Research Of Superparamagnetism Nano Gamma Fe₂O₃Magnetic Heat Characteristics

It is endless with the progress of the medical research in tumor treatment method. But atpresent the principal means of cancer treatment is still surgery,radiotherapy andchemotherapy. As the research and development about physical medicine and medicalimaging, the physical therapy has gradually become the hotspot of medical engineeringresearch, including heat treatment is one of research focuses in the current domestic andforeign scholars.It is called a tumor thermotherapy that heat the target temperature to41⁴6℃hot to damage cancer cells. Heat the target temperature over56℃which methodfor treatment of tumor is called thermal ablation or eager tumor method. At present RF,laser, focused ultrasound, whole body thermotherapy and isolated perfusion heat treatmentmethod are used commonly. It limits their clinical application,because the tumor targetingability is poor, easy to cause tumor adjacent normal tissue damage. Magnetic mediatedhyperthermia （megnetically mediated hyperthermia, MMH） because of its targeted, can bein alternating magnetic field in vitro induced by hysteresis phenomenon or made into thetumor lesions such as eddy current is local or magnetic magnetic particles generate heat. Magnetic material will be heat conduction to the cancer cells witho ut damaging nearbynormal tissue. The advantages of a very promising makes it one of new generation tumorheat method.The concept of MMH first described by the Gilchrist, etc in1957, and two key factorsneed to be solved. One is high yield and thermal efficiency of the magnetic materials, andthe other one is suitable for clinical and no damage to the human body magnetic fieldgenerating equipment.Magnetic materials heat treatment technology is received wideattention of scholars, because it has the characteristics of universality, high absorption rateand other characteristics. But due to the poor material tumor targeting of the magneticnanoparticles so the application of magnetic mediated hyperthermia is limited. Previousresearch has found that the photosensitizer porphyrin derivatives have good tumor tropism.So the affinity of porphyrin derivatives of tumor tissue to porphyrin derivatives can beused as a carrier to transport superparamagnetism nanoparticles to combine with tumortissue.Then repeated magnetization Under the appropriate magnetic field,so nanoparticleshave a hysteresis effect to heat.The heat will transfer to the cells and tissues, so as toachieve heat inactivated tumor cells and organization. The magnetic field design,fabrication of nanoparticles and heat production of nano materials was discussed in thearticle, provide support for the future research of hyperthermia with superparamagnetismnano material embedded in the blood porphyrin.First we design of sine wave magnetic device for magnetic-induced tumor hyperthermiain order to design a magnetic field generator for magnetic induction hyperthermia. We usethe555chip as the core and use of RC oscillator circuit making the sine wave, thenamplify the current, and when we add a external coil it generate the required magneticfield.As a result,the instrument can produce50-100kHz sine wave magnetic field, and theMagnetic-nanoparticles can heat.In conclusion that the circuit can heat themagnetic-nanoparticles and is low cost and high accuracy.It is the instrument for thattumor magnetic hyperthermia research of follow-up.Second,we studyed about preparation of nano-iron oxide. We used those Solid phasegrinding, heating precipitation and homogeneous precipitation, several methods to prepare the superparamagnetic nanoparticles （γ-Fe₂O₃）for drug embedded, and compared thepreparation methods with time, particle size, purity.We used FeCl3·6H2O、FeCl2·4H2O、NaOH、Fe（NO3）3·9H2O and so on as material, respectively, to prepare superparamagneticnanoparticles by solid-phase ginding, chemical precipitation and homogeneousprecipitation, and observed the particle size by scanning electron microscopy. As a result,solid-phase grinding may cause the particle lattice distortion and reunion serio us. Derivedfrom chemical precipitation particle the size is good, affected by many factors. Thehomogeneous precipitation method can be adjusted nanoparticle formation rate and theshape is spindle.So we could get the conclusion that the chemical precipitation method issimple for laboratory to prepare ofsuperparamagnetic nanoparticles （γ-Fe₂O₃）.The last,we made a easerch about Gamma Fe₂O₃in the magnetic field whose surfacemodificated by oleic acid.Research about producing heat effect of gamma Fe₂O₃aftersurface modified by oleic acid in the alternating magnetic field.We took15mg of gammaFe₂O₃whose surface modified made into oleic acid solution,and then put the solution inthe magnetic field with different current of10A,20A,30A. Observe whether magneticnanoparticles is hot and the effection of the different current to the heat of nanoparticles.Experiment repeated three times and using SPSS software analysis results.As aresult,the heat in the alternating magnetic field of super paramagnetic nanoparticle aftersurface modification is related to the current of the magnetic field.So we get theconclusion that super paramagnetic nanoparticle after surface modification can heat in thealternating magnetic field. As the same time the magnetic field current can be adjusted fortemperature control. The research provides support for the further study about the heat inthe alternating magnetic field of super paramagnetic nanoparticle embedded in the bloodporphyrin and its derivatives.This team is currently looking for the super paramagnetic nanoparticles, stimulatethermogenesis theory of the magnetic field parameters and validated its correctnessthrough the experiment. Found easily super paramagnetic nanoparticles modified surfacemodification method, and proved that the magnetic field current super paramagneticnanoparticles produced thermal efficiency. In subsequent experiments, we will have super paramagnetic embedding of nanomaterials, and the optimal excitation to produce thermalparameters, optimal thermal efficiency is further explored. This team are doing researchfor subsequent experiments, blood porphyrin and its derivatives embedding superparamagnetic nano particles in the magnetic field heat treatment method of the researchprovides the basis.