Label-free antibody-antigen binding detection by optical sensor array based on surface-synthesized gold nanoparticles

Area of Science:

• Nanotechnology
• Biochemistry
• Analytical Chemistry

Background:

• Development of sensitive and label-free biosensing platforms is crucial for rapid diagnostics.
• Gold nanoparticles (AuNPs) offer unique optical properties for biosensing applications.
• Existing methods often require sample labeling, increasing complexity and cost.

Purpose of the Study:

• To fabricate and characterize a novel biosensor array utilizing in situ grown gold nanoparticles.
• To demonstrate the label-free detection of antibody-antigen interactions using light-scattering properties.
• To determine the kinetic parameters and sensitivity of the developed biosensor for whole blood samples.

Main Methods:

• In situ growth of gold nanoparticles on a glass substrate from printed seed particles.
• Functionalization of the nanoparticle surface with model proteins (fibrinogen, bovine serum albumin).
• Real-time monitoring of refractive index changes via light-scattering measurements upon antibody-antigen binding.
• Kinetic analysis to derive association rate constants.

Main Results:

• The fabricated gold nanoparticle surfaces exhibited sensitivity to local refractive index changes.
• Label-free detection of specific antibody-antigen binding was successfully demonstrated using scattered radiation.
• Real-time kinetic data allowed for the derivation of association rate constants.
• A minimum antibody concentration detection sensitivity of 100 nM was achieved.

Conclusions:

• The developed gold nanoparticle biosensor array offers a sensitive and label-free approach for detecting biomolecular interactions.
• The in situ nanoparticle growth method provides a robust platform for biosensor fabrication.
• This technology has potential applications in diagnostics and real-time biomolecular analysis using whole blood.