The Role of Lipid-Membrane in the Direct Electrochemistry of Human Liver-Microsomal Films

Cell membranes play a crucial role in molecule/ion transport, cell signaling, bioenergetics, interactions between biomolecules, and many other important biological processes. Due to these significant roles of lipid-membranes in life-processes, investigating the ion and charge-transport processes across them in vitro by designing biomimetic membranes has been an active research area. Lipid-membranes have been used widely to construct artificial photosynthetic systems and efficient electro- and photo-catalytic processes. Nevertheless, the potential of exploiting transport processes across lipid-bilayer membranes in developing robust modern biosensors, biocatalytic systems, and energy-conversion devices is challenging.

We provide here new insights on the direct electrochemical kinetics of micron-thick innate human liver-microsomal films containing embedded oxidoreductases and major drug metabolizing monooxygenase enzymes. Additional insights on the effect of electrode-materials in oxygen binding kinetics to the oxidoreductase reduced heme-proteins present within the HLM-film will also be presented. We were able to control the nominal HLM-film thickness by using different electrode-materials, and thus seem to have influenced the arrangement of redox proteins in the HLM-films. Our results suggest that one can directly use liver-microsomal films coated on appropriate electrodes for drug screening and biosensing applications without requiring purified monooxygenases and reductases, reconstituted assay systems, chemical/NADPH electron donors, and electrode modification procedures. Thus the cost and time of developing novel drug screening platform can be greatly minimized.

Acknowledgements. This work was supported by the Oklahoma State University.