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A novel dry method for surface modification of SU-8 for immobilization of biomolecules in Bio-MEMS

Biosens Bioelectron. 2007 May 15;22(11):2429-35. doi: 10.1016/j.bios.2006.08.045. Epub 2006 Oct 10.

Abstract

SU-8 has been primarily used for structural elements and microfludics components in MEMS. Microsystems for biological applications require immobilization of biomolecules on the MEMS structures. In order to functionalize SU-8 for such purposes, the surface needs to be modified. In this paper, we report a novel dry method of surface modification of SU-8 which is compatible with standard microfabrication techniques. The surface obtained by spin coating SU-8 (2002) on silicon wafer was modified by grafting amine groups using pyrolytic dissociation of ammonia in a hotwire CVD setup. To demonstrate the presence of amine groups on modified SU-8 surface, the surface characteristic after modification was assessed using Fourier transform infrared spectroscopy. The change in SU-8 surface morphology before and after surface modification was investigated using atomic force microscopy. To show the utility of this process for application in Bio-MEMS, SU-8 microcantilevers were fabricated and subjected to the same surface modification protocol. Following this, the cantilevers were incubated first in a suspension of human immunoglobulin (HIgG) and then in FITC tagged goat anti-human IgG in order to demonstrate the utility of the surface modification performed. The efficacy of the process was assessed by observing the cantilevers under a fluorescence microscope.

MeSH terms

  • Acrylic Resins / chemistry*
  • Adsorption
  • Biopolymers / chemistry*
  • Biosensing Techniques / methods*
  • Immunoassay / methods*
  • Immunoglobulin G / analysis*
  • Immunoglobulin G / immunology
  • Materials Testing
  • Surface Properties

Substances

  • Acrylic Resins
  • Biopolymers
  • Immunoglobulin G