Immobilization of myoglobin on Au nanoparticle-decorated carbon nanotube/polytyramine composite as a mediator-free H2O2 and nitrite biosensor

A. T.Ezhil Vilian, Vediyappan Veeramani, Shen Ming Chen, Rajesh Madhu, Cheol Hwan Kwak, Yun Suk Huh, Young Kyu Han

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    Abstract

    A novel composite film was designed for use as a highly selective mediator-free amperometric biosensor, and a method was created for accomplishing direct electrochemistry of myoglobin on a multi-walled carbon nanotube and tyramine-modified composite decorated with Au nanoparticles on a glassy carbon electrode. The ultraviolet-visible and electrochemical impedance spectroscopy results showed that myoglobin retained its native conformation in the interaction with Au-PTy-f-MWCNT. The surface coverage of Mb-heme-Fe (II)/(III) immobilized on Au-PTy-f-MWCNT and the heterogeneous electron-transfer rate constant were 2.12 × 10 â '9 mol cm â '2 and 4.86 s â '1, respectively, indicating a higher loading capacity of the nanocomposite for direct electron transfer of Mb onto the electrode surface. The proposed Mb/Au-PTy-f-MWCNT biofilm exhibited excellent electrocatalytic behavior toward the reduction of H2O2 and the oxidation of nitrite with linear ranges of 2 to 5000 Î 1/4M and 1 to 8000 Î 1/4M and lower detection limits of 0.01 Î 1/4M and 0.002 Î 1/4M, respectively. An apparent Michaelis-Menten constant of 0.12 mM indicated that the Mb immobilized on the Au-PTy-f-MWCNT film retained its native activity. This biosensor can be successfully applied to detect H2O2 and nitrite in disinfectant cream, eye drops, pickle juice, and milk samples.

    Original languageBritish English
    Article number18390
    JournalScientific Reports
    Volume5
    DOIs
    StatePublished - 17 Dec 2015

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