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Confined space synthesis is a novel method in zeolite synthesis. It involves crystallization of the zeolite inside the pore system of an inert mesoporous matrix. In this way it is possible to prepare nanosized zeolites with a controlled size distribution by proper choice of the inert matrix. Here, confined space synthesis was adopted to prepare nanosized ZSM-5, zeolite Beta, zeolite X, and zeolite A with tailored crystal size distributions using mesoporous carbon blacks as inert matrices. All zeolites were characterized by X-ray powder diffraction, transmission electron microscopy, and nitrogen adsorption/desorption prior to and after removal of the carbon matrix. ZSM-5 with Si/Al ratios of 50, 100, and infinity (silicalite-1) were synthesized with controlled average crystal sizes in the range 20-75 nm. Nanosized zeolite Beta (7-30 nm), zeolite X (22-60 nm), and zeolite A (25-37 nm) were prepared similarly. Removal of the carbon matrix by controlled combustion allows a convenient method for isolation of the pure and highly crystalline zeolites. Therefore, confined space synthesis appears to be an attractive method for preparation of zeolites with a controlled size distribution.

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Nanogels, cross-linked networks of >1 μm in size, are attractive drug-delivery systems, as they not only possess the potential advantages of nanoscale formulations, but also the attractive abilities of a hydrogel; high hydrophilicity, high loading capacity and the potential for biocompatibility and controlled release. The focus of this review is to provide an overview of the recent developments within the nanogel field, and how the chemical design of the nanogel polymer has been found to influence the properties of the nanogel system. Novel nanogel systems are discussed with respect to their type of cross-linkage and their suitability as therapeutic delivery systems, as well as their ability to stabilize the protein/peptide drug.

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