Quantitative FT-IRRAS spectroscopic studies of the interaction of avidin with biotin on functionalized quartz surfaces

J Phys Chem B. 2005 Sep 8;109(35):16866-72. doi: 10.1021/jp0535240.

Abstract

The interaction of avidin with biotin was studied on functionalized quartz surfaces terminated with 3-aminopropyltrimethoxysilane (3-APTMS), 2,2'-(ethylenedioxy)bis(ethylenediamine) (DADOO), and fourth-generation amine-terminated polyamidoamine (G4-NH2 PAMAM) dendrimers with the use of Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS). In particular, the molecular recognition ability of these surfaces was quantified through FT-IRRAS in combination with the use of an alkyne dicobalt hexacarbonyl probe coupled with avidin. The degree of nonspecific adsorption of avidin was determined by exposure of the amine-terminated and/or biotinylated surfaces to solutions of biotin-saturated avidin. The results indicate that the biotinylated 3-APTMS layer exhibits a very low specific binding capacity for avidin (on the order of 0.15 pmol of avidin/cm2) and substantial nonspecific adsorption. Both the binding capacity and the specificity were greatly improved when the 3-APTMS layer on quartz was modified through serial chemisorption of glutaraldehyde (GA), DADOO, and/or G4-NH2 PAMAM dendrimer layers. Among these layers, the biotinylated G4-NH2 PAMAM dendrimer layer exhibited the highest capacity for avidin binding (2.02 pmol of avidin/cm2) with a specificity of approximately 90%. This effect can be attributed to the efficient packing/ordering of the binding dendrimer layer, leading to a more dense and better organized layer of biotin headgroups on the subsequent biotinylated surface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Avidin / chemistry*
  • Biotin / chemistry*
  • Protein Binding
  • Quartz / chemistry*
  • Spectroscopy, Fourier Transform Infrared / methods*
  • Spectrum Analysis / methods*

Substances

  • Avidin
  • Quartz
  • Biotin