Time-resolved spectroelectrochemistry on 3D-mesoporous electrodes – 3D-BIOELEC

Our approach is based on transparent mesoporous metal oxide electrodes with optimized conductivity and transparency. These high surface electrode allows for the immobilization of large amount of biomolecules, up to a quantity easily detected by spectroscopy.
Once prepared, these electrodes are functionalized by the redox probes exhibiting convenient spectroscopic features and a redox-linked reactivity, eventually coupled to a catalytic activity.
The modified electrodes are the characterized by various spectroscopic techniques coupled to electrochemistry, such as UV-visible absorption spectroscopy. The time-resolution can thus be determined, allowing quantitative kinetic analysis of redox-linked processes on the immobilized biomolecule.

The new electroanalytical methodology developed is characterized by a time resolution of ca. 1 millisecond. We demonstrated its interest for the quantitative analysis of the catalytic reactivity of an immobilized molecular catalyst. We also studied in details the interactions between the metal oxide surface and (bio)molecules in order to define functionalization processes under mild conditions. Moreover, our methodology was found to be well-adapted to unravel the processes of charge transfer and electron transport within functionalized mesoporous materials.

We develop new research projects based on he knowledge acquired during the 3D-BIOELEC project. We are especially interested by developing photoelectrochemical cells for applications in chemistry or energy, by coupling semi-conductive metal oxides to photosensitizers and molecular catalysts.

The results obtained were published in international high ranking journals (6 articles and 2 manuscript in preparation).

1- Renault C., Andrieux C.P., Tucker R.T., Brett M.J., Balland V.*, Limoges B.* (2012) J. Am. Chem. Soc. 134, 6834-6845
2- Schaming D., Renault C., Tucker R.T., Lau-Truong S., Aubard J., Brett M.J., Balland V.*, Limoges B.* (2012) Langmuir 28, 14065-14072
3- A. Forget, B. Limoges*, V. Balland* (2015), Langmuir 31,1931-1940
4- C. Renault, L. Nicole, C. Sanchez, C. Costentin*, V. Balland*, B. Limoges* (2015), Phys. Chem. Chem. Phys. 17, 10592-10607
5- A. Forget, R.T. Tucker, M.J. Brett, B. Limoges*, V. Balland* (2015), Chem. Commun. 51, 6944-6947
6- C. Renault, V. Balland, B. Limoges, C. Costentin* (2015), J. Phys. Chem. C., 10592-607

The objective of the 3D-BIOELEC project is to achieve a significant breakthrough in bioelectrochemistry with the development of an original submillisecond time-resolved spectroelectrochemical technique. This methodology is expected to be a powerful tool for investigating fundamental kinetics, thermodynamic and mechanistic aspects of immobilized redox proteins and enzymes by cross-correlation between electrochemical and spectroscopic data.
The key point of the project is to take advantage of a new type of optically transparent and highly conductive mesoporous electrodes recently developed. These 3D-electrodes based on doped metal oxide thin films exhibit a well-opened porosity and a high specific area, well-adapted for the immobilization of high amount of redox-active proteins and their rapid redox conversion. Moreover, their high optical transparency is suitable to couple electrochemistry with various spectroscopic techniques such as UV-visible absorption or resonance Raman. The resulting time-resolved spectroelectrochemical methodology will therefore be well-adapted to the characterization of a wide range of immobilized redox-active proteins or enzymes, as well as to the investigation of their structural and functional integrity, to the determination of their surface concentration, to the unambiguously attribution of their redox potentials, and to get better insights in their electron transfer kinetics and mechanisms.
These fundamental advances are expected to greatly impact biotechnological devices as they will allow to rationalize, predict and optimize the functioning of electrochemical biosensors, bioreactors and biofuel cells. In addition, the acquired expertise in highly transparent and porous 3D-electrodes for protein immobilization is expected to provide new opportunities for the development of original bioelectrochemical devices for energy conversion and/or production.