A biosensor is a device that detects the presence or concentration of specific biomolecules, microorganisms or other biological analytes. Detection takes place in three steps:
- binding of the analyte to a specific recognition element (bioreceptor)
- translation of the biological binding event into a physicochemical signal (transduction)
- processing of the signal into useful information (e.g. concentration)
Many different types of transducers are available, all translating a biological signal into a measurable quantity, which can be optical (e.g. refractive index, light intensity), electrical (e.g. potential, current) or mechanical (mass). Once the signal is transduced, it can be processed (e.g. amplification, filtering) and converted into relevant (bio)chemical information such as concentration.