Functional gold nanoparticles as photothermal agents for selective-killing of pathogenic bacteria

Aims: Our aim was to demonstrate that functional gold nanoparticles can be used as photothermal agents for the selective killing of pathogenic bacteria. Materials & methods: 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). Results & discussion: 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. Conclusions: This photothermal approach is effective for the inhibition of pathogenic bacteria cell growth, including Gram-positive bacteria, Gram-negative bacteria and antibiotic-resistant bacteria.