In Situ and Operando Techniques for Investigating Electron Transfer in Biological Systems

Abstract

When bioelectrochemistry meets other analytical techniques for in situ experiments, new possibilities for understanding the nature of charge‐transfer reactions are provided. Despite progress in recent years in analytical instrumentation, a number of key issues remains for bioelectrochemistry, in terms of the mechanistic description of the surface reactions involved in biomolecules’ electron transfer. The main challenges of these techniques are the concomitant detection of electron transfer and molecular alteration as well as the development of suitable bioelectrodes. This review discusses the most recent and emerging in situ and operando electrochemical methods used to study biological systems such as redox proteins, nucleic acids, small biomolecules, cells, and biomembranes, focusing on electrochemical methods coupled with spectroscopic, spectrometric, and microscopic techniques.

Operando Characterization of Organic Mixed Ionic/Electronic Conducting Materials

“…In recent years, “operando” characterization has become a hot topic in various fields. − The term “operando”, from the Latin verb to operate or work, has come to mean in science as “during operation”, and operando characterization refers to a study performed in application relevant environments, conditions, and geometries. Shown in Figure a, these characterization techniques include spectroscopy, scattering, scanning probe techniques, gravimetric techniques, and computational methods.…”

From Enzyme Stability to Enzymatic Bioelectrode Stabilization Processes

“…Should redox enzymes or biosynthetic catalysts be used, novel methodologies must be developed in order to get new insights in the parameters that limit the stability of bioelectrocatalysis. In situ and in operando methods are certainly the most appealing within the objective of understanding and enhancing bioelectrode stability [308,309]. Recent reviews by Reisner et al and by Crespilho et al discussed various methods, and especially coupled methods, currently available to study bioelectrode interfaces [309,310].…”

“…In situ and in operando methods are certainly the most appealing within the objective of understanding and enhancing bioelectrode stability [308,309]. Recent reviews by Reisner et al and by Crespilho et al discussed various methods, and especially coupled methods, currently available to study bioelectrode interfaces [309,310]. Methods allowing mass or layer thickness quantification, i.e., SPR, QCM-D and ellipsometry, coupled to electrochemistry will give access to the relationship between enzyme loading or release and catalytic response [21,116,271,272,311].…”

De Novo Approach to Encapsulating Biocatalysts into Synthetic Matrixes: From Enzymes to Microbial Electrocatalysts

“…For de novo encapsulation of microbial electrocatalyst, the underlying biohybridization mechanism particularly in the self-assembly process is still unclear. In situ spectroscopic approaches including Raman and FTIR spectroscopies − have been developed to probe the electron transfer in bioelectrochemical systems. These spectroscopic methods, combined with advanced imaging techniques, such as confocal microscopy and scanning electrochemical microscopy, may be used to probe the microbe–matrix interaction and understand the biohybridization process.…”