National Engineering Research Center for Nano-Medicine, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
Biomacromolecules. 2013 Apr 8;14(4):1078-84. doi: 10.1021/bm3019664. Epub 2013 Mar 21.
Dispersions of poly(N-isopropylacrylamide-co-butyl methacrylate) (PNB) nanogels are known to exhibit reversible thermosensitive sol-gel phase behavior and can consequently be used in a wide range of biomedical applications. However, some dissatisfactory mechanical properties of PNB nanogels can limit their applications. In this paper, bacterial cellulose (BC) whiskers were first prepared by sulfuric acid hydrolysis and then nanosized by high-pressure homogenization for subsequent use in the preparation of BC whisker/PNB nanogel complexes (designated as BC/PNB). The mechanical properties of PNB was successfully enhanced, resulting in good biosafety. The BC/PNB nanogel dispersions exhibited phase transitions from swollen gel to shrunken gel with increasing temperature. In addition, differential scanning calorimetry (DSC) data showed that the thermosensitivity of PNB nanogels was retained. Rheological tests also indicated that BC/PNB nanogel complexes had stronger gel strengths when compared with PNB nanogels. The concentrated dispersions showed shear thinning behavior and improved toughness, both of which can play a key role in the medical applications of nanogel complexes. Furthermore, the BC/PNB nanogel complexes were noncytotoxic according to cytotoxicity and hemolysis tests. Concentrated BC/PNB nanogel dispersion displayed gel a forming capacity in situ by catheter injection, which indicates potential for a wide range of medical applications.
聚（N-异丙基丙烯酰胺-共-甲基丙烯酸丁酯）（PNB）纳米凝胶分散体具有可逆的温敏溶胶-凝胶相转变行为，因此可以在广泛的生物医学应用中使用。然而，PNB 纳米凝胶的一些不理想的机械性能可能会限制其应用。在本文中，首先通过硫酸水解制备细菌纤维素（BC）纳米纤维，然后通过高压匀浆使其纳米化，用于制备 BC 纳米纤维/PNB 纳米凝胶复合物（命名为 BC/PNB）。成功增强了 PNB 的机械性能，同时保持了良好的生物安全性。BC/PNB 纳米凝胶分散体表现出随温度升高从溶胀凝胶到收缩凝胶的相转变。此外，差示扫描量热法（DSC）数据表明 PNB 纳米凝胶的温敏性得以保留。流变学测试也表明，与 PNB 纳米凝胶相比，BC/PNB 纳米凝胶复合物具有更强的凝胶强度。高浓度分散体表现出剪切稀化行为和提高的韧性，这两者都可以在纳米凝胶复合物的医疗应用中发挥关键作用。此外，根据细胞毒性和溶血试验，BC/PNB 纳米凝胶复合物无细胞毒性。高浓度的 BC/PNB 纳米凝胶分散体通过导管注射原位形成凝胶，这表明其在广泛的医疗应用中具有潜力。
