窄粒径分布磁性纳米凝胶的光化学制备和表征

Modified magnetic nanoparticles have gained considerable attention because of their great potential applications in biomedical fields, such as protein and enzyme immobilization, bioseparation, immunoassays and biosensor etc. In recent years, great efforts have been made in developing targeted drug carriers by use of magnetic nauogels.Magnetic nanogels of common interest are ferromagnetic magnetite (Fe3O4) coated with cross-linked polymer nanogels. Several methods have been developed to prepare magnetic micro- and nanogels, such as inverse microemulsion polymerization, emulsion polymerization and other methods. In this paper, we propose an alternative approach to synthesize poly (N-isopropylacrylamide) (PNIPAM), polyacrylamide (PAM) superparamagnetic nauogels via photochemical reactions at room temperatures in au emulsion- and initiator-free aqueous system.Temperature-dependent magnetic nanogels weresynthesized by using NIPAM as monomer[1]. The PNIPAM-modified magnetic nauogels have the character of lower critical solution temperature (LCST),and its particle size is sensitive to environmental temperature. Polydispersity index of the magnetic nauogels modified with PNPAM are lower than 0.25(Fig. 1). The magnetic nauogels modified with PAM were prepared by using acrylamide (AM) as monomer.After Hoffinann elimination, nanogels with amino groups were also obtained[2]. Particle size of all the nauogels can be controlled by controlling the reaction time, the monomer concentration and the cross-linker concentration.High zeta potential of the magnetic nauogels were measured by PCS, and their core-shell structure and regular morphology were confirmed by TEM, AFM and SEM, respectively. The nauogels with amino groups were covalently radiolabeled with 188Re complex in vitro.In conclusion, a new approach to produce magnetic nanogels via photochemical reaction has been developed.Narrow size distribution magnetic nanogels with temperature-sensitive shell and amino groups have been synthesized successfully. This suggests promising potential applications for targeted drug carriers.     

聚丙烯酰胺包覆磁性纳米凝胶的光化学法制备及其机理研究

以丙烯酰胺为单体，N，N’-亚甲基双丙烯酰胺为交联剂，采用光化学方法在水溶液体系中制备了聚丙烯酰胺（Polyacrylamide，PAM）包覆的磁性纳米凝胶，用傅立叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR），光子相关光谱（Photo correlation spectroscopy,PCS）和电子自旋共振（Electron spin resonance，ESR）波谱对聚丙烯酰胺磁性纳米凝胶进行了表征。研究了磁性纳米凝胶粒径随反应时间、单体浓度、交联剂浓度的变化规律，并探索了聚丙烯酰胺磁性纳米凝胶的包覆机理。     

水溶液体系中光化学可控合成核壳结构磁性纳米凝胶

通过光化学方法合成并经进一步的Hoffmann降解获得了壳层带有伯胺基核壳结构磁性纳米凝胶,该磁性纳米凝胶粒径分布窄且粒径可控。由于磁性纳米凝胶的壳层水凝胶具有很好的亲水性和生物相容性,且反应过程中不加入任何表面活性剂,为该磁性纳米凝胶的生物应用奠定了良好的基础。通过光化学方法合成窄粒径分布且粒径可控的磁性纳米凝胶就我们认识而言尚未见到文献报道,有望为磁性纳米凝胶的合成提供一种新的方法。我们对合成的磁性纳米凝胶分别用傅立叶变换红外光谱（FTIR）、光子相关光谱（PCS）、原子力显微镜（AFM）和透射电子显微镜（TEM）进行了表征。     

188Re标记抗CEA单克隆抗体及荷瘤裸鼠治疗实验研究

为建立18 8Re标记抗癌胚抗原 (CEA)单克隆抗体 (McAb )C50 的直接标记方法 ,探讨其标记条件 ,用抗坏血酸还原McAb ,并以葡萄糖酸钠为中间螯合剂 ,以氯化亚锡作还原剂 ,用188Re标记C50 。观察188Re标记McAb的体外稳定性 ,探讨还原剂SnCl2 浓度、螯合剂葡萄糖酸钠浓度、抗体浓度、加入抗体间隔的时间对标记物放化纯度的影响。SPECT显像观察荷瘤裸鼠瘤内注射188Re-C50 后放射性分布 ,对治疗后的瘤体行病理观察。实验结果显示 ,188Re标记C50 的合适条件为 :2 .2— 4 .0g/LSnCl2 、0 .3mol/L葡萄糖酸钠溶液、2 .5× 10 5— 5 .0× 10 5mol/LMcAb ,反应 2h后放化纯度可达 90 %。荷瘤裸鼠瘤内注射188Re -C50 后 ,放射性集中在瘤内 ,2周后瘤体明显缩小 ,镜下观察到肿瘤细胞破裂 ,坏死。