Background: Integrating (bio)molecules into electronic junctions is a challenging research area, which combines nano-science and -technology, biophysics, and bio-electrochemistry. Apart from the principal aim of my research, which is to learn about electron transport through (bio)molecules, a potentially practical future goal may be the use of proteins as building blocks to develop multi-functional electronic devices for applications, such as biomedical ones, biofuel cells, and biosensing devices. As part of the effort to achieve our goal, we want to understand how the mechanism of electron transfer (ET) in the natural liquid surroundings of a protein compares to that of electron transport (ETp) in the solid-state, i.e., in dry proteins (dry in the sense that they keep only the structural water).
The last two decades have seen a great rise in research focused on the electron transport properties of various biological molecules. Behind this interest are two main goals: A) to deepen our understanding of natural processes involving charge transport, and B) to explore the potential of biomolecules to be incorporated into bio-electronic devices. Among other classes of biomolecules, proteins enjoy particular attention due to their natural diversity in structure and function, including those related to charge transport. Natural redox proteins are known to facilitate electron transport over long distances (nanometer scale), making cellular processes like photosynthesis and respiration possible. Although much effort has been put into investigating which mechanisms allow proteins to support electron flow – that is, in terms of efficiency comparable to that of organic semiconductors – many aspects remain unresolved.
Some on-going projects in Protein Electronics theme:
Project 1: Charge transport studies through Copper protein junctions
Studying charge transport through copper-containing protein junctions is important because it connects biological electron-transfer principles with molecular-scale electronic transport. Copper proteins are particularly interesting because nature has evolved specialized copper-binding sites that facilitate efficient and selective electron transfer in biological systems. Investigating proteins such as Azurin, CuA domain of Cytochrome c oxidase, laccase, etc., between gold electrodes, can reveal how the copper center, its surrounding protein environment, and the interfaces between protein layers influence electron transport.
Project 2: Tuning Electron Transport in Protein Bilayer Junctions
The study primarily investigates how an additional protein layer influences charge transport beyond the behaviour observed in a single self-assembled layer. The additional protein layer can modify the transport distance, interfacial coupling, and electronic interactions between the electrodes. By systematically modulating charge transport across protein bilayer junctions, we aim to elucidate changes in the effective energy barrier, interfacial electronic coupling, and underlying electron-transport mechanisms.