A New Type Of Magnetic Bone Cement Preparation And Its Biocompatibility In Vitro Cell Research

Objective:In this study, we attempt to add magnetic nanoparticles to bone repair materials and develop a new kind of magnetic bone cement, this novel magnetic bone repair material not only can repair bone defect, also can generate enough heat under alternate magnetic field to kill the bone tutor by hyperthennia. We investigated the characterization of the magnetic composite bone repair material and tested cytotoxicity in vitro to research whether it can be used to as a novel magnetic bone material for bone tumor.Methods:1. Preparation of magnetic nanoparticles:the magnetic nanoparticles were prepared by chemical coprecipitation and modified by amino silane. Then, the magnetic nanoparticles were characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and X-ray diffiactometer(XRD).2. Preparation and characterization of magnetic calcium phosphate bone cement (CPC):Different amount of magnetic nanoparticles were added to clinical CPC. Different magnetic ion concentration of composite bone repair material was prepared. Then, we investigate the compressive strength, setting time, peak temperature, vitro heat generation of this novel bone material.3. Preparation and characterization of Polymethylmethacrylate (PMMA) bone repair material: according to the ISO5833standard, different amount of magnetic nanoparticles were added to Polymethylmethacrylate. Then, we developed a novel PMMA-based magnetic bone materials and the compressive strength, setting time, peak temperature, vitro heat generation of this novel bone cement was characterized.4. A preliminary inquiry of cytotoxicity of magnetic composite bone repair materials in vitro: According to ISO2009-10993.12"Biological evaluation standard of medical devices part12: sample preparation and reference samples" Cell-mediated cytotoxicity of magnetic bone cement leaching solution to L929fibroblasts was tested by method CCK-8. For24h,48h,72h of testing time points, we sized material toxicity according to relative growth rate.Results:1. magnetic nanoparticle Diameter of a single nanometer magnetic particles is about20-35run. Average particle size of aggregation state is180nm-220nm. Aminosilane covering amount on surface is3%-6%.The magnetic nanoparticle has superparamagnetism and has a good capability of heat Under the alternating magnetic field. 2. Magnetic CPC material: Magnetic composite bone repair material has good performance in compressive strength, setting time, melting resistance and can be used for bone hypothermia3. Magnetic PMMA material: magnetic composite bone repair material has good performance in compressive strength, setting time, melting resistance. It shows that the material has good heating effect which means the good killing function on bone tumors.4. Experiments of magnetic composite bone repair material in vitro: magnetic poly methyl acrylic resin showed mild toxicity. Magnetic calcium phosphate bone repair material showed good biocompatibility and no cytotoxicity.Conclusion:The general perfomiance of magnetic bone repair materials conform to the ISO5833standard. The material can kill the tumor cells by raising the temperature of magnetic induction. Magnetic calcium phosphate bone repair material has good biocompatibility. And it was expected to become a new functional material of the bone tumor treatment.