The preparation and characterization of folate-conjugated human serum albumin magnetic cisplatin nanoparticles

Objective： Nanoparticles are becoming an important method of targeted drug delivery. To evaluate the importance of folate-conjugated human serum albumin （HSA） magnetic nanoparticles （Folate-CDDP/HSA MNP）, we prepared drug-loaded Folate-CDDP/HSA MNPs and characterized their features. Methods： First, folate was conjugated with HSA under the effect of a condensing agent, and the conjugating rate was evaluated by a colorimetric method using 2, 4, 6 - trinitrobenzene sulfonic acid. Second, under N., gas, Fe：~O1 magnetic nanomaterials were prepared and characterized by using transmission electron microscopy （TEM）, SEM-EDS and X-ray diffraction （XRD）. Finally, Folate-CDDP/HSA MNP was prepared by using a solvent evaporation technique. TEM was used to observe particle morphology. The particle size and distribution of the prepared complexes were determined by a Laser particle size analyzer. Drug loading volume and drug release were investigated by a high performance liquid chromatography method （HPLC） in vitro. Results： We successfully prepared folate-conjugated HSA and its conjugating rate was 27.26 μg/mg. Under TEM, Fe2O4 magnetic nanoparticles were highly electron density and had an even size distribution in the range of 10-20 nm. It was confirmed by SEM-EDS and XRD that Fe304 magnetic nanoparticles had been successfully prepared. Under TEM, drug-loaded magnetic nanoparticles were observed, which had a round shape, similar uniform size and smooth surface. Their average size was 79 nm which was determined by laser scattering, and they exhibited magnetic responsiveness. Encapsulation efficiency was 89.75% and effective drug loading was calculated to be 15.25%. The release results in vitro showed that the half release time （ta/2） of cisplatin in cisplatin Solution and Folate-CDDP/HSA MNP was 65 min and 24 h respectively, which indicated that microspheres had an obvious effect of sustained-release. Conclusion： Folate-CDDP/HSA MNPs were prepared successfully. The preparation process and related characteristics data provided a foundation for further study, including the mechanism of the nanoparticles distribution in vivo and their intake by tumor cells.

叶酸偶联白蛋白纳米粒的制备工艺研究

采用去溶剂化法制备普通白蛋白纳米粒 ,利用叶酸活性酯在微碱性条件下与白蛋白纳米粒表面的氨基反应 ,制得叶酸偶联白蛋白纳米粒。采用葡聚糖凝胶柱色谱法及紫外分光光度法验证偶联是否成功 ,并测定叶酸偶联的程度。通过葡聚糖凝胶柱色谱法可以清楚地看到叶酸偶联白蛋白纳米粒与未反应的叶酸活性酯完全分离 ,叶酸偶联白蛋白纳米粒与叶酸白蛋白机械混合物的胰蛋白酶水解液在 35 8nm处的紫外吸收图谱基本一致 ,说明叶酸已经成功地偶联于白蛋白纳米粒的表面。纳米粒形态圆整 ,平均粒径为 6 6 nm。叶酸偶联白蛋白纳米粒制备成功 ,作为叶酸受体表达丰富的多种肿瘤细胞的主动靶向给药的潜在途径 。

叶酸偶联白蛋白纳米粒肿瘤细胞靶向性研究

目的 研究能通过叶酸受体介导靶向肿瘤细胞的叶酸偶联白蛋白纳米粒。方法 利用叶酸活性酯在碱性条件下与白蛋白纳米粒表面上的氨基反应 ,制得叶酸偶联的白蛋白纳米粒。以荧光定量法确定浓度、时间、游离叶酸对肿瘤细胞摄取叶酸偶联白蛋白纳米粒的影响程度。结果 成功制备了叶酸偶联白蛋白纳米粒。叶酸偶联白蛋白纳米粒的肿瘤细胞摄取量随纳米粒浓度增大、培养时间延长而增加 ,肿瘤细胞对叶酸偶联白蛋白纳米粒的摄取可被过量的外源性游离叶酸所抑制。结论 叶酸偶联白蛋白纳米粒能通过细胞膜上的叶酸受体介导内吞入胞 。

叶酸受体介导的载顺铂磁性纳米pH敏感药物的制备及性能

【目的】制备具有叶酸受体靶向、磁靶向及pH敏感释放的载顺铂磁性纳米药物(FA-PEG-NH-N=MNPs-CDDP),为进一步研发智能靶向头颈部肿瘤药物载体奠定基础。【方法】采用化学共沉淀法制备醛基化海藻酸钠改性的四氧化三铁纳米粒(MNPs),海藻酸钠表面的羧基通过配位络合作用与顺铂连接,制备的偶联叶酸的双肼基PEG,其肼基端与海藻酸钠的醛基通过腙键连接包裹载药纳米粒,经纯化获得叶酸修饰的载顺铂磁性纳米pH敏感靶向抗癌药物(FA-PEG-NH-N=MNPs-CDDP),采用紫外分光光度计、透射电镜(TEM)、振动样品磁强计(VSM)、激光动态粒径仪等对其理化性状等进行表征,同时采用细胞铁染色、透射电镜和体外实验来评估其细胞靶向性和pH敏感释药特征。【结果】该纳米药物顺铂含量为0.773 mg/mL,铁含量约为1.908 mg/mL;透射电镜下磁核平均粒径约为(10.2±1.5)nm,激光粒度仪测得平均水动力学直径(176.6±1.1)nm,zeta电位为(-20.91±1.76)mV,最大饱和磁化强度为(16.3±0.2)emu/g,能被叶酸受体阳性细胞摄取,并能在低pH值下释放药物。【结论】该磁性纳米药物具有良好的稳定性、叶酸受体靶向性和pH敏感释药功能,为肿瘤的药物靶向转运奠定了基础。

核素标记叶酸偶联白蛋白纳米微球对人卵巢癌细胞生长的影响

目的观察核素标记叶酸靶向白蛋白纳米微球对人卵巢癌细胞生长的影响。方法将体外培养的SKOV3人卵巢癌细胞分为八组:阴性对照组(只加RPMI-1640培养液),单纯化疗组(叶酸偶联载药白蛋白磁性纳米微球,不加磁场),单纯放疗组[188铼(188 Re)标记的叶酸偶联白蛋白磁性纳米微球,不加磁场],单纯热疗组(叶酸偶联白蛋白磁性纳米微球,加磁场),化疗联合放疗组(188 Re标记的叶酸偶联载药白蛋白磁性纳米微球,不加磁场),化疗联合热疗组(叶酸偶联载药白蛋白磁性纳米微球,加磁场),放疗联合热疗组(188 Re标记的叶酸偶联白蛋白磁性纳米微球,加磁场)和热疗、化疗、放疗联合治疗组(联合治疗组,188 Re标记的叶酸偶联载药白蛋白磁性纳米微球,加磁场)。48h后MTT方法测定各组细胞增殖率,流式细胞术测定细胞凋亡率。结果阴性对照组对卵巢癌细胞增殖的抑制作用弱于其他各组,联合治疗组强于其他各组(P<0.05)。单纯热疗组、化疗联合放疗组、化疗联合热疗组、放疗联合热疗组和联合治疗组中细胞周期G1期前出现明显的亚二倍体凋亡峰;阴性对照组、单纯热疗组、化疗联合放疗组、化疗联合热疗组、放疗联合热疗组和联合治疗组的细胞凋亡率分别为0.08%、7.56%、17.14%、21.64%、33.94%和57.16%。结论磁感应热疗、化疗、核素靶向放疗的联合作用能有效抑制人卵巢癌细胞的生长。