聚乙二醇修饰的可控温磁性纳米颗粒制备与表征研究

Synthesis and characterization of polyethylene glycol-coated self-regulated magnetic nanoparticles

目的磁性纳米颗粒(MNPs)是当前重要的肿瘤诊断与治疗载体平台,可在交变磁场作用下产生热效应,从而杀死肿瘤细胞。调节MNPs的居里温度,可提高其在肿瘤磁感应热疗中的安全性。方法用水热法合成可控温的Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4),用相对分子质量为20000的聚乙二醇(PEG)修饰包被。用透射电子显微镜(TEM)观测MNPs的大小、形貌、分散性等,X射线衍射仪(XRD)表征其晶体结构,振动样品磁强仪(VSM)测试磁性特性。用CCK-8检测修饰和未修饰的MNPs对正常人肝外胆管上皮细胞(HEBEpiC)的毒性作用。结果TEM结果显示,PEG修饰前Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)存在明显的聚集现象;PEG修饰后,Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)@PEG20000呈现基本均一的类球形态,分散性提高。XRD结果显示,MNPs含有Zn^(2+)、Co^(2+)、Cr^(3+)和Fe^(3+),并具有与CoFe_(2)O_(4)相同的特征衍射峰,表明其具有立方尖晶石结构。VSM结果表明,MNPs呈现良好的超顺磁性。细胞毒性结果表明,两组MNPs均未对HEBEpiC细胞产生显著的毒性作用。相比未修饰组,PEG修饰组的细胞活力略高于未修饰组。结论PEG修饰可以显著改善可控温MNPs Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)的分散性、磁热特性和细胞毒性。修饰后的Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)@PEG20000可用于药物递送、诊断和治疗等。

Objective To investigate magnetic nanoparticles(MNPs)as important carriers for cancer diagnosis and therapy because they can generate heat under an alternating magnetic field to kill tumor cells.Regulating the Curie temperature of MNPs can enhance their safety for magnetic hyperthermia cancer treatment.Methods Self-regulated Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)were synthesized via the hydrothermal method,and then modified by polyethylene glycol(PEG)with a molecular weight of 20000.Transmission electron microscope(TEM),X-Ray diffractometer(XRD)and vibrating sample magnetometer(VSM)were utilized to characterize the size,morphology,crystal structure and magnetic properties of MNPs.The cytotoxicity of pristine and PEG-modified MNPs toward normal human extrahepatic bile duct epithelial cells(HEBEpiC)was evaluated by the cell counting kit-8(CCK-8)assay.Results TEM results revealed a significant aggregation in unmodified Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)nanoparticles while PEG-modified Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4)@PEG20000 exhibited relatively uniform quasi-spherical morphology with improved dispersibility.XRD results revealed that MNPs possessed the characteristic diffraction peaks of the cubic spinel structure of CoFe_(2)O_(4)and contained Zn^(2+),Co^(2+),Cr^(3+),and Fe^(3+).VSM results demonstrated good superparamagnetism of MNPs.The CCK-8 assay results demonstrated that neither form of MNPs exhibited significant toxicity toward HEBEpiC cells across the tested concentration range.Compared to the MNPs group,the PEG-modified MNPs showed slightly higher cell viability of HEBEpiC,indicating the PEG helped further reduce the cytotoxicity of MNPs toward HEBEpiC cells.Conclusion This study indicates that PEG coating could significantly improve the dispersibility,magnetothermal properties and cytotoxicity of Zn_(0.54)Co_(0.46)Cr_(0.6)Fe_(1.4)O_(4),laying the foundation for their potential biomedical applications in drug delivery,diagnosis and therapy.