(Invited) Engineering of Enzymatic Bioelectrochemical Interface for In Vivo Analysis

Abstract

Bioelectrocatalysts have enabled a rapid development of sensing methods and devices for in vivo quantification of chemical species, which is crucial for understanding the molecular basis of life. However, these sophisticated functional units face a set of challenges when operated in vivo . One inevitable issue is the kinetic barrier for heterogeneous electron transfer at the electrode-enzyme interface, especially when direct electron transfer (DET) is preferred as toxic and unstable mediators are not suitable for in vivo applications. Different strategies have been explored to improve DET efficiency, and lately, a new method for regulating the molecular orientation of laccase on single-walled carbon nanotubes was developed based on the principle of surface wetting. Electrochemical and vibrational spectroscopic investigation drew a mechanistic picture of how enzymes behave in the presence of wetting reagents (such as ethanol), offering a new guidance for the design of bioelectrochemical interfaces. Another issue associated with in vivo biosensing rises from interference of intrinsically existing substrates (other than the analytes) for enzymes, e.g., oxygen and NAD + that function as electron acceptors for commonly employed oxidases and dehydrogenases. In our recent studies, we have explored a new enzyme candidate, ferredoxin-dependent glutamate synthase (Fd-GltS), as a bioelectrocatalyst. Containing multiple redox centers, Fd-GltS can be fined tuned with various mediators to enable either bioelectrosynthsis of glutamate or bioelectrochemical oxidation of glutamate. By this means, we can construct a new bioelectrochemical interface devoid of oxygen and cofactor interference, thus providing a new option for the development of biosensing platform for glutamate-mediated neurotransmission.

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Identifiers

DOI

10.1149/ma2019-01/38/1903

Journal

ECS Meeting Abstracts

Year

2019