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 [Article] doi: 10.3866/PKU.WHXB201207191 www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2012, 28 (11), 2721-2728 November Received: May 14, 2012; Revised: July 19, 2012; Published on Web: July 19, 2012. ∗Corresponding authors. HE Chuan-Xin, Email: hcx2002@mail.ustc.edu.cn. LIU Jian-Hong, Email: szujhliu@yahoo.com.cn; Tel: +86-755-26534173. The project was supported by the National Natural Science Foundation of China (21004040) and Natural Science Foundation of Shenzhen University, China (201102). 国家自然科学基金(21004040)和深圳大学校基金(201102)资助项目 C Editorial office of Acta Physico-Chimica Sinica 2721 Acta Phys. -Chim. Sin. 2012 Vol.28 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 °C for one month, the sensor response current decreased by only 16%, thus showing good thermal stability.