Luminescent gold nanoparticles capped with tiopronin derivatives

This paper describes the preparation of gold nanoparticles passivated with different tiopronin-like thiol peptide derivatives. The average size of these gold particles falls into the range of 1.7-2.1 nm with narrow dispersity. All the gold nanoparticles exhibit near-IR luminescence in the spectral range of 700-950 nm. The luminescence properties of the gold nanoparticles depend on the structure of the capping ligands; those capped with polar thiol peptides give weaker luminescence in water. Reducing the packing efficiency of the passivating layer by bulky ligands is likely to facilitate the luminescence quenching effects of foreign quenchers and hence weaken the luminescence of the gold nanoparticles.