The improved antibacterial efficiency of a zinc phthalocyanine when embedded on silver nanoparticle modified silica...

This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO₂ NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO₂, Ag-SiO₂, Pc-SiO₂ and Pc@Ag-SiO₂ NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO₂ and Pc@Ag-SiO₂ NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO₂ NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO₂ NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO₂ NFs do not exhibit any antibacterial activity while the Ag-SiO₂ and Pc@Ag-SiO₂ NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.