Preparation of pH-Responsive Doxorubicin Nanocapsules by Combining High-gravity Antisolvent Precipitation with In-situ Polymerization for Intracellular Anticancer Drug Delivery

Owing to the low pH value in tumor and cancer cells, drug delivery systems based on pH-responsive polymer nanocarriers have been extensively explored for anticancer chemotherapy. Herein, we developed a pH-responsive doxorubicin(DOX) nanocapsule(named as DNanoCapsule) prepared by combining in-situ polymerization technique with high-gravity antisolvent precipitation technique through an amphiphilic polymerized surface ligand. DNanoCapsules show an obvious spherical core-shell structure with a single DOX nanoparticle encapsulated in the polymer layer. Dissolution rate studies prove that the DNanoCapsules have robust drug-release profiles under acidic environments due to the division of the pH-sensitive cross-linker, which triggers the collapse of the polymer layer. The in vitro investigations demonstrated that the DNanoCapsules exhibited high cellular uptake efficiency and cytotoxicity for both HeLa and MCF-7 cancer cells. Therefore, this work may provide a promising strategy to design and develop various stimuli-responsive drug nanocapsules for the treatment of cancer or other diseases.     

纳米尺度超声显影微囊的制备及性能表征简

采用双乳液-溶剂挥发法制备了内部包封氟碳液体的聚乳酸-甲氧基聚乙二醇两嵌段共聚物(MePEG-b-PLA)基超声显影纳米微囊;用2种不同嵌段比的MePEG-b-PLA共聚物研究共聚物组成与纳米囊性能的关系;选用聚乙烯醇(PVA)、羧甲基葡聚糖(CMG)和壳聚糖(CS) 3种乳化剂对纳米囊表面进行亲水性修饰. 对所制备纳米囊的粒径、Zeta电位、形貌和水溶液稳定性进行了表征. 结果表明,利用质量分数为1%的PVA和质量分数为1%的CMG组成的复配乳化剂和m(MePEG)：m(PLA)= 1：3的聚合物制得的纳米囊的平均粒径为432.9 nm,水溶液稳定性优良. 利用超声仪对纳米囊体外超声显影性能进行研究,结果表明,所得聚乳酸-甲氧基聚乙二醇纳米囊具有更好的中心成像区域灰度值和更持久的体外超声显影效果. 结合3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)比色法研究证实该纳米囊具有低细胞毒性. 在超声影像学领域具有良好的应用前景.     

PLA/PEG/PLA三嵌段共聚物载药纳米胶囊的制备及表征

用于药物控释体系的微胶束具有实心微球结构,药物分子主要吸附于微球表面,极易脱落,在释药初期有明显的突释效应;而微胶囊的药物主要集中于囊心部分,药物通过扩散作用以及高分子膜的降解而逐渐释放到环境中,因而更有利于药物分子平稳、缓慢地释放．对于自然界中能够自发形成微胶囊的小分子材料,其分子中往往具有一个较小的亲水部分和一个相对较大的憎水部分,     

界面聚合法制备聚α-氰基丙烯酸正丁酯毫微囊

采用界面聚合法制备了粒径约 2 0 0nm的聚α 氰基丙烯酸正丁酯毫微囊 ,运用动态激光光散射和透射电镜测定了毫微囊的粒径及其分布 ,系统研究了高分子稳定剂类型、表面活性剂的用量、辅助添加剂的用量、以及后处理条件等因素对毫微囊粒径及其分布的影响 .结果说明 ,在高分子稳定剂中 ,葡聚糖的稳定作用优于Poloxamer 188,而葡聚糖的用量越大 ,毫微囊的粒径越小 ,采用葡聚糖 70比葡聚糖 40更能得到窄分布的毫微囊 .增加表面活性剂吐温 2 0的用量 ,同样减小毫微囊的粒径 .与三油酸甘油酯相比 ,在有机相中加入苯甲醇能够增大毫微囊粒径 ,并改善毫微囊的规整性 .乙醇和丙酮均可作为溶剂添加在有机相中 ,但含乙醇的体系分散较好 ,界面聚合得到聚α 氰基丙烯酸正丁酯毫微囊粒径分布较窄 .此外 ,通过考察浓缩温度发现 ,在2 0℃下真空浓缩时毫微囊粒径基本保持不变 ,而在 30℃下则发生一定程度的毫微囊聚集     

