Gamma radiation synthesis of plasmonic nanoparticles for dark field cell imaging

Plasmonic nanoparticles including nanogold and nanosilver were prepared from a convenient gamma radiation route. Biocompatible copolymer chitosan oligomer was used as a template for nanoparticle growing. The obtained gold and silver nanoparticle colloids exhibited excellent water solubility and stability and these nanoparticles were well separated and uniform in size. They exhibited bright scattering light in a dark field owing to the surface plasmon resonance effect and could be easily detected even in a single-particle state. When cultured with cells, they would be internalised into cells and their intense scattering light made cells easily identifiable. These plasmonic nanoparticles obtained from the gamma radiation route could be used as promising contrast agents for multi-colour dark field cell imaging.