Printable and organic bioelectronic is a highly interdisciplinary research field that aims at the development of key-technologies to investigate biointerfaces as well as to face novel challenges in life-science and medicine [1]. It currently encompasses, besides biosensors, many other different applications, including neural interfaces, tissue engineering and drug delivery. It is a powerful tool that exploits the direct interfacing of a field-effect transistor (FET) with functioning or even living bio-systems. These systems can be used to investigate fundamental aspects of bio-chemical interactions and exploit this knowledge to realize ultra-sensitive biological and chemical sensor.
These systems can be used to investigate fundamental aspects of bio-chemical interactions and exploit this knowledge to realize ultra-sensitive biological and chemical sensors. Bioelectronic FET micro-devices are based on solution processed organic semiconductors but also on printable metal oxides, carbon nanotubes as well as graphenes. Novel devices structures that integrate a layer of functional biological recognition elements that is directly coupled with an electronic interface, have been lately proposed. The study of such interfaces allowed to get insights into the understanding of conformational changes occurring in the bio-systems upon interaction with external stimuli and to obtain label-free, ultra-sensitive and selective biosensing [2,3,4].
In particular, the ultra-sensitive, quantitative measurement of the weak interactions associated with neutral enantiomers differentially binding to odorant binding proteins immobilized to the gate of an organic bio-electronic transistor [3], will be presented. It will be shown that the transduction is remarkably sensitive as the transistor output current is governed by the small capacitance of the protein layer undergoing minute changes as the ligand-protein complex is formed. Accurate determination of the free-energy balances and of the capacitance changes associated with the binding process allows derivation of the free-energy components as well as of the occurrence of conformational events associated with ligand binding. Capacitance modulated transistors open a new pathway for the study of ultra-weak molecular interactions in surface bound protein-ligand complexes through an approach that combines bio-chemical and electronic thermodynamic parameters.
[1] J. Rivnay et al. Chem. Of. Mat. 26, 679, 2014 [2] L. Torsi et al. Chem. Soc. Rev. 42, 8612, 2013 [3] Y. Mulla et al. Nat. Comm. 2015 10.1038/ncomms7010 [4] G. Palazzo et. al. Adv. Mat. 2014 DOI: 10.1002/adma.201403541