Developing efficient enzyme based, clean bioreactors for the green production of drug metabolites and precious fine chemicals with high stereo-specificity possesses an enormous potential in improving human health by offering affordable medications, and also in protecting our environment by green syntheses. To develop efficient bioreactors with high catalytic efficiency in a minimal reactor volume, elegant tailoring of remarkable enzyme catalysts with unique nanomaterials has been an attractive area of research recently. In addition, the sensing application of enzyme biosensors can be tremendously improved on the sensitivity aspect by incorporating nanomaterials. In particular, the role of magnetic particles (both nano- and micro-particles) in the development of modern ultra-sensitive electrochemical and optical biosensors is immense, and more research avenues both on the fundamental and applied aspects remain to be explored.We present here the direct electron-transfer and electrocatalytic kinetics of covalently attached myoglobin (MB) films on magnetic nanoparticles (MB-MNPcovalent), and compare the properties with the corresponding physisorbed films (MB/MNPadsorbed) and individual components (only MB or only MNP) immobilized on graphite electrodes. The observed heterogeneous electron-transfer rate constants (ks, s-1) were in the following order: MB-MNPcovalent >> MB/MNPadsorbed > only MB > only MNP. We observed the following order of catalytic reduction current density: MB-MNPcovalent > MB/MNPadsorbed > only MNP > only MB, in agreement with the electron-transfer (ET) rates of MB-MNPcovalent and MB/MNPadsorbed films. The role of MNP in favorably altering the direct ET and electrocatalytic properties of both covalently bound MB and physisorbed MB molecules will be detailed. In addition, the occurrence of highly enhanced electron-hopping mechanism in these films will be discussed.The novel findings of this study are suggested to possess an enormous importance in the development of novel efficient biosensors, nanochip-devices, bioreactors, and in the fundamental mechanistic studies of other enzyme films. The financial support by Oklahoma State University is greatly acknowledged.

Enhanced electrochemical features of a heme protein bound to magnetic nanoparticles

247th National Meeting (2014)

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