title: Biogenic synthesis of SnO₂ nanoparticles: evaluation of antibacterial and antioxidant activities.
abstract: Nanostructured semiconductors have been of special interest to scientific community due to their peculiar properties. The quantum size effect results in spectacular variation in the optical and vibrational characteristics of nanostructured materials compared to their bulk counterparts. The present work emphasizes an unexploited, cost effective, and environmentally benign method of synthesizing bioactive tin oxide nanoparticles of size from 2.1 nm to 4.1 nm using Saraca indica flower. The XRD pattern and HRTEM images of the samples revealed an increase in particle size with annealing temperature. Fine tuning band gap could be attained as evidenced by the shift of absorption band edge and photoluminescence emission. It is found that oxygen vacancies play an important role on PL emission. The synthesized nanoparticles exhibit antibacterial activity against gram negative bacteria Escherichia coli. The antioxidant activity is evaluated by scavenging free radicals of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH). The efficiency of biogenic SnO₂ nanoparticles as a promising antibacterial agent as well as an antioxidant for pharmaceutical applications is suggested.
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Vidhu
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India. Electronic address: philipdaizy@yahoo.co.in.
authors.forename: Daizy
authors.initials: D
authors.lastname: Philip
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000188:drug therapy; D007887:Fabaceae / Q000737:chemistry; D006801:Humans; D008163:Luminescent Measurements; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D017971:Tin Compounds / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D017971:Tin Compounds; C045358:stannic oxide
keywords: Absorption band edge; Antibacterial activity; DPPH; Photoluminescence; Saraca indica; Tin oxide