Effects Of Nanomaterials On The DNA And Biophysical Properties Of 293T Cells

Nanomaterials have unique quantum and size effects as well as high surface activity,larger specific surface area and extraordinary adsorption,dispersion and aggregation capacities.These properties make them find a myriad of promising applications in the fields of biotechnology,medicine,chemical industry,etc.Silver nano-particles are one of the most commonly used nanomaterials because of their strong antibacterial properties;graphene oxide a kind of nanomaterial that is very promising in biological applications such as drug delivery and biosensors.In the meanwhile,researchers have discovered that nanomaterials could induce cell apoptosis and gene change.Therefore people begin to pay attention to the potential toxicity of silver nano-particles and graphene oxide to cells.As a result,research regarding the safety of silver nanoparticles and graphene oxide is becoming a hot spot.In this project,we selected silver nano-particles and graphene oxide sheets as typical nanomaterials and taken the human kidney epithelial cells(293t)as model cells,to study the effect of nanomaterials on DNA and biophysical properties of cells.First,the effects of silver nanoparticles and graphene oxide sheets on the cell viability was investigated by observing the morphology of cells and using MTT or CCK8 assays.Second,real time PCR was used to detect genes related Base Excision Repair pathway including APE1 gene,OGG1-t gene and UNG-t gene,after the exposure of the cells to silver nanoparticles and graphene oxide sheets.Third,DNA damage of the cells after the treatment with these two types of nanomaterials were evaluated using single cell gel electrophoresis.Finally,biophysical properties of the cells before and after the treatment with nanomaterials were measured using atomic force microscopy.The results showed that(1)the cytotoxicity of silver nano-particles and graphene oxide sheets on 293 T cells increased with the dose of the nanomaterials;(2)no observable effect of silver nanoparticles on the expression level of APE1,OGG1-t and UNG-t genes was detected;(3)graphene oxide sheets downregulated the expression of APE1 gene,upregulated the expression of UNG-t gene,but had no effect on the expression of OGG1-t gene;(4)DNA damage of 293 T cells induced by silver nano-particles increased with the dose of the nanoparticles;(5)graphene oxide nanosheets incuded DNA damage of 293 T cells,but no dose-dependency was observed;(6)after the treatment by silver nano-particles,the Young's modulus and the maximum adhesion force of 293 T cells showed no change,however the plasticity index was changed to two different values when the concentration of silver nanoparticles reached 40 ?g/mL;and(7)after the treatment by graphene oxide sheets,the plasticity index of 293 T cells decreased with the increase of the dose of nanomaterials.In this paper,we studied the DNA damage,biophysical properties and cell toxicity of 293 T cells induced by silver nano-particles and graphene oxide systematically,the experimental results showed that the cytotoxicity of silver nano-particles and graphene oxide on 293 T cells was strong,which induced the changes of biophysical properties.This paper provided the basis for the safety of nano materials research and application.