Combination of laccase and catalase in construction of H _2O _2-O _2 based biocathode for applications in glucose biofuel cells

摘要

In this study, we propose a new strategy to boost the power density of glucose biofuel cells (GBFCs) biocathodes. By combining laccase with catalase enzymes electrophoretically deposited by means of AC electric fields on multiple walled carbon nanotubes modified platinum black and, then stabilized by an outer layer of polypyrrole in the construction of GC/MWCNTs/Ptb/LAc-CAt/PPy biocathode, we can take advantage of the H _2O _2 present in the solution or body tissue to increase the level of the dissolved O _2. The results from cyclic voltammetry, amperometry and electrochemical impedance spectroscopy demonstrate that the deposited enzymes laccase and catalase by means of AC-EPD did not inhibit each other and carry out ~90% of the catalytic reduction process of O _2-H _2O _2. The power density of the non-compartmentalized GBFC constructed from GC/MWCNTs/Ptb/LAc-CAt/PPy biocathode and GC/MWCNTs/GOx/PPy bioanode in phosphate buffer containing 10mM glucose and equal amounts of dissolved O _2 and H _2O _2 (0.3mM) is almost doubled because of the presence of catalase enzyme in the constructed biocathode. The latter might be of great interest for in vivo studies of GBFCs where the concentration of dissolved O _2 in the body tissues or biological fluids is very low compared to in vitro conditions (buffers under air).