A hydrogen peroxide biosensor based on Langmuir-Blodgett technique: Direct electron transfer of hemoglobin in octadecylamine layer.
The present paper describes the modification of hemoglobin (Hb)-octadecylamine (ODA) Langmuir-Blodgett (LB) film on a gold electrode surface to develop a novel electrochemical biosensor for the detection of hydrogen peroxide. Atomic force microscopy (AFM) image of Hb-ODA LB film indicated Hb molecules existed in ODA layer in a well-ordered and compact form. The immobilized Hb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of 4.58+/-0.95s(-1) and a formal potential of -185mV (versus Ag/AgCl) in phosphate buffer (1.0mM, pH 5.0) contain 0.1M KCl at a scan rate of 200mVs(-1), characteristic of Hb heme Fe(III)/Fe(II) redox couple. The formal potential of Hb heme Fe(III)/Fe(II) redox couple in ODA film shifted linearly between pH 5 and 8 with a slope of -23.8mVpH(-1), suggesting that proton took part in electrochemical reaction. The ODA could accelerate the electron transfer between Hb and the electrode. This modified electrode showed an electrochemical activity to the reduction of hydrogen peroxide (H(2)O(2)) without the aid of any electron mediator.
Yin
Fan
F
Department of Electrical Engineering, Dong-A University, Busan 604-714, South Korea; Department of Chemistry, Changshu Institute of Technology, Changshu 215500, PR China.
Shin
Hoon-Kyu
HK
Kwon
Young-Soo
YS