Revealing Lectin-Sugar Interactions with a Single Au@Ag Nanocube.

An individual nanoparticle-based plasmonic nanotechnology was used for real-time monitoring of lectin-sugar interactions, which could be designed as novel plasmonic nanobiosensors for the detection of trace concanavalin A (ConA) with high sensitivity and selectivity. The localized surface plasmon resonance (LSPR) spectra of Au@Ag nanocubes (NCs) are linearly shifted to a long wavelength with an increasing concentration of ConA. In fact, each Au@Ag NC can act as a nanobiosensor for the quantified detection of trace ConA, which enables the miniaturization of the biosensor system to nanoscale. Furthermore, the results demonstrated the perfect biosensing ability with the dual channel of dark-field microscopy images and LSPR spectra. We expect that this nanobiosensor system can provide an alternative important method for monitoring the specific binding of lectin-sugar at a single nanoparticle surface.