Reactive Thin Polymer Films as Platforms for the Immobilization of Biomolecules

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• 作者：Chuan Liang Feng ; Zhihong Zhang ; Renate F&ouml ; rch ; Wolfgang Knoll ; G. Julius Vancso ; and Holger Sch&ouml ; nherr
• 刊名：Biomacromolecules
• 出版年：2005
• 出版时间：November 2005
• 年：2005
• 卷：6
• 期：6
• 页码：3243 - 3251
• 全文大小：341K
• 年卷期：v.6,no.6(November 2005)
• ISSN：1526-4602

文摘

Spin-coated thin films of poly(N-hydroxysuccinimidyl methacrylate) (PNHSMA) on oxidized silicon andgold surfaces were investigated as reactive layers for obtaining platforms for biomolecule immobilizationwith high molecular loading. The surface reactivity of PNHSMA films in coupling reactions with variousprimary amines, including amine-terminated poly(ethylene glycol) (PEG-NH₂) and fluoresceinamine, wasdetermined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS),fluorescence microscopy, and ellipsometry measurements, respectively. The rate constants of PEG-NH₂attachment on the PNHSMA films were found to be significantly increased compared to the coupling onself-assembled monolayers (SAMs) of 11,11'-dithiobis(N-hydroxysuccinimidylundecanoate) (NHS-C₁₀) ongold under the same conditions. More significantly, the PEG loading observed was about 3 times higher forthe polymer thin films. These data indicate that the coupling reactions are not limited to the very surface ofthe polymer films, but proceed into the near-surface regions of the films. PNHSMA films were shown tobe stable in contact with aqueous buffer; the swelling analysis, as performed by atomic force microscopy(AFM), indicated a film thickness independent swelling of ~2 nm. An increased loading was also observedby surface plasmon resonance for the covalent immobilization of amino-functionalized probe DNA.Hybridization of fluorescently labeled target DNA was successfully detected by fluorescence microscopyand surface plasmon resonance enhanced fluorescence spectroscopy (SPFS), thereby demonstrating thatthin films of PNHSMA comprise an attractive and simple platform for the immobilization of biomoleculeswith high densities.