Rational Design of Enzyme‐Modified Electrodes for Optimized Bioelectrocatalytic Activity

Abstract

This contribution is dedicated to Prof. Lo Gorton on the occasion of his 70 th birthday in recognition of his outstanding contributions to the field of (bio)electrochemistry over several decadesThe immobilization of bilirubin oxidase (BOD) on macroporous gold electrodes for the optimization of bioelectrocatalytic activity is described. A bilirubin oxidase mutant S362C (cys-BOD) engineered with a cysteine residue located on purpose at the enzyme surface close to the T1 active center was used. It allows the attachment in one-step of a self-assembled monolayer of the enzyme to gold through a reaction between the thiol group of the cysteine residue and the metal surface. BOD immobilization of wild type and S362C mutant in macroporous gold electrodes allowed high retention of activity and perfect control of the overall BOD loading due to the fine-tuning of the macroporous structure. The macroporous arrangement together with the use of cys-BOD makes these rationally designed enzyme-modified electrodes very promising candidates for high-performance bioelectrocatalytic devices with improved activity and stability. long-term stability of cys-BODÀ Au is interpreted as the consequence of the covalent bond between the enzyme and the gold structure, thus avoiding enzyme leaching even after several days of incubation.

Multiscale modelling of diffusion and enzymatic reaction in porous electrodes in Direct Electron Transfer mode

“…The actual active surface area depends on the thickness of the porous layers of the electrode. There is a linear correspondence between the active area of the porous electrode and the number of porous half layers, as reported recently (Zhang et al, 2019).…”

Hierarchical Multiporous Nickel for Oxygen Evolution Reaction in Alkaline Media

“…Interestingly, increasing the number of electrodeposited macroporous layers allows increasing the OER performance. One could think that increasing further the thickness of the porous layer might still lead to a further improvement of the catalytic currents, however as we could show recently by modeling and by independent experiments with electroenzymatic reactions, there is an upper limit, above which it doesn't make sense to further increase the thickness of the porous layer due to diffusion limitations –. The size of the macropores might also have an impact on the OER behavior.…”

Wireless In Vivo Biofuel Cell Monitoring

“…To improve the interaction between the enzyme and the gold surface, and thus increase the rate of electrons transfer, we designed and produced a mutant of this enzyme bearing a cysteine residue, well known to strongly attach to gold surfaces [66]. The mutant BOD has then been directly immobilized onto the porous electrode by a coating process previously described [67]. On the contrary, Glucose Oxidase (GOx) is not able to promote direct electron Fig.…”