A method of binding kinetics of a ligand to micropatterned proteins on a microfluidic chip

Biosens Bioelectron. 2007 Jan 15;22(6):891-8. doi: 10.1016/j.bios.2006.03.020. Epub 2006 May 6.

Abstract

A combination of microfluidic protein patterning and quantitative microfluidic handling has been used to analyze the binding kinetics of protein-ligand interactions on the nanoliter scale. The microfluidic handling method employing hydrophobic valving and pneumatic control allowed us to control nanoliter volumes of ligand or protein on a microfluidic chip. A hydrophobic and inert fluorocarbon thin film was patterned on a silicon nitride substrate to prevent non-specific binding on the background. Selectively patterned protein patterns of various sizes were used for quantitative analysis of the kinetic parameters of immobilized proteins on the circular patterns. As a model system, a streptavidin-patterned array of the same-sized pattern, i.e. 150 microm diameter, was used to capture FITC-BSA-biotin present in solution. The fluorescence intensity was well matched with the Langmuir isotherm model results, showing a dissociation constant of 2.43x10(-8)M. Similar streptavidin arrays with different-sized spots, ranging from 50 to 200 microm, showed a consistent dissociation constant of FITC-BSA-biotin with streptavidin pattern. Therefore, the reduction of pattern size of an immobilized protein did not change the dissociation rate of the ligand.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques / instrumentation*
  • Biosensing Techniques / methods
  • Equipment Design
  • Equipment Failure Analysis
  • Immunoassay / instrumentation*
  • Immunoassay / methods
  • Kinetics
  • Microfluidic Analytical Techniques / instrumentation*
  • Microfluidic Analytical Techniques / methods
  • Protein Binding
  • Protein Interaction Mapping / instrumentation*
  • Protein Interaction Mapping / methods
  • Proteins / analysis
  • Proteins / chemistry*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Spectrometry, Fluorescence / instrumentation*
  • Spectrometry, Fluorescence / methods
  • Surface Properties

Substances

  • Proteins