosensing devices which can serve as introductory tutorial for the readers who are new to this field. Later, the survey high- lights the technicalities of few biosensors in great detail. The survey ends with brief discussion on the major difficulties the biosensor research com- munities normally encounter. 1 Introduction The history of biosensors started in the year 1962 with the development of enzyme electrodes by the scientist Leland C. Clark. Since then the re- search communities from various fields like VLSI, physics, chemistry, material science, and so on, have come together to develop more sophisticated, reliable and matured biosensing devices for appli- cations in the fields of medicine, agriculture, and biotechnology, etc. What is a biosensor ? Various definitions and ter- minologies are used depending on the field of ap- plications. Depending on the field of applications biosensors are known as : immunosensors, op- trodes, chemical canaries, resonant mirrors, glu- cometers, biochips, biocomputers, and so on. Two generalized definitions of biosensors can be found in [2, 4]. Authors in [2] define it as : ”a biosen- sor is a chemical sensing device in which a bio- logically derived recognition entity is coupled to a transducer, to allow the quantitative development of some complex biochemical parameter”. Ac- cording to the authors [4] : ”a biosensor is a an- alytical device incorporating a deliberate and inti- mate combination of a specific biological element (that creates a recognition event) and a physical el- ement (that transduces the recognition event)”. The name ”biosensor” signifies that the device is a combination of two parts : bio-element sensor-element. The bio-element may be an enzyme, antibody, antigen, living cells, tissues, etc. The large variety of sensor-elements includes electric current, elec- 1