Table 2: Biological recognition elements and transducers usually used in the development of biosensors.

Biological recognition elementsTransducers

(i) Cells
(ii) Membranes
(iii) Nucleic acids
(iv) Protein:
 (a) Antibodies
 (b) Enzymes
 (c) Membrane   receptors
 (d) Nuclear    receptors
 (e) Peptides
(i) Optical
 (a) Fluorescence (BRET, FRET,  fluorescence anisotropy )
 (b) Colorimetry
 (c) Surface plasmon resonance (SPR)
 (d) Reflectometric interference  spectroscopy (RfIS)
(ii) Electrochemical
 (a) Amperometric
 (b) Conductimetry
 (c) Potentiometry
(iii) Piezoelectric
 (a) Quartz crystal microbalance (QCM)
(iv) Thermal
 (a) Differential scanning  microcalorimetry (DSC)
 (b) Isothermal microcalorimetry (ITC).