Dose Effect Of Killing Effect Of Targeted Gold Nanorods Combined With Nanosecond Pulsed Electric Fields On A375 Cells

Nanosecond pulsed electric fields(ns PEFs),as a new type of tumor therapy with low side effects,can inhibit the growth of tumor cells without chemotherapy and radiotherapy,which has important research significance and application prospects.Because of the short width of ns PEFs,ns PEFs can effectively induce cell apoptosis,but it also requires a higher electric field strength to achieve effective treatment.During the ns PEFs treatment,a higher electric field strength may cause discharge near the tissue and cause burns,which may cause electrical safety problems.Gold nanorods with rod-like structure have been found to enhance cell electroporation effects,but few researches studied gold nanorods combined with ns PEFs.Therefore,in order to improve the electrical safety of traditional ns PEFs treatment,for the first time,this paper offers a method of targeting gold nanorods combined with ns PEFs to treat tumors.The feasibility of this method was verified through experiments and simulations.Folic ancid-modified gold nanorods was used to target A375 cells in this study,which was characterized by TEM,UV-visible spectroscopy,and dark-field imaging.Subsequently,this study studied cell viability under different pulse parameters based on safe concentration of gold nanorods.And the relationship between single pulse factor,pulse energy density and cell viability were established by Logistic model.The results show that the targeted gold nanorods have a better anti-tumor efficacy which can achieve effective killing effects with a lower electric field strength and pulse energy density.Under the guidance of cell viability experiments,this article further studied the effects of the combined treatment on cell apoptosis and necrosis under different pulse parameters by Annexin V-FITC/PI double staining methods,and the dose effects of apoptosis and necrosis were established respectively.The feasibility of this combined treatment was further proved by Caspase-3 and cell cycle experiments.The results show that targeting gold nanorods can improve the cell apoptosis and Caspase-3 activation more effectively,and the cell cycle can be blocked in the S phase,which inhibit the proliferation of tumor cells.In order to further study the theoretical mechanism of the effect of gold nanorods on cell electroporation,this paper established a simulation model of single cells and gold nanorods through Comsol Multiphysics finite element software.The results show that the addition of targeted gold nanorods can more effectively enhance the field strength of the cell membrane,increase the pore density,pore radius and pore flux of the inner and outer membranes of the cell,which further reveal the mechanism of targeting nanorods to enhance electroporation effect.Finally,in vitro 2D simulated tissue ablation experiment was performed based on the guidance of cell experiments and simulations,the variation rules of ablation area and threshold field strength under different pulse parameters were also obtained.And a normalized relationship between ablation area,field threshold and multipulse factors was established.The results show that targeting gold nanorods can increase the ablation area and reduce the threshold field strength more effectively,whicn can improve the electrical safety of ns PEFs treatment,provides guidance for subsequent live animal experiments and also shows potential clinical application prospects.