Hydrogen peroxide biosensor based on direct electrochemistry of soybean peroxidase immobilized on single-walled carbon nanohorn modified electrode

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• 作者：Lihong Shi ; Xiaoqing Liu ; Wenxin Niu ; Haijuan Li ; Shuang Han ; Jiuan Chen ; Guobao Xu
• 关键词：Single-walled carbon nanohorns ; Soybean peroxidase ; Direct electrochemistry ; Hydrogen peroxide ; Carbon nanotubes
• 刊名：Biosensors and Bioelectronics
• 出版年：2009
• 出版时间：1 January 2009
• 年：2009
• 卷：24
• 期：5
• 页码：1159-1163
• 全文大小：618 K

文摘

Single-walled carbon nanohorns (SWCNHs) were used as a novel and biocompatible matrix for fabricating biosensing devices. The direct immobilization of acid-stable and thermostable soybean peroxidase (SBP) on SWCNH modified electrode surface can realize the direct electrochemistry of enzyme. Cyclic voltammogram of the adsorbed SBP displays a pair of redox peaks with a formal potential of −0.24 V in pH 5 phosphate buffer solution. The formal potential has a linear relationship with pH from 3 to 9 with a slope of −48.7 mV/pH, close to the value of −55.7 mV/pH expected at 18 °C for the reversible transfer of one proton and one electron. Bioactivity of SBP remains good in SWCNH microenvironment, along with effective catalysis of the reduction of H₂O₂. In the absence of a mediator, this H₂O₂ biosensor exhibited a high sensitivity (16.625 μA L/mmol), a linear range from 0.02 to 1.2 mmol L⁻¹, and a detection limit of 5.0 × 10⁻⁷ mmol L⁻¹, as well as acceptable preparation reproducibility and excellent stability.