The Preparation Of Hollow Mesoporous Silica Nanospheres Templated By Gemini Surfactants And Their Drug Loading Properties

Mesoporous silica nanoparticles (MSNs) have lots of excellent features such as tailored ordered mesoporous channel, high surface area and pore volume, silanol-containing surface for further surface modification, chemical inertness and good biocompatibility, which almost meet the all demands of ideal carrier. Hollow mesoporous silica nanoparticles (HMSNs) pose unique hollow interior cavities and penetrative mesoporous silica shells. Compared with conventional solid MSNs, HMSNs exhibit low density and high loading capacity and more advantages in mass diffusion and transportation, which show potential applications in catalysis, separation, confined synthesis, energy storage and drug delivery, etc.At present, HMSNs have been prepared mainly by double templates and selective etching methods. However, these methods have some disadvantages, such as complicated synthesis processes, poor dispersity, nonuniform particles, residual of strong corrosive reagents, which greatly limit the application of HMSNs furthermore. As a template, the structure of surfactants dramatically affects the micellization of surfactants and the resulting mesophase. Compared with conventional single chain surfactants, gemini surfactants have some advantages, such as adjustable structure, low critical micelle concentration and versatile aggregation morphologies. Here, some mesoporous silica materials have been developed with the templates of gemini surfactants. The main results are as follows:(1) Some quaternary ammonium gemini surfactants with simple structure were synthesized. HMSNs were prepared by an easy method of kinetic self-assembly templates of gemini surfactant(C14-2-14). Controlling the kinetic self-assembly process of gemini surfactant in reaction solution, HMSNs can be prepared successfully using only one surfactant, one silica source tetraethyl orthosilicate in one solvent.(2) A series of mesoporous silica materials were synthesized templated by gemini surfactants with different structures. The results showed that, with the increase of one of alky chains, the asymmetry of gemini surfactants decrease, and the mesophases of surfactant micelles transforms form3D cylinder to spherical, and to lamellar. As a result, the as-synthesized MSNs exhibit corresponding morphologies and structures. Anticancer drug Doxorubicin can be effectively loaded to these MSNs and be released in a diffusion-based pH-responsive fashion. HMSNs can load drug molecule more efficiently.(3) The light-controlled HMSNs were synthesized by co-condensation of tetraethoxysilane and azobenzene-functional organosiloxanes. The Rhodamine B loading and release behavior from HMSNs were investigated under UV/Vis light irradiation. The result showed that the drug release rates can be more quick when HMSNs were irradiated by UV-light and visible light alternately than that by visible light alone.(4) Hollow mesoporous silica nanoparticles (HMSNs) with the diameter in range of100-500nm and the wall thickness of about50nm were synthesized by templates of cetyltrimethylammonium bromide (CTAB) with microfluidization technique. These HMSNs were demonstrated effective drug loading and pH-responsive drug release.Our work make some explore in the preparation and structure control of HMSNs, and these material show potential in biomedicine and other fields.