Peptide-gold nanoparticle conjugates have become attractive tools for a variety of applications including drug delivery, targeting, cancer therapy, brain diseases, vaccines, immune modulation, biosensor, colorimetric detection and bio-labeling. However, it is still difficult to produce effective therapeutics that can deliver sufficient concentrations of a specific drug to tumors and avoid off-target effects on healthy cells.
We have developed a new peptide that binds gold and enables the formation of well-designed, shape-and size-tunable gold nanostructures. This peptide contains phenylalanine and lysine amino acids, which are responsible for the attachment of gold ions to peptide nanofibers. The resulting gold-peptide composites are colloidally stable and can be stored as powders without loss of their stability once re-dispersed in water.
The peptide Midas-2, which was selected from a M13 phage-displayed combinatorial peptide library, is effective in producing monodisperse spherical gold nanostructures. The synthesized gold nanostructures are characterized by high-resolution transmission electron microscopy (TEM) with an average diameter of 16 nm, as well as by UV-Vis spectroscopy and X-ray photoelectron spectroscopy.
Moreover, the synthesized gold-peptide composites were tested for their catalytic activity against p-nitrophenol to p-aminophenol. The peptide-gold nanoparticles were found to exhibit an extremely rapid and efficient reduction of p-nitrophenol to the least toxic p-aminophenol in less than 2 min at the concentrations used.
The peptide-gold nanoparticles are highly biocompatible and can be easily modified by chemical, electrochemical or biological means. They are tunable in size and shape, which is important for many applications. This invention provides a simple and efficient strategy to generate hybrid composite nanoparticles, which can be used for drug delivery, nanomedicine and bioimaging.