MOLECULAR ELECTRONICS

Within the context of mimetics, the Nanobionics group has created strategies to study biomolecular affinity and molecular binding kinetics in a chip – termed as a biosensor. The electrochemical biosensor’s interface is highly selective and able to detect any analyte of interest by the combination of a biological receptor component and a physicochemical transducer. Electrochemical biosensors use electrochemical concepts as transducer signal to convert a biological reaction or a binding event into a measurable and quantifiable electronic signal. By immobilizing a biological molecule, such as a marker antibody for a particular disease on the surface of the microelectrodes designed at the molecular level, it is possible to detect, for example, the presence of its antigen in a blood sample by means of quantum capacitive methods: any electrical signal different from the reference signal can be identified and quantified, allowing, for example, the early diagnosis of different diseases. Indeed  the quantification of biological or biochemical processes  is  of  utmost  importance  for  medical,  biological  and  biotechnological  applications.

The  general  performance  of  electrochemical  biosensor  devices  is  often  a  combination  of  the  surface architectures  (that  connects  the  sensing  element  to  the  biological  sample  at  the  nanometer  scale) with  the transduction signal used. Electrochemical biosensors based on potenciometric principles monitor changes on the electrode potential caused by any biological event occurring on the biosensor’s interface that modifies the equilibrium of the redox reaction. Amperometric biosensors are relatively sensitive and operate based on the measurement of the direct current (DC) current or current density associated with an  electrochemistry  reaction  occurring  in  the  biosensor’s  surface usually due to the  application  of  an electrochemical  potential difference  between  the  current  collector  and  the  counter  electrode. Impedimetric biosensors are based on the electrochemical impedance  measurement  which  is  indeed related  to  the  opposition  that  an  electronic  circuit  presents to a current when a small perturbative oscillatory voltage is applied on the interface (electrical impedance).

Possible types of transducers in a biosensor and the four different types for those devices based on electrochemical transducer concepts
Possible types of transducers in a biosensor and the four different types for those devices based on  electrochemical transducer concepts.