Electrochemical Quartz Crystal Impedance and Fluorescence Quenching Studies on the Binding of Carbon Nanotubes (CNTs)-Adsorbed and Solution Rutin with Hemoglobin

详细信息    查看全文

• 作者：Yuhua Su ; Qingji Xie ; Qin Yang ; Xinman Tu ; Zhijun Cao ; Xue'en Jia ; Zhaohong Su ; Youyu Zhang ; Wenhua Meng ; Shouzhuo Yao
• 刊名：Biotechnology Progress
• 出版年：2007
• 出版时间：April 2007
• 年：2007
• 卷：23
• 期：2
• 页码：473 - 479
• 全文大小：134K
• 年卷期：v.23,no.2(April 2007)
• ISSN：1520-6033

文摘

Electrochemical quartz crystal impedance (QCI) technique was utilized to monitor in situ theadsorption of rutin (RT) onto a carbon nanotubes (CNTs)-modified gold electrode and to studythe binding process of solution hemoglobin (Hb) to RT immobilized on the electrode. Timecourses of the QCI parameters including crystal resonant frequency were simultaneously obtainedduring the RT adsorption and Hb-RT binding. In contrast to the negligible RT adsorption at abare gold electrode, the modification by CNTs notably enhanced the amount of adsorption, andalmost all of the adsorbed RT molecules were found to be electroactive. On the basis of thefrequency response from the binding of adsorbed RT to solution Hb and the diminishedelectroactivity of adsorbed RT after the formation of the electrochemically inactive RT-Hb adduct,the average binding molar ratio of adsorbed RT to Hb was estimated to be 23.9:1, and theassociation constant (K_a) for the binding was estimated to be 2.87 × 10⁶ (frequency) and3.92 × 10⁶ (charge) L mol^-1, respectively. Comparable results were obtained from fluorescencequenching measurements in mixed solutions containing RT of fixed concentration and Hb ofvarying concentrations, demonstrating that the interfacial RT here behaved equivalently in theRT-Hb binding activity compared to that in solution. This work may have presented a new andgeneral protocol involving CNTs to study many other electroactive natural antioxidants or drugsthat are at the interface or in solution, their binding with proteins or other biomolecules, andchanges of their antioxidant activity after the binding.