Antibacterial Efficacy of Gold and Silver Nanoparticles Functionalized with the Ubiquicidin (29-41) Antimicrobial Peptide

Recent studies have demonstrated that drug antimicrobial activity is enhanced when metallic nanoparticles are used as an inorganic support, obtaining synergic effects against microorganisms. The cationic antimicrobial peptide ubiquicidin 29-41 (UBI) has demonstrated high affinity and sensitivity towards fungal and bacterial infections. The aim of this research was to prepare and evaluate the antimicrobial efficacy of engineered multivalent nanoparticle systems based on silver or gold nanoparticles functionalized with UBI. Spectroscopy techniques demonstrated that NPs were functionalized with UBI mainly through interactions with the -NH2 groups. A significant increase in the antibacterial activity against Escherichia coli and Pseudomonas aeruginosawas obtainedwith the conjugateAgNP-UBI with regard to that of AgNP. No inhibitionof bacterial growth was observed with AuNP and AuNP-UBI using a nanoparticle concentration of up to 182 mu g mL(-1). Nonetheless, silver nanoparticles conjugated to the UBI antimicrobial peptide may provide an alternative therapy for topical infections.