Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, Nankai University, Tianjin, 300071, PR China.
Langmuir. 2010 Dec 7;26(23):18503-7. doi: 10.1021/la103629v. Epub 2010 Nov 9.
The silica/polymer hybrid hollow nanoparticles with channels and gatekeepers were successfully fabricated with a facile strategy by using thermoresponsive complex micelles of poly(ethylene glycol)-b-poly(N-isopropylacrylamide) (PEG-b-PNIPAM) and poly(N-isopropylacrylamide)-b-poly(4-vinylpyridine) (PNIPAM-b-P4VP) as the template. In aqueous solution, the complex micelles (PEG-b-PNIPAM/PNIPAM-b-P4VP) formed with the PNIPAM block as the core and the PEG/P4VP blocks as the mixed shell at 45 °C and pH 4.0. After shell cross-linking by 1,2-bis(2-iodoethoxyl)ethane (BIEE), tetraethylorthosilicate (TEOS) selectively well-deposited on the P4VP block and processed the sol-gel reaction. When the temperature was decreased to 4 °C, the PNIPAM block became swollen and further soluble, and the PEG-b-PNIPAM block copolymer escaped from the hybrid nanoparticles as a result of swelled PNIPAM and weak interaction between PEG and silica at pH 4.0. Therefore, the hybrid hollow silica nanoparticles with inner thermoresponsive PNIPAM as gatekeepers and channels in the silica shell were successfully obtained, which could be used for switchable controlled drug release. In the system, the complex micelles, as a template, could avoid the formation of larger aggregates during the preparation of the hybrid hollow silica nanoparticles. The thermoresponsive core (PNIPAM) could conveniently control the hollow space through the stimuli-responsive phase transition instead of calcination or chemical etching. In the meantime, the channel in the hybrid silica shell could be achieved because of the escape of PEG chains from the hybrid nanoparticles.
具有通道和门禁的硅/聚合物杂化中空纳米粒子采用简便的策略成功制备，该策略使用聚（乙二醇）-b-聚（N-异丙基丙烯酰胺）（PEG-b-PNIPAM）和聚（N-异丙基丙烯酰胺）-b-聚（4-乙烯基吡啶）（PNIPAM-b-P4VP）的温敏复合胶束作为模板。在水溶液中，复合胶束（PEG-b-PNIPAM/PNIPAM-b-P4VP）在 45°C 和 pH 4.0 下形成，PNIPAM 嵌段作为核，PEG/P4VP 嵌段作为混合壳。在 1,2-双（2-碘乙氧基）乙烷（BIEE）进行壳交联后，正硅酸乙酯（TEOS）选择性地沉积在 P4VP 嵌段上并进行溶胶-凝胶反应。当温度降低到 4°C 时，PNIPAM 嵌段溶胀并进一步溶解，PEG-b-PNIPAM 嵌段共聚物由于 pH 4.0 下溶胀的 PNIPAM 和 PEG 与二氧化硅之间的弱相互作用而从杂化纳米粒子中逃逸。因此，成功获得了具有内部温敏 PNIPAM 作为门控和二氧化硅壳中的通道的杂化中空硅纳米粒子，可用于开关控制药物释放。在该体系中，复合胶束作为模板，可在制备杂化中空硅纳米粒子期间避免形成较大的聚集体。温敏核（PNIPAM）可通过刺激响应的相转变方便地控制中空空间，而无需煅烧或化学刻蚀。同时，由于 PEG 链从杂化纳米粒子中逃逸，杂化二氧化硅壳中的通道得以实现。
