To Study the Effect of Silver Nanoparticle on Genetic Material to Assess its Potential Toxicity

Abstract

The progress in nanotechnology has resulted in many products containing nanoparticles (NPs) due to the unique and novel size-related physico-chemical properties. The novel propertiesof silver Nanoparticle (AgNP) have been exploited in a wide range of applications viz, medicine, cosmetics, renewable energies, environmental remediation and biomedical devices. The increased human and environmental exposure to nanoparticles has raised concern for safety which can be addressed only if conclusive laboratory data are available. The toxicity assessment results of nanoparticles are questioned as to if they really represent thein-vivo condition due to the agglomerating tendency of nanoparticles. Thus, it is necessary to evaluate the dose dependent exposure assays considering the mono-dispersed or agglomeration status of NPs. Present study focuses on in- vitro assessment of genetic toxicity of the Ag NPs, along with the partico-kinetics of Ag NPs in water and culture media in order toextrapolate the behavior of NPs in short term cultures.Genetic toxicity assessment is the evaluation of an agent for its ability to induce genetic changes i.e. alterations in the genetic material that can be detected at various levels viz., molecular level or chromosome level. The chromosome aberration assay was performed using cultured blood lymphocyte;it was found that AgNP induces significantly higher levels of CA per cell. AgNP induce chromatid-type, gaps and breaks type aberrations at relatively high dose levels. Clastogenic activities were compared among different concentrations of AgNP. In order to study the direct DNA interaction, AgNPs binding with DNA was studied by UV-visible, fluorescence spectroscopy. By the analysis of UV-visible titration it was found that AgNP can form a new complex with double-helical DNA. The fluorescence emission spectra of intercalated ethidium bromide (EtBr) with increasing concentration of AgNP at 25°C represented a significant reduction of the EtBr binding and thus quenching of EtBr fluorescence. Spectroscopic results represented that binding of AgNPs to DNA resulted in significant changes in the structure and conformation of DNA in a concentration dependent manner and quenching of EtBr fluorescence intensity. Also the partico-kinetics of the particle was studied in water as well as media with the help of UV-Vis spectroscopy for 24 hours. Results of the present study may provide useful information to generate laboratory data in order to support the regulatory agencies to issue necessary safety guidelines regarding use of AgNPs, where the advantages of technology is not at par with safety assessment.