Optical Label-Free Nanoplasmonic Biosensing Using a Vertical-Cavity Surface-Emitting Laser and Charge-Coupled Device

We present a compact platform for biochemosensing based on the combination of a vertical-cavity surface- emitting laser (VCSEL) light source, microelectrome- chanical systems (MEMS)-based microoptics, a specially designed nanoplasmonic sensing chip, and charge- coupled device (CCD) detector. The platform does not require any spectral analyzer for signal evaluation, show- ing good promise for facile integration, neither does it use any microscope setup for the signal collection or imaging. The analytical capabilities of the developed biochemosens- ing platform are demonstrated by evaluation of the protein-substrate (biotinylated bovine serum albumin- gold) and the protein-protein (biotin-NeutrAvidin) bind- ing kinetics, which is further compared to detection based on conventional optical extinction spectroscopy. The instrument is able to detect low femtomoles of adsorbed proteins with the limit of detection comparable to the state-of-the-art research and commercial optical label-free biochemosensors.