Gold nanoparticles conjugated to benzoylmercaptoacetyltriglycine and L-cysteine methylester

Benzoyl-protected mercaptoacetyltriglycine, a synthetic precursor used in the preparation of Technetium-99m-mercaptoacetyltriglycine, a radiopharmaceutical for renal tubular function and L-cysteine methylester, a small, non-zwitterionic amino acid derivative, were used as capping agents of gold nanoparticles obtained by borohydride reduction method. The capped gold nanoparticles composites were prepared from aqueous solutions and characterized by UV-Vis, infrared and Raman spectra and Transmission Electron Microscopy images. The presence of the ligands and its different binding mode to the particles as a consequence of the benzoyl-protection of the thiol group in benzoyl-protected mercaptoacetyltriglycine were evidenced from infrared and Raman spectra. The stability on aging in water solution of the formed composites is discussed from the obtained UV-Vis spectra.