São Carlos Institute of Physics, University of São Paulo (USP) - PO Box 369, CEP 13566-590, São Carlos, São Paulo, Brazil.
Nanoscale. 2018 Jan 25;10(4):1704-1715. doi: 10.1039/c7nr08464a.
In this study, we show the synthesis of novel hybrid organic-inorganic aerogel materials with one-dimensionally aligned pores and demonstrate their use as sustained and prolonged release systems for a hydrophobic drug. The materials are synthesized by trapping mesoporous silica nanoparticles within a hyperbranched polymer network made from poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA). The synthetic method involves dispersing mesoporous silica nanoparticles in a polymer solution, then freeze-drying the solution, and finally subjecting the resulting materials to high temperature to activate a solid-state condensation reaction between PVA and PAA. Before trapping the mesoporous silica nanoparticles within the hyperbranched polymeric network, their pores are decorated with hydrophobic groups so that they can serve as good host materials for hydrophobic drugs. The potential application of the hybrid aerogels as drug carriers is demonstrated using the hydrophobic, anti-inflammatory agent dexamethasone (DEX) as a model drug. Due to their hydrophobic pores, the hybrid aerogels show excellent drug loading capacity for DEX, with an encapsulation efficiency higher than 75%. Furthermore, the release pattern of the payloads of DEX encapsulated in the aerogels is highly tailorable (i.e., it can be made faster or slower, as needed) simply by varying the PVA-to-PAA weight ratio in the precursors, and thus the 3-dimensional (3-D) structures of the cross-linked polymers in them. The materials also show sustained drug release, for over 50 days or more. In addition, the aerogels are biocompatible, as demonstrated with Vero cells, and greatly promote the cell proliferation of L929 fibroblasts. Also, the nanoparticles functionalized with quaternary groups and dispersed within the aerogels display bactericidal activity against E. coli, S. aureus, B. subtilis, and P. aeruginosa. These new hybrid aerogels can, thus, be highly appealing biomaterials for sustained and prolonged drug release, such as wound dressing systems.
在这项研究中，我们展示了具有一维排列孔的新型杂化有机-无机气凝胶材料的合成，并展示了它们作为疏水性药物的持续和延长释放系统的用途。这些材料是通过将介孔硅纳米粒子捕获在由聚乙烯醇（PVA）和聚丙烯酸（PAA）制成的超支化聚合物网络中而合成的。合成方法包括将介孔硅纳米粒子分散在聚合物溶液中，然后冷冻干燥溶液，最后将所得材料进行高温处理以激活 PVA 和 PAA 之间的固态缩合反应。在将介孔硅纳米粒子捕获在超支化聚合物网络中之前，先对其孔进行疏水性基团修饰，以便它们可以作为疏水性药物的良好主体材料。使用疏水性抗炎剂地塞米松（DEX）作为模型药物，证明了杂化气凝胶作为药物载体的潜在应用。由于其疏水性孔，杂化气凝胶对 DEX 具有出色的药物负载能力，包封效率高于 75％。此外，通过改变前体中 PVA 与 PAA 的重量比，即可以根据需要使封装在气凝胶中的 DEX 的有效载荷的释放模式更快或更慢，从而调节交联聚合物的 3 维（3-D）结构。这些材料还显示出持续的药物释放，超过 50 天或更长时间。此外，气凝胶具有生物相容性，如通过 Vero 细胞证明的，并且极大地促进了 L929 成纤维细胞的增殖。此外，功能化有季铵基团的纳米粒子并分散在气凝胶中对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和铜绿假单胞菌具有杀菌活性。因此，这些新型杂化气凝胶可以作为用于持续和延长药物释放的有吸引力的生物材料，例如伤口敷料系统。
