For reprint orders, please contact: reprints@futuremedicine.com Nanomedicine (Lond.) (Epub ahead of print) ISSN 1743-5889 part of Research Article 10.2217/nnm-2016-0232 © 2016 Future Medicine Ltd 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. First draft submitted: 10 June 2016; Accepted for publication: 5 August 2016; Published online: 13 September 2016 Keywords:฀ antibacterial฀peptides฀•฀antibiotics฀•฀antibiotic-resistant฀bacteria฀•฀Au฀NPs฀ •฀Enterococcus faecalis฀•฀Enterococcus faecium฀•฀macrophages฀•฀MRSA฀•฀Staphylococcus aureus฀•฀VRE Functional gold nanoparticle-based antibacterial agents for nosocomial and antibiotic-resistant bacteria OD Growth curves of bacteria Growth time (h) Bacterium Antibacterial Au NPs DVFLG WWWWC Yen-Ling Kuo 1 , Sin-Ge Wang 1 , Ching-Yi Wu 1 , Kai-Chieh Lee 1 , Chan-Jung Jao 1 , Shiu-Huey Chou 2 & Yu-Chie Chen* ,1 1 Department฀of฀Applied฀Chemistry,฀ National฀Chiao฀Tung฀University,฀ Hsinchu฀300,฀Taiwan 2 Department฀of฀Life฀Science,฀Fu-Jen฀ Catholic฀University,฀New฀Taipei฀City฀242,฀ Taiwan *Author฀for฀correspondence:฀ Tel.:฀+886฀3฀5131527 Fax:฀+886฀3฀5723764 yuchie@mail.nctu.edu.tw