Gold-nanoparticle enhanced in-situ immunosensor based on fiber-optical Fabry-Perot interferometry

This paper proposes a novel method employing gold-nanoparticle to enhance optic fiber Fabry-Perot (F-P) interferometry signal and applied to immunoassay of rabbit IgG and anti-rabbit IgG. In the sensor preparation, cysteine molecules were immobilized on the sensor surface to allow attachment of gold-nanoparticles. Experiment results show that the spectrum shift can be improved by one order of magnitude as employing 40 nm nanoparticles compared to the traditional detection ways by Fabry-Perot interferometry. The minimum detectable concentration of 10⁷ particles/μl was reached. Furthermore, the fiber sensor system was applied to the detection of immuno-reaction of rabbit-IgG and anti-rabbit IgG The whole immuno sensing process including antibody binding and surface regeneration by elution took about 9 minutes, 3 times faster than the traditional way by micro dialysis.