title: Effect of iron oxide and gold nanoparticles on bacterial growth leading towards biological application.
abstract: BACKGROUND
  Nanoparticle-metal oxide and gold represents a new class of important materials that are increasingly being developed for use in research and health related activities. The biological system being extremely critical requires the fundamental understanding on the influence of inorganic nanoparticles on cellular growth and functions. Our study was aimed to find out the effect of iron oxide (Fe3O4), gold (Au) nanoparticles on cellular growth of Escherichia coli (E. coli) and also try to channelize the obtained result by functionalizing the Au nanoparticle for further biological applications.
  
  
  RESULTS
  Fe3O4 and Au nanoparticles were prepared and characterized using Transmission electron microscopy (TEM) and Dynamic Light Scattering (DLS). Preliminary growth analysis data suggest that the nanoparticles of iron oxide have an inhibitory effect on E. coli in a concentration dependant manner, whereas the gold nanoparticle directly showed no such activity. However the phase contrast microscopic study clearly demonstrated that the effect of both Fe3O4 and Au nanoparticle extended up to the level of cell division which was evident as the abrupt increase in bacterial cell length. The incorporation of gold nanoparticle by bacterial cell was also observed during microscopic analysis based on which glutathione functionalized gold nanoparticle was prepared and used as a vector for plasmid DNA transport within bacterial cell.
  
  
  CONCLUSIONS
  Altogether the study suggests that there is metal nanoparticle-bacteria interaction at the cellular level that can be utilized for beneficial biological application but significantly it also posses potential to produce ecotoxicity, challenging the ecofriendly nature of nanoparticles.
authors.affiliation: Department of Microbiology, University of Kalyani, Nadia, West Bengal, India.
authors.forename: Saptarshi
authors.initials: S
authors.lastname: Chatterjee
authors.forename: Arghya
authors.initials: A
authors.lastname: Bandyopadhyay
authors.forename: Keka
authors.initials: K
authors.lastname: Sarkar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D005290:Ferric Compounds / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism; D006046:Gold / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000627:therapeutic use* / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D005290:Ferric Compounds; C000499:ferric oxide; D006046:Gold; D005978:Glutathione