A biosensor is an element employed for the detection of an analyte by 
combining a biological component with a physico-chemical detector 
component. Biological component can be microorganisms, cell receptors, 
enzymes, antibodies, nucleic acids. The detector works in a 
physico-chemical way like electrochemical, optical, piezoelectrical, 
electrochemical or thermal that transforms the signal resulting from the
 interaction of the analyte with the biological element into another 
signal that can be easily measured and quantified