Abstract

Mesoporous silica MCM-41 was prepared and decorated by polyethyleneimine (PEI) with different molecule weight before loading tea tree oil (TTO) to construct an environment-friendly antimicrobial sustained release system. The characterization results proved that the PEI was successfully introduced to pores of the mesoporous silica without destruction of the structure integrity. The strength of electrostatic interaction between PEI and MCM-41 was measured by the value of zeta potential which indicated that PEI with low molecule weigh was easier to be adsorbed by MCM-41 pores due to its low viscosity. The interaction of MCM-41 with TTO was strengthened after PEI modification. As a result, TTO/PEI600-MCM-41 performed the lowest cumulative release rate of 46.88% in 12 h due to the strongest interaction with TTO among all the samples. Kinetics study indicated that PEI constructed a new barrier for drug diffusion and volatilization through winding and swelling. The kinetic model for TTO/MCM-41 sustained release changed from first-order to Weibull model after PEI modification. What’s more, the service life of TTO in antimicrobial was also obviously prolonged after supported on mesoporous silica modified by PEI.

摘要

在负载茶树油（TTO）之前，用不同分子量的聚乙烯亚胺（PEI）制备并修饰介孔二氧化硅MCM-41，构建环保型抗菌缓释体系。表征结果证明PEI成功地引入到介孔二氧化硅的孔中而没有破坏结构完整性。PEI 与 MCM-41 之间的静电相互作用强度通过 zeta 电位值测量，表明低分子量的 PEI 由于其低粘度更容易被 MCM-41 孔吸附。PEI 改性后，MCM-41 与 TTO 的相互作用得到加强。结果，由于在所有样品中与 TTO 的相互作用最强，TTO/PEI600-MCM-41 在 12 小时内的累积释放率最低，为 46.88%。动力学研究表明，PEI通过缠绕和溶胀为药物扩散和挥发构建了新的屏障。PEI 修饰后，TTO/MCM-41 缓释动力学模型由一级变为 Weibull 模型。更重要的是，TTO在PEI改性的介孔二氧化硅上负载后在抗菌剂中的使用寿命也明显延长。