Dependence of the signal amplification potential of colloidal gold nanoparticles on resonance wavelength in surface plasmon resonance-based detection.

We demonstrate the resonance wavelength-dependent signal of colloidal gold nanoparticles adsorbed to a planar gold surface in surface plasmon resonance (SPR)-based detection. Experimental measurements of the SPR signal as a function of particle surface coverage are presented for three different resonance wavelengths. The SPR signal due to the colloidal gold nanoparticles varies across the resonance wavelengths of 650 nm, 770 nm, and 920 nm. The experimental SPR curves show good agreement with the results of a Lorentz absorbance model at the lower particle surface coverages investigated. The results demonstrate an almost twofold signal difference for a subset of the experimental conditions explored.