Feng Chuan Liang, Zhang Zhihong, Förch Renate, Knoll Wolfgang, Vancso G Julius, Schönherr Holger
Department of Materials Science and Technology of Polymers, MESA Institute for Nanotechnology and Faculty of Science and Technology, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands.
Biomacromolecules. 2005 Nov-Dec;6(6):3243-51. doi: 10.1021/bm050247u.
Spin-coated thin films of poly(N-hydroxysuccinimidyl methacrylate) (PNHSMA) on oxidized silicon and gold surfaces were investigated as reactive layers for obtaining platforms for biomolecule immobilization with high molecular loading. The surface reactivity of PNHSMA films in coupling reactions with various primary amines, including amine-terminated poly(ethylene glycol) (PEG-NH2) and fluoresceinamine, was determined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and ellipsometry measurements, respectively. The rate constants of PEG-NH2 attachment on the PNHSMA films were found to be significantly increased compared to the coupling on self-assembled monolayers (SAMs) of 11,11'-dithiobis(N-hydroxysuccinimidylundecanoate) (NHS-C10) on gold under the same conditions. More significantly, the PEG loading observed was about 3 times higher for the polymer thin films. These data indicate that the coupling reactions are not limited to the very surface of the polymer films, but proceed into the near-surface regions of the films. PNHSMA films were shown to be stable in contact with aqueous buffer; the swelling analysis, as performed by atomic force microscopy (AFM), indicated a film thickness independent swelling of approximately 2 nm. An increased loading was also observed by surface plasmon resonance for the covalent immobilization of amino-functionalized probe DNA. Hybridization of fluorescently labeled target DNA was successfully detected by fluorescence microscopy and surface plasmon resonance enhanced fluorescence spectroscopy (SPFS), thereby demonstrating that thin films of PNHSMA comprise an attractive and simple platform for the immobilization of biomolecules with high densities.
研究了聚（甲基丙烯酸N-羟基琥珀酰亚胺酯）（PNHSMA）在氧化硅和金表面旋涂的薄膜作为反应层，用于获得具有高分子负载量的生物分子固定平台。分别通过傅里叶变换红外（FTIR）光谱、X射线光电子能谱（XPS）、荧光显微镜和椭偏测量法，测定了PNHSMA薄膜在与各种伯胺（包括胺基封端的聚乙二醇（PEG-NH2）和荧光素胺）偶联反应中的表面反应性。发现在相同条件下，与金表面11,11'-二硫代双（N-羟基琥珀酰亚胺基十一烷酸酯）（NHS-C10）的自组装单分子层（SAMs）偶联相比，PEG-NH2在PNHSMA薄膜上的附着速率常数显著增加。更显著的是，聚合物薄膜的PEG负载量约高3倍。这些数据表明偶联反应不限于聚合物薄膜的表面，而是进入薄膜的近表面区域。结果表明PNHSMA薄膜与水性缓冲液接触时是稳定的；通过原子力显微镜（AFM）进行的溶胀分析表明薄膜厚度有大约2nm的与厚度无关的溶胀。通过表面等离子体共振也观察到氨基功能化探针DNA共价固定的负载量增加。通过荧光显微镜和表面等离子体共振增强荧光光谱（SPFS）成功检测到荧光标记的靶DNA的杂交，从而证明PNHSMA薄膜是用于高密度固定生物分子的有吸引力且简单的平台。
