Yin Tanji, Wei Wanzhi, Yang Liu, Liu Kai, Gao Xiaohua
State Key Laboratory of Chemical, Biological Sensing Technologies and Chemometrics, Hunan University, Changsha, 410082, PR China.
J Biochem Biophys Methods. 2007 Jun 10;70(4):587-93. doi: 10.1016/j.jbbm.2007.01.009. Epub 2007 Jan 27.
A novel method for real-time investigating the binding interaction between human serum albumin (HSA) and salicylic acid with capacitive sensing technique was successfully proposed. HSA was immobilized on the surface of a gold electrode modified with an insulating poly (o-phenylenediamine) (o-PD) film and colloid Au nanoparticles layers. The bioactivity of HSA was remained and major binding sites were available because of the excellent biocompatibility of gold nanoparticles. The capacitance and interfacial electron resistance of the sensor were altered, owing to the binding of HSA to salicylic acid. The time courses of the capacitance change were acquired with capacitive sensing technique during the binding process. Based on the capacitance response curves with time, the response model for the binding was derived in theory and the corresponding regression parameters were determined by fitting the real-time experimental data to the model. The binding and the dissociation rate constants (k(1) and k(-1)) were estimated to be 54.8 (mol l(-1))(-1) s(-1) and 2.9 x 10(-3) s(-1), respectively. And the binding equilibrium constant (K(a)) was calculated to be 1.89 x 10(4) (mol l(-1))(-1).
成功提出了一种利用电容传感技术实时研究人血清白蛋白（HSA）与水杨酸之间结合相互作用的新方法。HSA固定在修饰有绝缘聚邻苯二胺（o-PD）膜和胶体金纳米颗粒层的金电极表面。由于金纳米颗粒具有优异的生物相容性，HSA的生物活性得以保留，主要结合位点也可利用。由于HSA与水杨酸的结合，传感器的电容和界面电子电阻发生了变化。在结合过程中，利用电容传感技术获取电容变化的时间历程。基于电容随时间的响应曲线，从理论上推导了结合的响应模型，并通过将实时实验数据拟合到该模型来确定相应的回归参数。结合和解离速率常数（k(1)和k(-1)）估计分别为54.8（mol l(-1)）(-1) s(-1)和2.9×10(-3) s(-1)。结合平衡常数（K(a)）计算为1.89×10(4)（mol l(-1)）(-1)。
