Fluorescence Analysis of Antibacterial Activity of ZnO/TiO₂ Electrospun Nanofibers: A Molecular Approach to Reveals the Insights of Physiochemical Interactions of Materials with Bacteria

Fluorescence spectroscopy employed to compute the antibacterial potential of pure ZnO and Titania (TiO₂) loaded ZnO (TiO₂: 2%, 4%, 6%, and 8%) electrospun nanofibers. The study of electrospun nanofibers followed by their structural, morphological and antibacterial properties has been revealed through fluorescence spectroscopy. X-ray diffraction (XRD) analysis of nanofibers calcinated at 600 °C revealed the presence of polycrystalline wurtzite hexagonal crystallographic planes of ZnO with preferred orientation along (101) direction. Scanning electron microscopy (SEM) confirmed that calcination of electrospun nanofibers resulted in smooth and pure ZnO nanofibers due to ethanol evaporation and polyvinylpyrrolidone (PVP) decomposition. Two bacterial strains Escherichia coli and Pseudomonas aeruginosa were used for fluorescence spectroscopy-based evaluation of antibacterial activity of ZnO and TiO₂-ZnO nanofibers. Agar well technique was employed to investigate the antibacterial activity and functioning mechanism of nanofibers against Escherichia coli and Pseudomonas aeruginosa. The consistent zones of inhibition have been observed for pure ZnO and Titania loaded ZnO nanofibers. Fluorescence spectroscopy revealed the insights of bacterial killing with nanofibers. The mechanistic study of interaction between nanofibers and bacterial cells leads to cell membrane breakdown and confirmed with SEM imaged micrographs. Furthermore, the nanofibers calcinated at 600 °C efficiently ruptured the bacteria resulting in higher antibacterial phenomenon as compare to the other nanofiber structures.