Polydopamine-assisted decoration of silver nanoparticles on gold nanorods for photothermal and chemical antimicrobial applications

Bacterial infections have been a serious threat to human health and caused millions of deaths, which brought an urgent requirement for the development of efficient antimicrobial materials. Herein, we prepared AuNRs@PDA@AgNPs nanocomposites by assembling silver nanoparticles (AgNPs) on gold nanorods (AuNRs) with the assistance of polydopamine (PDA). The constructed AuNRs@PDA@AgNPs have good photothermal effects with a temperature raise of ∼28 °C at 150 μg mL−1 under 808 nm laser illumination of 1.0 W cm−2. Meanwhile, the decorated AgNPs provided chemical bactericidal effects, whereas the release of Ag was also enhanced by the light illumination. The minimum inhibitory concentration (MIC) of AuNRs@PDA@AgNPs against the bacteria was 16 μg mL−1, at which AuNRs@PDA@AgNPs can inhibit the bacterial cell viability to 5.3% and 2.0% for E. coli and S. aureus bacteria, respectively. In this work, a novel nanocomposite that realizes synergistic photothermal and chemical sterilization is successfully constructed.