School of Pharmacy , Guangdong Pharmaceutical University , Guangzhou 510006 , China.
ACS Appl Mater Interfaces. 2018 Jun 13;10(23):20073-20084. doi: 10.1021/acsami.8b02040. Epub 2018 Jun 1.
N-doped mesoporous carbon nanospheres (NMCNs) with tunable particle size, pore size, surface roughness, and inner cavity are extremely important for the future development of new carriers for nanoencapsulation, high-performance giant molecule transport, and cell uptake. However, constructing such a multifunctional material via a simple method still remains a great challenge. Herein, a controlled growth technology was developed for the first time to synthesize such NMCNs based on the initial reaction temperature (IRT) and solution polarity. In this strategy, the IRT not only can adjust the micelle aggregation to obtain NMCNs with large mesopores but also can make the F127 micelle more lyophobic to prepare hollow N-doped mesoporous carbon spheres, which is a great breakthrough. Inspiringly, by varying the solution polarity to make nonuniform growth of nanoparticles, the litchi-like rough surface of NMCNs was obtained, which could significantly improve the cell uptake performance of NMCNs. The current understanding of nucleation and growth mechanism of nanospheres was further extended and realized the development of NMCNs with large mesopores and litchi-like rough surface, which provided a new and interesting fundamental principle for the synthesis of NMCNs. The mesoporous structure of NMCNs was successfully reverse-replicated by nanocasting of tetraethylorthosilicate to obtain mesoporous silica spheres (MSNs), revealing the easy transformation between NMCNs and MSNs. Insulin as a peptide drug cannot be directly administered orally. But it can be used as oral preparation after being loaded into NMCNs, which has never been reported before. Interestingly, the results of the animal experiment showed an excellent in vivo hypoglycemic activity. This finding provides a new paradigm for the fabrication of structurally well-defined NMCNs with a great promise for drug carriers.
氮掺杂介孔碳纳米球（NMCNs）具有可调节的粒径、孔径、表面粗糙度和内腔，对于新型纳米封装载体、高性能大分子传输和细胞摄取的未来发展至关重要。然而，通过简单的方法构建这样的多功能材料仍然是一个巨大的挑战。在此，首次开发了一种控制生长技术，基于初始反应温度（IRT）和溶液极性来合成这种 NMCNs。在该策略中，IRT 不仅可以调节胶束聚集以获得具有大介孔的 NMCNs，而且可以使 F127 胶束更加疏水性，从而制备空心氮掺杂介孔碳球，这是一个重大突破。令人鼓舞的是，通过改变溶液极性使纳米颗粒不均匀生长，得到了具有荔枝状粗糙表面的 NMCNs，这显著提高了 NMCNs 的细胞摄取性能。当前对纳米球成核和生长机制的理解得到了进一步扩展，并实现了具有大介孔和荔枝状粗糙表面的 NMCNs 的开发，为 NMCNs 的合成提供了一个新的有趣的基本原理。通过正硅酸乙酯的纳米铸型成功地对 NMCNs 的介孔结构进行了反向复制，得到了介孔硅球（MSNs），揭示了 NMCNs 和 MSNs 之间的易于转化。胰岛素作为一种肽类药物不能直接口服。但是，它可以在负载到 NMCNs 后用作口服制剂，这是以前从未报道过的。有趣的是，动物实验的结果显示出优异的体内降血糖活性。这一发现为具有良好结构定义的 NMCNs 的制造提供了一个新的范例，为药物载体提供了广阔的前景。
