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 language | English |
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Article number | 18390 |
Journal | Scientific Reports |
Volume | 5 |
DOIs | |
State | Published - 17 Dec 2015 |
Bibliographical note
Funding Information:The authors acknowledge the financial support from the Ministry of Science and Technology, Taiwan (ROC) and National Research Foundation of Korea (NRF) grant by the Korea government Ministry of Education, Science and Technology (MEST) (2010-C1AAA001-0029018) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2014R1A5A1009799).