Label-free Biosensing Based on Single Gold Nanostars as Plasmonic Transducers

Gold nanostars provide high sensitivity for single nanoparticle label free biosensing The nanostars present multiple plasmon resonances of which the lower energy ones, corresponding to the nanostar tips and core-tip interactions are the most sensitive to environmental changes streptavidin molecules are detected upon binding to individual biotin modified gold nanostars by spectral shifts in the plasmon resonances Concentrations at low as 0 1 nM produce a shift of the tip related plasmon resonances of about 2 3 nm (5 3 meV)