Functional Gold Nanoparticles as Photothermal Agents for Selective-Killing of Pathogenic Bacteria

Abstract

Our aim was to demonstrate that functional gold nanoparticles can be used as photothermal agents for the selective killing of pathogenic bacteria. Gold nanoparticles with polygonal shapes, capable of absorbing near infrared (NIR) light, were generated through a photochemical reaction. Vancomycin, which can bind with the terminal D-Ala-D-Ala moieties of the peptide units of pathogen cell walls, was immobilized on the surface of the gold nanoparticles. The vancomycin-bound gold nanoparticles were used as the photothermal agents for the inhibition of pathogenic bacteria growth, under irradiation of NIR light (808 nm). We have demonstrated that vancomycin-bound gold nanoparticles are capable of selective-binding onto the cell walls of pathogenic bacteria. A large portion (>99%) of bacteria targeted by the gold nanoparticles was destroyed under illumination by NIR light within 5 min owing to suffering from heating. This photothermal approach is effective for the inhibition of pathogenic bacteria cell growth, including Gram-positive bacteria, Gram-negative bacteria and antibiotic-resistant bacteria.