Antibacterial Activity of In Situ Generated Silver Nanoparticles in Hybrid Silica Films

Herein we present silver nanoparticles (AgNPs)-doped inorganic–organic hybrid silica films on glass and polypropylene substrates. A hybrid inorganic–organic silica sol in alcoholic medium was prepared at room temperature using TEOS, GLYMO, and APTES. Silver nanoparticles were generated in situ within the hybrid silica sol. AgNPs-SiO2 film was obtained by dip coating method following drying at 80◦C. FTIR spectra shows several vibrational bands of the hybrid silica network and amine functionalization. AgNPs formation was observed from the XRD spectra of the dried film. UV–Visible spectra show sharp surface plasmon resonance (SPR) band centered at 412 nm arising from the evenly distributed silver nanoparticle inside the silica film that was supported by morphological characterization. Both the coated films showed good antibacterial activity against E. coli bacterial strain by forming a zone of inhibition in the agar diffusion test. The antibacterial efficiency for coated glass and polypropylene was 72.5% and 83.75%. This coating approach provides a straight-forward solution to prepare antibacterial coatings on various substrates especially on plastics, where low temperature processing is necessary.