Bactericidal action of N doped ZnO in sunlight Biointerface research in applied chemistry

Rajashri Karmali, Amruta Bartakke, Vrinda Borker, Koyar Rane
2011 unpublished
ZnO based fabrics for antibacterial activity is based on absorbance in the UV region of the electromagnetic spectrum, process requiring activation under UV light. In the present study, ZnO is synthesized by hydrazinated oxalate method. The synthesis introduces nitrogen in the lattice of ZnO which shifts its absorbance in the visible region. This N doped ZnO shows enhanced biocidal activity towards Escherichia coli. The textiles based on N doped ZnO can be effectively used as antimicrobial under
more » ... antimicrobial under solar radiations. Abstract Keywords: zinc oxide, antibacterial properties, Escherichia coli, disk diffusion, minimum inhibitory concentration There is a tremendous increase in the rate and spread of infectious diseases, as well as in the number of antibiotic resistant microorganisms. It has thus become more important to prevent the infections than to cure them. The various inorganic metal oxides such as TiO 2 , ZnO, MgO and CaO are of particular interest as they are not only stable under harsh process conditions, but also generally regarded as safe materials to human beings and animals [1-3]. The infectious agents are many times carried by clothes. Hence the need is to design textiles with antimicrobial properties. ZnO is effective against a wide range of microorganisms [4-6] and so the fabrics treated with ZnO prove to be resistant to a large number of microbial strains. ZnO treated cotton fabrics [7] are widely studied for antibacterial activity. ZnO being a wide band gap semiconductor is extensively studied as an antimicrobial agent due to its photocatalytic activity under UV light. ZnO coated fabrics are also used as UV absorbers [8-9]. In the recent years, visible light absorbing photocatalysts with Ag/AgBr/TiO 2 have proved to be effective in killing Staphylococcus aureus and Escherichia coli [10]. Aerogel-derived halogenated (Cl 2 and Br 2) adducts of nanocrystalline metal oxides such as MgO and CaO are reported to be successful against Escherichia coli, Bacillus cereus and Bacillus globigii as well as for decontaminating MS2 bacteriophage in dry powder form or as an aqueous slurry [11]. To increase the photocatalytic activity of ZnO, it is doped with different metals and non-metals [12-15]. Among the non-metals, Nitrogen is regarded as the most promising dopant, exhibiting properties similar to oxygen [16]. In the present study, an attempt is made to synthesize N doped ZnO by hydrazinated oxalate method and to study its antibacterial activity against E. coli, a Gram negative bacterial species. The results are also compared with the antibacterial activity of commercially available ZnO.