title: Anomalous antibacterial activity and dye degradation by selenium doped ZnO nanoparticles.
abstract: Selenium doped ZnO nanoparticles synthesized by mechanochemical method were spherically shaped of size distribution of 10.2±3.4 nm measured by transmission electron microscopy. Diffused reflectance spectroscopy revealed increase in the band gap, ranging between 3.47 eV and 3.63 eV due to Se doping in ZnO nanoparticles. The antibacterial activity of pristine and Se doped ZnO nanoparticles was attributed to ROS (reactive oxygen species) generation in culture media confirmed by TBARS assay. Compared to complete inhibition of growth by 0.45 mg/mL of pristine ZnO nanoparticles, the batches of 0.45 mg/mL of selenium doped ZnO nanoparticles exhibited only 51% inhibition of growth of Escherichia coli. The reduced antibacterial activity of selenium doped ZnO nanoparticles was attributed to two opposing factors, e.g., ROS generation for inhibition of growth, countered by sustaining growth of E. coli due to availability of Se micronutrients in culture media, confirmed by inductively coupled plasma mass spectrometer measurement. Higher ROS generation by selenium doped ZnO nanoparticles was attributed to creation of oxygen vacancies, confirmed from green emission peak observed at 565 nm. The impact of higher ROS generation by selenium doped ZnO nanoparticles was evident from enhanced photocatalytic degradation of trypan blue dye, than pristine ZnO nanoparticles.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India. Electronic address: duttafcy@iitr.ernet.in.
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Dutta
authors.affiliation: Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India.
authors.forename: Bhavani Prasad
authors.initials: BP
authors.lastname: Nenavathu
authors.affiliation: Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India.
authors.forename: Soumita
authors.initials: S
authors.lastname: Talukdar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004396:Coloring Agents / Q000737:chemistry*; D003470:Culture Media / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D012643:Selenium / Q000737:chemistry / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D014343:Trypan Blue / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D003470:Culture Media; D017382:Reactive Oxygen Species; D012643:Selenium; D014343:Trypan Blue; D015034:Zinc Oxide
keywords: Antibacterial activity; Doped ZnO NPs; Dye degradation; Reactive oxygen species; Selenium; TBARS assay