Colloid-gold nanoparticle enhanced detection sensitivity of paired surface plasma waves biosensor

Previous work with amplitude-sensitive paired surface plasma waves biosensor (PSPWB) demonstrated that the detection sensitivity of PSPWB is able to experimentally detect 0.001% sucrose-water solution and biomolecular interaction of 10pg/ml mouse IgG interacting with immobilized anti-mouse IgG successfully. Further development of the detection sensitivity of PSPWB has been conducted by using 20nm in diameter colloid gold nanoparticles conjugated with target molecules that can result in a higher mass coverage and a larger resonant angle change of plasmon resonance, thereby its detection sensitivity is further enhanced significantly. Bare gold nanoparticles, which is randomly suspended in solution, is adopted to differentiate biospecific binding induced further signal enhancement Experimentally, the sensitivity at 330fg/ml of Au-nanoparticle conjugated protein A (PA-Au) interacting with mouse IgG which is immobilized on a CM5 sensor chip was detected successfully. By this arrangement, 6-fold signal amplification is demonstrated compared with the same concentration of PA without conjugated gold nanoparticles.