有无N-异丙基丙烯酰胺制备纳米微胶囊机理的比较

通过研究交联剂对颗粒形态的影响, 提出小分子烃的逃逸是导致生成大量小尺寸实心粒子的主要原因, 而交联剂的加入在一定程度上能抑制小分子烃的逃逸. 将N-异丙基丙烯酰胺单体引入小分子烃为模板的细乳液聚合法制备的纳米微胶囊体系中, 水相引发形成的聚N-异丙基丙烯酰胺(PNIPA)齐聚物自由基在聚合温度下(大于最低临界溶液温度)析出并被细乳液液滴吸附, 在热力学推动力和静电斥力的共同作用下, PNIPA齐聚物倾向于分布在液滴和水的界面上, 使液滴界面成为主要的聚合场所, 单体从液滴内部向界面扩散补充消耗的单体, 生成的聚合物在液滴界面上析出, 包覆小分子烃液滴, 最终得到纳米微胶囊.     

纳米尺度超声显影微囊的制备及性能表征

采用双乳液-溶剂挥发法制备了内部包封氟碳液体的聚乳酸-甲氧基聚乙二醇两嵌段共聚物(MePEG-b-PLA)基超声显影纳米微囊; 用2种不同嵌段比的MePEG-b-PLA共聚物研究共聚物组成与纳米囊性能的关系; 选用聚乙烯醇(PVA)、 羧甲基葡聚糖(CMG)和壳聚糖(CS) 3种乳化剂对纳米囊表面进行亲水性修饰. 对所制备纳米囊的粒径、 Zeta电位、 形貌和水溶液稳定性进行了表征. 结果表明, 利用质量分数为1%的PVA和质量分数为1%的CMG组成的复配乳化剂和m(MePEG)∶m(PLA)= 1∶3的聚合物制得的纳米囊的平均粒径为432.9 nm, 水溶液稳定性优良. 利用超声仪对纳米囊体外超声显影性能进行研究, 结果表明, 所得聚乳酸-甲氧基聚乙二醇纳米囊具有更好的中心成像区域灰度值和更持久的体外超声显影效果. 结合3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)比色法研究证实该纳米囊具有低细胞毒性. 在超声影像学领域具有良好的应用前景.     

Preparation of protected photoinitiator nanodepots by the miniemulsion process

The solid photoinitiator Lucirin TPO was encapsulated within a polymer shell by using the miniemulsion process. A solution of Lucirin TPO in methyl methacrylate (MMA) or butyl acrylate (BA)/MMA mixture was miniemulsified in water followed by a polymerization process in which phase separation of the Lucirin TPO and the formed polymer led to amorphously solidified Lucirin TPO nanoparticles encapsulated by polymer. These nanocapsules were freeze-dried and could be redispersed in acidic monomers, which are applied in polymeric dental adhesives. It is shown by ¹H nuclear magnetic resonance spectroscopy that the shell separates the Lucirin TPO, which is sensitive to degradation in acidic media, from an ambient acidic monomer phase and protects it from fast decomposition. Investigations of the release kinetics of Lucirin TPO from the nanocapsules reveal that the kinetics are strongly dependent on the composition of the surrounding continuous phase.     

A personal journey on using polymerization in aqueous dispersed media to synthesize polymers with branched structures

Several projects were discussed to demonstrate the intriguing power of radical polymerization in aqueous dispersed media to regulate the branched structures in functional polymeric nanomaterials.