title: Synthesis of well-dispersed silver nanorods of different aspect ratios and their antimicrobial properties against Gram positive and negative bacterial strains.
abstract: In the present contribution, we describe the synthesis of highly dispersed silver nanorods (NRs) of different aspect ratios using a chemical route. The shape and size of the synthesized NRs were characterized by Transmission Electron Microscopy (TEM) and UV-visible spectroscopy. Longitudinal and transverse absorptions bands confirm the rod type structure. The experimentally recorded UV-visible spectra of NRs solutions were fitted by using an expression of the extinction coefficient for rod like nano structures under the dipole approximation. Simulated and experimentally observed UV-visible spectra were compared to determine the aspect ratios (R) of NRs. The average values of R for NR1, NR2 and NR3 solutions are estimated to be 3.0 ± 0.1, 1.8 ± 0.1 and 1.2 ± 0.1, respectively. These values are in good agreement with those obtained by TEM micrographs. The silver NRs of known aspect ratios are used to study antimicrobial activities against B. subtilis (gram positive) and E. coli (gram negative) microbes. We observed that the NRs of intermediate aspect ratio (R = 1.8) have greater antimicrobial effect against both, B. subtilis (gram positive) and E. coli (gram negative). The NRs of aspect ratio, R = 3.0 has better antimicrobial activities against gram positive than on the gram negative.
authors.affiliation: Motilal Nehru National Institute of Technology Allahabad, Allahabd 211004, India. animesh@mnnit.ac.in.
authors.forename: Animesh K
authors.initials: AK
authors.lastname: Ojha
authors.forename: Stefan
authors.initials: S
authors.lastname: Forster
authors.forename: Sumeet
authors.initials: S
authors.lastname: Kumar
authors.forename: Siddharth
authors.initials: S
authors.lastname: Vats
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Negi
authors.forename: Ingo
authors.initials: I
authors.lastname: Fischer
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects* / Q000254:growth & development; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012834:Silver / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver