Fully Zwitterionic Nanoparticle Antimicrobial Agents through Tuning of Core Size and Ligand Structure.

Zwitterionic nanoparticles are generally considered nontoxic and noninteracting. Here, we report effective and selective antimicrobial activity of zwitterionic gold nanoparticles (AuNP) through modulation NP size and surface charge orientation. Using a set of 2, 4, and 6 nm core AuNPs, increasing particle size increased antimicrobial efficiency through bacterial membrane disruption. Further improvement was observed through control of the ligand structure, generating antimicrobial particles with low hemolytic activity and demonstrating the importance of size and surface structure in dictating the bioactivity properties of nanomaterials.