Synthesis of Electrospun TiO2 Nanofibers and Characterization of Their Antibacterial and Antibiofilm Potential against Gram-Positive and Gram-Negative Bacteria

Abstract

Recently, titanium dioxide (TiO₂) nanomaterials have gained increased attention because of their cost-effective, safe, stable, non-toxic, non-carcinogenic, photocatalytic, bactericidal, biomedical, industrial and waste-water treatment applications. The aim of the present work is the synthesis of electrospun TiO₂ nanofibers (NFs) in the presence of different amounts of air-argon mixtures using sol-gel and electrospinning approaches. The physicochemical properties of the synthesized NFs were examined by scanning and transmission electron microscopies (SEM and TEM) coupled with energy-dispersive X-ray spectroscopy (EDX), ultraviolet-visible spectroscopy and thermogravimetric analyzer (TGA). The antibacterial and antibiofilm activity of synthesized NFs against Gram-negative <i>Pseudomonas aeruginosa</i> and Gram-positive methicillin-resistant <i>Staphylococcus</i><i>aureus</i> (MRSA) was investigated by determining their minimum bacteriostatic and bactericidal values. The topological and morphological alteration caused by TiO₂ NFs in bacterial cells was further analyzed by SEM. TiO₂ NFs that were calcined in a 25% air-75% argon mixture showed maximum antibacterial and antibiofilm activities. The minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) value of TiO₂ NFs against <i>P. aeruginosa</i> was 3 and 6 mg/mL and that for MRSA was 6 and 12 mg/mL, respectively. The MIC/MBC and SEM results show that TiO₂ NFs were more active against Gram-negative <i>P. aeruginosa</i> cells than Gram-positive <i>S. aureus</i>. The inhibition of biofilm formation by TiO₂ NFs was investigated quantitatively by tissue culture plate method using crystal violet assay and it was found that TiO₂ NFs inhibited biofilm formation by MRSA and <i>P. aeruginosa</i> in a dose-dependent manner. TiO₂ NFs calcined in a 25% air-75% argon mixture exhibited maximum biofilm formation inhibition of 75.2% for MRSA and 72.3% for <i>P. aeruginosa</i> at 2 mg/mL, respectively. The antibacterial and antibiofilm results suggest that TiO₂ NFs can be used to coat various inanimate objects, in food packaging and in waste-water treatment and purification to prevent bacterial growth and biofilm formation.