A Simple Construction of Electrochemical Liver Microsomal Bioreactor for Rapid
Drug Metabolism and Inhibition Assays
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Abstract
In order to design a green microsomal
bioreactor on suitably identified
carbon electrodes, it is important to understand the direct electrochemical
properties at the interfaces between various carbon electrode materials
and human liver microsomes (HLM). The novelty of this work is on the
investigation of directly adsorbed HLM on different carbon electrodes
with the goal to develop a simple, rapid, and new bioanalytical platform
of HLM useful for drug metabolism and inhibition assays. These novel
biointerfaces are designed in this study by a one step adsorption
of HLM directly onto polished basal plane pyrolytic graphite (BPG),
edge plane pyrolytic graphite (EPG), glassy carbon (GC), or high-purity
graphite (HPG) electrodes. The estimated direct electron transfer
(ET) rate constant of HLM on the smooth GC surface was significantly
greater than that of the other electrodes. On the other hand, the
electroactive surface coverage and stability of microsomal films were
greater on highly surface defective, rough EPG and HPG electrodes
compared to the smooth GC and less defective hydrophobic BPG surfaces.
The presence of significantly higher oxygen functionalities and flatness
of the GC surface is attributed to favoring faster ET rates of the
coated layer of thin HLM film compared to other electrodes. The cytochrome
P450 (CYP)-specific bioactivity of the liver microsomal film on the
catalytically superior, stable HPG surface was confirmed by monitoring
the electrocatalytic conversion of testosterone to 6β-hydroxytestosterone
and its inhibition by the CYP-specific ketoconazole inhibitor. The
identification of optimal HPG and EPG electrodes to design biologically
active interfaces with liver microsomes is suggested to have immense
significance in the design of one-step, green bioreactors for stereoselective
drug metabolite synthesis and drug metabolism and inhibition assays