Since the development of the glucose sensor by Clark and Lyons in 1962
, generally recognized as the first biosensor, many types of sensors h
ave been developed in which a physical or chemical transducer is provi
ded with a layer containing a biological sensing element. The resultin
g device is called a biosensor, aimed to produce an electronic signal
as a function of the concentration of a chemical or biochemical consti
tuent of a liquid, not necessarily of biological origin. Among the man
y proposed concepts, the integration of biologically active materials
with a silicon chip is one of the most intriguing approaches, because
it seems the most comprehensive integration between biology and electr
onics. In this paper the resulting biochips, mainly based on the field
-effect principle as the coupling mechanism between the two domains, w
ill be described and discussed with an outlook on the future.