Nanoparticle-based protein detection by optical shift of a resonant microcavity

We demonstrated a biosensing approach which, for the first time, combines the high sensitivity of whispering gallery modes (WGMs) with a metallic nanoparticle-based assay. We provided a computational model based on generalized Mie theory to explain the higher sensitivity of protein detection. We quantitatively analyzed the binding of a model protein (i.e., Bovine Serum Albumin) to gold nanoparticles from high-Q WGM resonance frequency shifts, and fit the results to an adsorption isotherm, which agrees with the theoretical predictions of a two-component adsorption model. Read more (COVER PAPER): http://apl.aip.org/resource/1/applab/v99/i7/p073701_s1