Nano-hybrid carboxymethyl-hexanoyl chitosan modified with (3-aminopropyl)triethoxysilane for camptothecin delivery.

Silane-modified amphiphilic chitosan was synthesized by anchoring a silane coupling agent, (3-aminopropyl)triethoxysilane, to a novel amphiphilic carboxymethyl-hexanoyl chitosan (CHC). The chemical structure of this new organic-inorganic hybrid molecule was characterized by FTIR and 13C-, 29Si-nuclear magnetic resonance, while the structural evolution was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). Experimental results indicated a self-assembly behaviour of molecules into nanoparticles with a stable polygonal geometry, consisting of ordered silane layers of 6 nm in thickness. The self-assembly property was found to be influenced by chemical composition and concentration of silane incorporated, while the size can be varied by the amount of anchored silane. It was also demonstrated that such vesicle exhibited excellent cytocompatibility and cellular internalization capability in ARPE-19 cell line, and presented well-controlled encapsulation and release profiles for (S)-(+)-camptothecin. These unique properties render it as a potential drug delivery nanosystem.

Synthesis and optical properties of white-light-emitting alumina/ZnO nanotubes.

A simple chemical solution process was used to prepare alumina nanoparticle-coated ZnO nanotubes (ANZTs). Transmission electron microscope (TEM) images proved that the alumina nanoparticles were uniformly dispersed on the ZnO nanotubes. After thermal treatment at different temperatures under various atmospheres, photoluminescence (PL) measurements showed that the ANZTs emitted a variety of colors, including blue, green and white light. Gaussian curve fitting of the PL spectra revealed that the competition between the blue, blue-green, green and yellow band emissions and their relative emission intensities were strongly associated with various defects. Blue emission was attributed to large numbers of oxygen defects in alumina, while green and yellow emissions were related to oxygen and zinc defects in ZnO, respectively. Under specific conditions, white light, consisting of blue, blue-green, green and yellow band emissions, was obtained. Further TEM analysis indicated that the defect structure of ANZTs could be manipulated by the interface interaction between alumina and the ZnO nanotubes.

Core/Single-Crystal-Shell Nanospheres for Controlled Drug Release via a Magnetically Triggered Rupturing Mechanism.

Core/single-crystal-shell nanospheres are constructed from a poly-(N-vinyl- 2-pyrrolidone) (PVP)-modified silica core with an outer layer of single-crystal iron oxide shell. The nanospheres show outstanding release-and-zero-release characteristics via the addition and removal, respectively, of an external high-frequency magnetic field.