| PART I PREPARATION OF POLYMETHYLMETHACRYLATE-FE3O4 AND EVALUATION THE HEATING EFFICIENCY IN VITROObjective we develop an injectable,liquid to solid phase transitional magnetic material,Polymethylmethacrylate(PMMA)-Fe3O4,explore their physical characteristics and evaluate the heating efficiency in vitroMethod Four kinds of cement were prepared by mixing the PMMA,MMA liquid with the different proportion of Fe3O4nanoparticles(PMMA-0?PMMA-5c?PMMA-10c?PMMA-15c).The microstructure of PMMA-Fe3O4 was tested using scanning electron microscope and the element analysis was observed by an energy dispersive X-ray spectrometer.The magnetic properties of Fe3O4 nanoparticles and PMMA-Fe3O4 powder were tested by Physical Property Measurement System(PPMS-9)at room temperature.The liquid PMMA-Fe3O4 was injected into the Na Cl to observe the progress of liquid-solid phasetransformation.PMMA-Fe3O4 with different iron contents we exposed to the altering current magnetic field to evaluate the heating efficiency in vitro.Choosing the best iron content for next experiment.Results scanning electron microscope showed that the Fe3O4 nanoparticles were evenly distributed in PMMA.The element mapping of PMMA-Fe3O4 showed that every element was well dispersed in PMMA and the corresponding molecular percentages for C,O and Fe were 48.64,40.90,10.46%,respectively.The Fe3O4 nanoparticles and the PMMA-Fe3O4 were ferromagnetic.The saturation magnetization value(Ms)for the Fe3O4 nanoparticles?PMMA-Fe3O4 were-15.3,-0.3emug-1 and the coercive force(Hc)were 126.9,64.5Oe.Liquid PMMA-Fe3O4 could be injected from syringe.When contacted with Na Cl,PMMA-Fe3O4 would not be defeated and dispersed.When exposed to the altering current magnetic field in vitro,the magnetic PMMA-Fe3O4 generated heat.The 10%PMMA(PMMA-10c)was the best choice for next experiment.The increased temperature of excised bovine liver was positively correlated to the iron content and time.The ablated liver tissue area for 0.1ml 10%PMMA-Fe3O4 was 1.24±0.28,1.70±0.57,2.76±0.31,4.17±1.07cm2Conclusions The injectable and fast liquid-solid phase transitional PMMA-Fe3O4 is prepared.Fe3O4 Nanoparticles are evenly distribute in PMMA.The setting performance of PMMA-Fe3O4 is good,the settingtime is fast and its high efficiency for tumor hyperthermia therapy is confirmed in vitro.PART ? ULTRASOUND VISUAL MAGNETIC HYPERTHERMIA ABLATION OF TUMOR USING INJECTABLE PMMA-Fe3O4Objective To study the heating efficiency in MB-231 human breast cancer xenograft in nude miceMethod The PMMA-Fe3O4 was prepared as previously,MB-231 breast cancer xenograft model was obtained in nude mice,In this tumor model,PMMA-Fe3O4 was injected using guided ultrasound imaging.After that,CT images were acquired to observe the position of PMMA-10 c.Then,the nude mice were exposed to the altering current magnetic field for 180 s and the surface temperature of tumor was obtained by infrared thermometer.After the magnetic hyperthermia ablation,the macroscopic images of nude mice and the HE staining were studied.The nude mice had no treatment as control group.Results After 4 weeks,the tumor volume reached to0.453±0.109cm3 which were used to the next experiment.0.1ml PMMAFe3O4 was injected precisely using guided ultrasound imaging.After theinjection,the computer tomography images showed that it was well confined in the tumor tissues without any leakage.The surface temperature of the tumor increased with the time when exposed to the altering current magnetic field and reached to 53.05±3.18oCat 180 s.On the fifteenth day,the scab separated from mice and fell down.The pathology images showed tumor tissue that received PMMA-10 c followed by ablation that disorder tissue with distinct destructed cells existed.While for the nude mice had no treatment,the tumor volume had an upward tendency.The HE staining showed that there were no evident cell destruction discovered.Conclusions PMMA-Fe3O4 was an excellent magnetic material for the localized magnetic hyperthermia ablation of tumors. |
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