Engineering Gram Selectivity of Mixed-Charge Gold Nanoparticles by Tuning the Balance of Surface Charges

• Published in: Angewandte Chemie (International ed.) 2016-07, Vol.55 (30), p.8610-8614
• Main Authors: Pillai, Pramod P., Kowalczyk, Bartlomiej, Kandere-Grzybowska, Kristiana, Borkowska, Magdalena, Grzybowski, Bartosz A.
• Format: Article
• Language: English
• Subjects: antibiotics; catalysis (homogeneous), solar (photovoltaic), bio-inspired, charge transport, mesostructured materials, materials and chemistry by design, synthesis (novel materials), synthesis (self-assembly); Gram specificity; Ligands; Nanoparticles; surface charge
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201602965

Nanoparticles covered with ligand shells comprising both positively and negatively charged ligands exhibit Gram‐selective antibacterial action controlled by a single experimental parameter, namely the proportion of [+] and [−] ligands tethered onto these particles. Gram selectivity is attributed to the interplay between polyvalent electrostatic and non‐covalent interactions that work in unison to disrupt the bacterial cell wall. The [+/−] nanoparticles are effective in low doses, are non‐toxic to mammalian cells, and are tolerated well in mice. These results constitute the first example of rational engineering of Gram selectivity at the (macro)molecular level. Gram‐specific antimicrobial activity: Nanoparticles covered with mixtures of negatively and positively charged ligands in optimal proportions exhibit antibiotic properties that can be engineered specific to either Gram‐positive or Gram‐negative bacteria. Arrows in the experimental images point to the places at which the particles rupture the bacterial cell wall.