Experimental Study On Killing Effects Of Melanoma Cell A375 In Vitro By Nanosecond Pulsed Magnetic Field Combined With Targeted Iron Oxide Nanoparticles

Pulsed magnetic field(PMFs)technology,as a new tumor treatment technology,has outstanding advantages such as non-contact and non-thermal.This method can effectively slow down the growth rate of tumors without cooperating with drugs for chemotherapy and radiotherapy.It is a promising research direction in the field of cancer treatment.However,when the intensity of the pulsed magnetic field is low or high,there are often problems such as poor curative effect and poor electrical safety,which limit the application and promotion of pulsed magnetic field treatment technology to a certain extent.Targeted nano-iron oxide(SPIONs-FA)materials with excellent magnetic properties have been proven to specifically recognize tumor cells and perform targeted binding.In order to improve the electrical safety and other issues in the treatment of pulsed magnetic field,by analogy with nano-particles that can enhance cell electroporation,this article first proposes a method of nanosecond pulsed magnetic field combined with targeted nano-iron oxide to treat tumors.And the effectiveness of this method is verified through experiments.This article also preliminarily puts forward the reasons for cell inactivation caused by this combined method by combining experiments with existing theories.First of all,this article builds the high-frequency pulse generator required for the experiment by using the R-C charging and discharging principle and Archimedes spiral coils and other components.And according to the strength of the cell killing effect,the different pulse magnetic field amplitudes,the number of pulses,and the pulse frequency parameter values in the string are selected for the five experiments.Taking human melanoma cell A375 cultured in vitro as the experimental object,CCK-8 was designed to detect cell viability and Annexin V-FITC/PI double staining to detect cell apoptosis and necrosis rate.Experimental methods such as propidium iodide(PI)macromolecular nucleic acid dye fluorescent staining to detect cell perforation rate,scanning electron microscope(SEM)to detect cell membrane ultrastructure and other experimental methods.Secondly,on the basis of determining the safe concentration of SPIONs-FA,this article studied the changes of cell viability,cell apoptosis and necrosis rate and cell perforation ratio under different pulse parameters.In this paper,the relationship between different pulse parameters and cell viability,apoptosis and necrosis rate and the ratio of perforated cells under single pulse factors was established by using the Logistic curve model method.The results showed that although the experimental results such as cell viability basically did not change with the pulse frequency in the train,the viability and the pulse magnetic field amplitude were negatively correlated with the number of pulses,while the apoptosis and necrosis rate and the perforation ratio were positively correlated with the pulse parameters.And the combined treatment method has a stronger cell inactivation effect.This article also uses SEM to observe the processed A375 and human red blood cells,etc.,to prove that the combined method can change the ultrastructure of the cell membrane.Finally,on the basis of the previous experimental results,this paper compares and analyzes the relationship between cell viability and changes in the rate of apoptosis and necrosis,as well as the relationship between cell viability and changes in the ratio of perforated cells.The results showed that ns PMFs alone or combined treatment of cells can induce apoptosis and necrosis of the cells,resulting in a decrease in cell viability.Through the analysis and comparison of the experimental results,it is found that the magnetic field can cause the cell membrane to be perforated by force,thereby causing the cell activity to change.In summary,the nanosecond pulsed magnetic field combined with targeted nano-iron oxide can more effectively perforate and inactivate cells,thereby reducing the pulse intensity required for treatment and improving the electrical safety of the pulsed magnetic field for tumor treatment.This combined method is expected to provide a new physical method that is better tolerated by patients for tumor treatment,which is of great significance.