自组装膜上细胞色素c的电化学石英晶体微天平实时表征和定量检测

Real-time Characterization and Quantitative Detection of Cytochrome c Based on SAMs with Electrochemical Quartz Crystal Microbalance

采用电化学石英晶体微天平(EQCM)实时表征和定量检测细胞色素c(Cytc).在压电石英晶振表面上自组装巯基十一酸(MUA)单层膜,以盐酸1-乙基-3-(3-二甲基氨基丙基)碳二亚胺(EDC)和N-羟基琥珀酰亚胺(NHS)活化羧基,将Cytc共价固化到电极表面.EQCM实时监测了MUA的自组装和Cytc的固化过程,测定了二者在电极表面的覆盖度和Cytc的固化量.结果表明,Cytc在0.03～3.00μmol/L浓度范围内呈线性变化,检测限可达到1.19×10-9mol/L.

Electrochemical quartz crystal microbalance(EQCM), which is capable of sensitive measurement for mass and electrochemical signals, was employed to study cytochrome c. Self-assembled monolays(SAMs) with carboxy groups were first coated on the gold electrode of a quartz crystal resonator by adsorption of ω-mercaptoundecanoic acid(MUA), cytochrome c was then covalently attached to the surface via N-ethyl-N′-\ carbodiimide hydrochloride(EDC) and N-hydroxysuccinimide(NHS). The processes for self-assembly of MUA and immobilization of cytochrome c were both real-time characterized. And the surface coverage densities of MUA and cytochrome c were estimated to be 3.73×10^(-9) and 7.31×10^(-11) mol/cm^2, respectively. The amount of cytochrome c was found to be proportional to the frequency changes between 0.03 μmol/L and 3.0 μmol/L, with a regression equation Δf(Hz)=50.19 c(Cyt C)+67.07(r^2=0.998), and the limit of detection of 1.19×10^(-9) mol/L was also attained.