| Purpose: Electrical impedance method is based on different environments,the cell resistance and capacitance with different frequency changes,is a non-invasive,practical technology.In this paper,the impedance response of gastric cancer cell MGC803 and the toxicity of nano-titanium in cell suspension were studied.The application of impedance spectroscopy and its analytical technique in cytotoxicity evaluation was discussed.From the electrical point of view,electrical impedance in the evaluation of cytotoxicity is feasibility.Methods: In this paper,firstly,the impedance of the human gastric cancer cell MGC803 and the single concentration of nano-titanium were measured by the Agilent 4294 A impedance analyzer and the parallel measuring chamber in the frequency range of 40Hz-100 MHz.Then,the model was obtained by constructing the binomial Cole-Cole model and the equivalent circuit model.The characteristic parameters of the model were extracted and the nonlinear least squares curve was used to fit the analysis.Finally,the impedance spectra and the Cole-Cole models parameters of the human gastric cancer MGC803 cell suspension and nano-titanium group are obtained.The difference of characteristic parameters was compared.The feasibility and specific implementation details of the evaluation of the cytotoxicity of nanometer titanium dioxide under the experimental conditions were discussed.Result:1.The electrical properties of human gastric cancer cell line MGC803 have volume fraction dependency,that is,with the increase of volume fraction,the electrical impedance and the imaginary part(Re Z and Im Z)in the electrical impedance spectrum gradually decrease,and the characteristic frequency(fC1,fC2)almost unchanged.2.Dose-dependence affects the electrical properties of nano-titanium dioxide on human gastric cancer MGC803 cells.with the increase of the dose of nano-TiO2,electrical impedance increments(?Z1,?Z2)decreases.The nano-titanium of 150 ?g/ml and 300 ?g/ml decreases the first electrical impedance increment(?Z1),which were reduced by 6.56% and 8.2%(P<0.001),respectively,the second electrical impedance increment(? Z2)were reduced by 18.18% and39.39%(P<0.001).3.Nano-titanium dioxide increased the characteristic frequency(fC1,fC2)of gastric cancer MGC803 cells.150 ?g/ml and 300 ?g/ml nano-titanium of the first characteristic frequency ofwere in increased by 6.28% and 23.43%(P<0.001),which the second characteristic frequency(fC2)were increased by 19.74% and 29.67%(P<0.001).4.The effect of nano-titanium dioxide on the electrical properties of gastric cancer MGC803 cells is to reduce the cell membrane and nuclear membrane resistance and increase its electrical conductivity.150 ?g/m land 300 ?g/ml nano-titanium of the cell membrane(Cm)and cell extracellular resistance(Re)decreased by 8.13% and 16.26%,23.08% and 38.46%(P<0.001),which cytoplasmic resistance(Rcyt)and the cytoplasmic resistance across the nucleus(Rsh)were increased by 29.41% and 35.29%,4.93% and 28.22%(P <0.001).5.Observed by electron microscopy,300 ?g/ml nano-titanium dioxide had extracellular accumulation,through the cell membrane,and existed in the cytoplasm on the MGC803Conclusion: The electrical impedance spectroscopy(EIS)technique was used to detect the toxic effect of nano-titania on gastric cancer cell line MGC803.Based on the mathematical model and the change of the equivalent circuit model,the effect of nano-titania on the electrical impedance of the cell membrane and nuclear membrane was studied.The cytotoxic effect of titanium dioxide provides a quantitative electrical evaluation method for the possibility of cytotoxicity studies. |
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