Functional gold nanoparticle-based antibacterial agents for nosocomial and antibiotic-resistant bacteria

Aim: Medical treatments for bacterial-infections have become challenging because of the emergence of antibiotic-resistant bacterial strains. Thus, new therapeutics and antibiotics must be developed. Materials & methods: Arginine and tryptophan can target negatively-charged bacteria and penetrate bacterial cell membrane, respectively. Synthetic-peptides containing arginine, tryptophan and cysteine termini, in other words, (DVFLG) 2 REEW 4 C and (DVFLG) 2 REEW 2 C, as starting materials were mixed with aqueous tetrachloroauric acid to generate peptide-immobilized gold nanoparticles (i.e., [DVFLG] 2 REEW 4 C-AuNPs and [DVFLG] 2 REEW 2 C-AuNPs) through one-pot reactions. Results & discussion: The peptide immobilized AuNPs exhibit targeting capacity and antibacterial activity. Furthermore, (DVFLG) 2 REEW 4 C-AuNPs immobilized with a higher number of tryptophan molecules possess more effective antibacterial capacity than (DVFLG) 2 REEW 2 C-AuNPs. Nevertheless, they are not harmful for animal cells. The feasibility of using the peptide-AuNPs to inhibit the cell growth of bacterium-infected macrophages was demonstrated. Conclusion: These results suggested that the proposed antibacterial AuNPs are effective antibacterial agents for Staphylococci, Enterococci and antibiotic-resistant bacterial strains.