聚甲基丙烯酸甲酯-牛血清白蛋白核壳纳米粒子在金表面的吸附过程及在传感器中的应用

利用铜离子引发体系, 制备出核层为聚甲基丙烯酸甲酯(PMMA)壳层为牛血清白蛋白(BSA)的PMMA-BSA核壳纳米粒子. 通过透射电子显微镜(TEM)表征, 直接观察到PMMA-BSA纳米粒子的核壳结构.结合X射线光电子能谱(XPS)测试, 分析PMMA-BSA纳米粒子的表面成分, 证明PMMA-BSA纳米粒子的壳层是BSA. 利用带耗散的石英晶体微天平(QCM-D)研究了PMMA-BSA纳米粒子在金片表面的吸附行为. 频率的迅速下降, 耗散因子的快速上升, 说明PMMA-BSA粒子快速地吸附到金片表面. 利用磷酸盐缓冲液反复冲洗时, 频率和耗散没有变化, 表明PMMA-BSA 纳米粒子在金片上吸附较牢固. 以金电极为基底电极, 吸附PMMA-BSA纳米粒子后, 利用戊二醛修饰粒子壳层, 再通过氨基与醛基的反应来固定葡萄糖氧化酶, 制备出电流型葡萄糖传感器. 电化学测试表明该传感器对葡萄糖具有良好的电流响应, 在0.3 V的工作电位下, 响应电流与葡萄糖浓度在0.20-5.85 mmol·L^-1范围内呈现出较好的线性关系, 相关系数为0.989. 传感器的灵敏度高达28.6 μA·L·mmol^-1·cm^-2, 响应时间仅为11 s. 传感器还具有良好的稳定性, 在25℃下储存30 d, 响应电流仅下降了16%.

Adsorption of Core-Shell Poly(Methyl Methacrylate)-Bovine Serum Albumin Nanoparticles on Gold Surface and Its Sensor Application

Core-shell poly(methyl methacrylate)-bovine serum albumin (PMMA-BSA) nanoparticles with PMMA cores and BSA shells were prepared via a copper ion-mediated initiation system. The core-shell structure of the nanoparticles was characterized by transmission electron microscopy (TEM) and the surface compositions of the nanoparticles were tested by X-ray photoelectron spectroscopy (XPS), which further demonstrated that the particles have a BSA protein shell. The adsorption of these PMMA-BSA particles onto gold surfaces was studied by quartz crystal microbalance with dissipation (QCM-D). The significantly change of frequency shift and dissipation factor indicated that PMMA-BSA particles are adsorbed on the gold surface. The repeated buffer washing had nearly no effect on either frequency shift or dissipation factor, revealing that the adsorption is fairly strong. An amperometric glucose biosensor was constructed by immobilizing glucose oxidase on PMMA-BSA particles modified with glutaraldehyde, using a gold electrode as a substrate on which to adsorb the PMMA-BSA particles. Electrochemical measurements show this biosensor exhibited a good current response to glucose. Working at 0.3 V, the biosensor had a short response time of 11 s, a sensitivity of 28.6 μA·L^-1·mmol^-1·cm^-2 and a linear range from 0.2 to 5.85 mmol·L^-1 with a correlation coefficient of 0.989. After storage at 25℃ for one month, the sensor response current decreased by only 16%, thus showing good thermal stability.