| Hyperthermia technology has become a new type of tumor therapy due to its advantages such as small side effects.In view of the characteristics of tumor cells for fear of heat, one important step of hyperthermia technology under the condition of alternating magnetic field and microwave field is to destroy the tumor cells which is heated to 43℃ without damaging the normal cells. Therefore, under the condition that the existing thermal seed material is difficult to be controlled automatically, it has very important significance to study the thermal seed material with high thermal efficiency, stable control of heating temperature, good stability and good biocompatibility. Due to the unique properties of carbon nanotubes and graphene, the purpose of this study is to design a completely new graphene(carbon nanotubes)/ferrites temperature controlled composite materials which have excellent thermal performance, good biocompatibility and reliable temperature control effect. The main research results are as follows.Owing to its good chemical stability and high biological compatibility, LiZn ferrites are considered to be a promising application in hyperthermia therapy. Due to the good thermal diffusivity of carbon nanotubes, and large theoretical surface area of graphene, this paper is to prepare CNTs/LiZn ferrites and graphene/LiZn ferrites by sol-gel method combined with subsequent calcination treatment. In this study, composites with different content of carbon nanotubes/graphene were prepared, and the properties of the composites were analyzed by using XRD, TEM, SEM and VSM.The temperature change of CNTs/Lio 25Zn0.5Fe2.25O4 in alternating magnetic field is between the LiZn ferrites and carbon nanotubes. The thermal production mechanism of magnetic nanoparticles in the alternating magnetic field include Hysteresis loss, Neel relaxation and friction. The addition of carbon nanotubes has an influence on the spin of magnetic nanoparticles and the movement of domain wall. When the content of carbon nanotubes is 1%and 3%, the reliable temperature-control temperature is (40.8℃ and 53℃) to meet the temperature which is required in magnetic hyperthermia. In the microwave field (Its frequency is 2.45 GHz), the wave absorbing mechanism of LiZn ferrites is natural resonance, and less friction loss of polar molecules lend to low thermal production in this range; Carbon nanotubes produce multiple scattering in this condition and it exacerbate the motion of atoms and electrons, thus the thermal effect is obvious. When the carbon nanotube content is 1%,3%,5%,7% and 9%, the temperature variation of composites is 6.4℃,7.3℃,9.7℃,7.6℃,5.7℃ respectively, and the thermal effect is small.In an alternating magnetic field, the temperature variation of GE ZLi0.45Zn0.1Fe2.45O4 has a positive corresponding relationship with the specific saturation magnetization. When the content of graphene is 1%,3%,5%,7% and 9%, the temperature variation of composite is 68.2℃,25℃,17.3℃,13.3℃ and 12.5℃. Due to the high temperature of animal body, the temperature of tumor tissue can achieve the standard and no damage to normal tissue under ΔT. When the content of graphene is 3%, the balance temperature is 44.6℃ and it meet the temperature required of tumor hyperthermia for 40℃-60℃. In microwave field, the temperature change Δ T of composites with different graphene are about 4℃, and the thermal effect is small.In summary, CNTs/LiZn ferrites and Graphene/LiZn ferrites have the very considerable thermal effect and the temperature control performance in an alternating magnetic field and a microwave field,and it is expected to show a good application value in the field of tumor therapy. |
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