DNA immobilization on polymer-modified Si surface by controlling pH

DEMİREL G., Çaykara T.

Applied Surface Science, vol.255, no.13-14, pp.6571-6576, 2009 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 255 Issue: 13-14
  • Publication Date: 2009
  • Doi Number: 10.1016/j.apsusc.2009.02.042
  • Journal Name: Applied Surface Science
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.6571-6576
  • Keywords: Biosensor, DNA immobilization, pH dependence, Polymer-modified surface, Self-assembly
  • Ankara Haci Bayram Veli University Affiliated: No


A novel approach based on polymer-modified Si surface as DNA sensor platforms is presented. The polymer-modified Si surface was prepared by using 3-(methacryloxypropyl)trimethoxysilane [γ-MPS] and poly(acrylamide) [PAAm]. Firstly, a layer of γ-MPS was formed on the hydroxylated silicon surface as a monolayer and then modified with different molecular weight of PAAm to form polymer-modified surface. The polymer-modified Si surface was used for dsDNA immobilization. All steps about formation of layer structure were characterized by ellipsometry, atomic force microscopy (AFM), attenuated total reflectance Fourier transformed infrared (ATR-FTIR), and contact angle (CA) measurements. We found that in this case the amount of dsDNA immobilized onto the surface was dictated by the electrostatic interaction between the substrate surface and the DNA. Our results thus demonstrated that DNA molecules could be immobilized differently onto the polymer-modified support surface via electrostatic interactions. © 2009 Elsevier B.V. All rights reserved.