Electrochemical and antimicrobial activity of tellurium oxide nanoparticles

Highlights: • TeO₂ NPs synthesized without using any catalyst by chemical vapour deposition method. • The growth temperature was 410 °C with continuous flow of O_2. • TeO₂ NPs have anti-bacterial activity against E. coli, K. pneumoniae and S. aureus while enhances the growth of S. pyogenes. • TeO₂ shows maximum redox current at pH 7 for phosphate buffer solution. - Abstract: Thin film of tellurium oxide (TeO₂) has been synthesized by chemical vapour deposition method onto indium tin oxide (ITO) coated glass substrate without using any catalyst. XRD pattern of TeO₂ thin film suggests that the structure of TeO₂ changes from amorphous to crystalline (paratellurite) on dispersing into deionized water. Zeta potential measurement reveals a positive surface potential of 28.8 mV. TEM images shows spherical shaped TeO₂ nanoparticles having average particle size of 65 nm. Electrochemical studies of TeO₂/ITO electrode exhibit improved electron transfer owing to its inherent electron transfer property at pH 7.0 of phosphate buffer. Antimicrobial activity of TeO₂ has been studied for gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram negative (Escherichia coli and Klebsiella pneumoniae) bacterial and fungal strains (Aspergillus nizer and Candida albicans). These studies suggest that the TeO₂ NPs inhibit the growth of E. coli, K. pneumoniae and S. aureus bacteria, whereas the same particles enhance the growth of S. pyogenes bacteria.