Preparation Of Hollow Mesoporous Silica Nanoparticles And Their Application In Drug Delivery

Recently, hollow structures are highly attractive in both fundamental research and practical applications. In the past decades, hollow structured nanomaterials with tailored physical and chemical properties have been widely applied in catalysis, controlled release, confined synthesis, optics and electronics, energy storage, and environmental protection. Among hollow structured nanomaterials, silica is fascinating owing to its outstanding properties, such as excellent mechanical and thermal stability, easy modification, low toxicity and high biocompatibility. Up to now, many synthetic procedures have been exploited to prepare HMSNs, such as template method, self-assembly method and so on. However, exploring the simple and efficient methods for preparation of HMSNs with high specific areas and excellent performances still remains a great challenge. Based on the previous research, we explored several synthetic procedures to prepare HMSNs with different structure and morphology.In the first part, we present a facile route for rapid synthesis of hollow mesoporous silica nanoparticles by using TEA as alkali source, TEOS as silicon source, and TTAB as surfactant. According to the experimental results, TTAB and TEA play a critical role for the formation of HMSNs. SEM, TEM and BET results show that the obtained HMSNs possess spherical morphology(average diameter was about 350 nm), mesoporous channels(2.3 nm) and high specific surface areas(1355 m2g-1). A possible formation mechanism of HMSNs was proposed combined with various techniques. Moreover, the ability of HMSNs as the drug carrier was evaluated by selecting doxorubicin hydrochloride(DOX) as the model drug. The results show that the products obtained exhibited high loading capacity, 92.3 % of the DOX can be loaded into the HMSNs; and p H-responsive controlled release behavior for DOX, more than 70 wt.%(p H = 3.0) of DOX was released. This is due to their porous structures and high surface areas.In the second part, we present a facile dual-templating route for synthesis of hollow mesoporous silica nanoparticles by using carbon nanospheres as the sacrificial template and CTAB as the soft template. SEM/TEM and BET results demonstrate that the obtained HMSNs possess uniform morphology(average diameter was about 350 nm), rough surface, porous shell(pore size was about 3 to 4 nm), and good dispersion. More importantly, the formation of hollow nanostructure and mesoporous shell can be accomplished simultaneously by a simple thermal treatment process. Cell toxicity tests reveal the good biocompatibility of HMSNs. Furthermore, the HMSNs exhibit relatively high drug loading, 92.3 % of the DOX can be loaded into the HMSNs; and protein adsorption capacity, the maximum adsorption of Cyt c amounts to 0.26 g/g(21.1 μmol/g) at p H 9.6; as well as controlled p H-responsive release behavior, more than 90 wt.%(p H = 3.0) of DOX could be released.In the third part, we explored the preparation method of large-pore Si O2 nanoparticles. We investigated the influence of different experimental conditions, such as etching agent, reaction concentration and so on. The experiment results show that basic strength of etching agent plays a key role in the progress of etching. The method has more potential application in preparation of large-pore Si O2 nanoparticles.Through above research, we have a further knowledge and understanding of the process of template-free and template synthesis of HMSNs, the influence factors, formation mechanism, biocompatibility and drug release etc, and have a clear direction in future studies.