We develop protocols to covalently functionalize plasmonic nanoparticles with biomolecules. The versatility of thiol-mediated chemistry allows us to attach virtually any biomolecule to the particles including DNA, proteins, aptamers, and organic receptors. We specifically focus on protocols that functionalize the hot-spots of the particles to achieve optimal molecule-plasmon coupling.
We investigate the coupling between single molecules and plasmons. This coupling modifies the properties of the molecule (e.g. enhancement of fluorescence) but also the properties of the plasmon (e.g. wavelength shifts and broadening). We use these mechanisms to enhance single-molecule signals from enzymes and conformational probes.
We develop next-generation biosensing principles based on plasmonic nanoparticles. Recently, we succeeded in detecting plasmon shifts induced by single molecules on many plasmonic particles in parallel. We develop this principle further toward a single-molecule biosensor that allows for multiplexed, continuous, and specific detection of analyte in complex matrices.