Long admired for its brilliant colour, colloidal gold is known to be a fascinating material with exceptional spectral properties. It is now well known that this brilliance is due to the localized surface plasmon resonance (LSPR) of gold nanoparticles (AuNPs) [1], [2] and [3]. LSPR is the collective oscillation of electrons at the surface of a nanostructure, which is excited by incident light of a larger wavelength than the size of the nanostructure. The coherent oscillation results in strong light scattering and a unique surface plasmon absorption spectrum. The intensity and peak location of the absorption and scattering spectra are highly dependent on the nanoparticle shape, size, and composition as well as the refractive index of the surrounding medium. By taking into account the relationship between the LSPR signal and its influencing factors, there has been significant interest in developing high-sensitivity chemical and biological sensors based on nanostructured platforms [3], [4], [5], [6] and [7].