Hollow mesoporous silica nanoparticles

Mei, X. Yang, S. Chen, D. Li, N. Li, H. Xu, Q. Ge, J. Lu, J. Light-triggered reversible assemblies of azobenzene-containing amphiphilic copolymer witb beta-cyclodexlrin-modifled hollow mesoporous silica nanoparticles for controlled drug release. Chem. Commun. 2012, 48, 10010-100102. 

Figure 11.6 (a) A scheme for the preparation of hollow mesoporous silica nanoparticles by removal of surfactant and iron oxide templates upon trimethylsilylation under acidic conditions. (b) TEM images of the hollow mesoporous silica nanoparticles [39]. 

The potential of hollow mesoporous silica nanoparticles as a drug carrier has been actively researched in vitro. For example, hollow mesoporous silica nanospheres with uniform sizes of 31-33 nm, prepared using PS-PVP-PEO triblock copolymer micelles, exhibited a higher storage capacity of a model drug (ibupro-fen) than the conventional mesoporous silica particles [111]. A more sustained release was achieved by propylamine functionalization, which is effective for controlled release of drug molecules. 

Ikuno, T., Nomura, A., lyoki, K., Sugawara-Namtaki, A., Okubo, T., and Shimojima, A. (2013) Facile synthesis of well-dispersed hollow mesoporous silica nanoparticles using iron oxide nanoparticles as template. Chem. Lett.,... 

Chen, T., Yang, N., and Fu, J. (2013) Controlled release of cargo molecules from hollow mesoporous silica nanoparticles based on acid and base dual-responsive cucurbit[7]uril pseudorotaxanes. Chem. Commun.,... 

In this chapter, we provide an overview of the recent research and development in the preparation, characterization, and application of novel porous carbons using both the endotemplate and the exotemplate methods. A discussion of zeolite templates for microporous carbons is followed by that of ordered mesoporous silica templates for OMCs, nanoparticle templates for mesoporous carbons, sol-gel processed porous carbons, self-assembled colloidal crystal templates for ordered macroporous carbons, and colloidal sphere templates for hollow carbon spheres, as well as other templating approaches to preparing carbon nanostructures. Then,... 

The product obtained under acid conditions was an ellipsoid nanoparticle, and that obtained under alkaline condition was hollow silica ensembles. The study revealed that [bmimJBF played a critical role in the process of formation of the mesoporous silica hollow structure. It was thus evident that nonaqueous IL microemulsions can contribute to the synthesis of materials with various structures by providing a reaction environment that is able to control the size and morphology of the materials. 

Elsewhere, various other hollow mesoporous nanosilica have also been explored for their medical applications. Zhou et al. discussed the use of hollow silica nanospheres with magnetic nanoparticles (e.g. Fe304) within the pores to deliver ibu-profen. When the drug had been stored inside the pores, the openings were encapsulated [17]. As a consequence, the size of the nanospheres was of the order of a few hundred nanometers, while the magnetic Fe304 nanoparticles were about 5-10 nm. It should be noted here that these nanomaterials were used exclusively for delivery purposes. 

Recently, hollow silica nanoparticles with mesoporous shells have attracted much attention for the capabihty of molecules to interdifftise through the shells and for their enhanced surface area and porosity, which give the particles an increased drug storage capacity and lower refractive index. 

FIGURE 12.6 (a) Illustration of the preparation of mesoporous Au-mesoporous carbon and silica capsules using glucose as carbon source. (From Kim, J. Y. et al., Chemical Communications, 790, 2003.) (b) TEM images of Au nanoparticles in microporous carbon hollow spheres prepared from dopamine as the carbon precursor. The carbon spheres were as large as the Au-silica template spheres, approximately 400 nm in diameter, and the carbon walls were A nm thick. (From Liu, R. et al., Angewandte Chemie-Intemational Edition, 50, 6799, 2011.)... 

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