Small gold nanocomposites obtained in reverse micelles as nanoreactors. Effect of surfactant, optical properties and activity against Pseudomonas aeruginosa

Abstract

In this work, we report the formation of small gold nanoparticles (AuNPs) functionalized with a synthetic antimicrobial peptide (AMP) using cysteine as a linker in order to enhance its bactericidal activity. We evaluated the effect of two different nanoreactors and their inter-droplet interactions to form small and monodispersed AuNPs. The systems used as nanoreactors were Tergitol and sodium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles (RMs) in isooctane. As a result of this work, we obtained spherical, monodisperse and small (2–6 nm) gold nanoparticles with intense surface plasmon resonance (SPR), and by “serendipity”, we found medium gold clusters that were determined by fluorescence emission at different excitation wavelengths. The nanoparticles obtained were linked with the AMP, forming AuNP–AMP nanocomposites showing an excellent minimum bactericidal concentration (MBC) against Pseudomonas aeruginosa, an opportunistic bacterium that affects several populations around the world. Thus, our results offer possible alternatives for new clinical products, such as antibacterial fabrics and bandages loaded with AMPs through a metal matrix.