Abstract
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•Gas-phase evaporation self-assembly of metallic-TiO2 hybrid nanoparticle cluster.•High inhibition zone (> 9 mm) toward E. coli by TiO2 under UV–vis irradiation.•Ag and Cu nanoparticle improved the activity of TiO2 without UV irradiation.•Higher antibacterial activity for Ag/TiO2 than Cu/TiO2 hybrid nanoparticle cluster.•Material performance is correlated with visible light absorption and metal surface area.
Titania-based hybrid nanostructures with homogenous distribution of TiO2 and metal (Ag or Cu) nanoparticles were fabricated using an aerosol-assisted synthetic method for antibacterial applications. E. coli was chosen as the representative bacteria, and the performance was determined based on the inhibition zone diameter (ZOI) in the disk diffusion over different light irradiation, catalyst loading, and composition of catalyst material. Results show that TiO2 nanoparticle cluster was inactive in the absence of UV light irradiation, and a significant inhibition zone was identified under UV–vis irradiation (ZOI = 9.4 mm). Addition of Ag and Cu nanoparticles improved the antibacterial activity of the TiO2-based nanoparticle cluster, and the performance was further enhanced with the increase of catalyst loading. Clear inhibition zone was observed in the dark by using Ag/TiO2 (ZOI = 9.0 mm), and the zone diameter was increased by having UV–vis light irradiation (ZOI = 13.3 mm), confirming metallic nanoparticle in the structure to promote antibacterial activity from the prospects of both photocatalysis and metal ion release. Ag/TiO2 was more active than Cu/TiO2 (ZOI = 10.2 mm) due to the higher absorption of visible light and the higher metal surface area for metal ion-induced surface reaction. These findings highlight the successful fabrication of highly dispersed metal-TiO2 hybrid nanoparticle clusters via gas-phase evaporation-induced self-assembly to achieve high antibacterial performance.