Transition-metal salt-containing silica nanocapsules elaborated via salt-induced interfacial deposition in inverse miniemulsions as precursor to functional hollow silica particles.

Aqueous core-silica shell nanocapsules were successfully prepared using liquid droplets containing transition-metal salt as templates in inverse miniemulsions. The formation of the silica shell was attributed to the interfacial deposition of silica species induced by the presence of the transition-metal salt. In addition to the control of the particle morphology, the incorporated transition-metal salts could be used to derivatize the particles and confer additional functionalities to the hollow silica particles. To demonstrate the derivatization, the magnetic hollow silica particles were prepared by converting iron salts to magnetic iron oxides by heat treatment. The particle morphology, size, and size distribution were characterized by transmission electron microscopy and scanning electron microscopy. The results show that the particle properties strongly depend on the type and the amount of salts, the amount of tetraethoxysilane (TEOS), the pH of the droplets, and the ratios of 2-hydroxyethyl methacrylate to aqueous HCl solution. The specific surface area and pore properties were characterized by N2 sorption measurements. The pore properties and specific surface area could be tuned by varying the amount of salt. Levels of elements and of iron oxides in the magnetic hollow particles were measured by energy-dispersive X-ray spectroscopy. Iron was distributed homogenously with silicon and oxygen in the sample. The magnetization measured by a magnetic property measurement system confirmed the successful conversion of the iron salts to magnetic iron oxides.

Synthesis of cross-linked chitosan-based nanohydrogels in inverse miniemulsion.

Cross-linked chitosan (CS) nanohydrogels were successfully prepared via cross-linking CS nanodroplets in inverse miniemulsions. The cross-linker was transferred to the CS nanodroplets via the evaporation from its aqueous solution and diffusion through the continuous phase. The formation of cross-linked CS nanohydrogels was confirmed by the morphological investigation during the reaction and the successful preparation of acidic aqueous dispersion of CS nanohydrogels. The size and size distribution of the CS nanodroplets and nanohydrogels were characterized by dynamic light scattering (DLS). The particle morphology of CS nanohydrogels was observed by transmission electron microscopy (TEM). The influence of the synthetic parameters on the particle properties and colloidal stability was investigated with respect to sonication time, surfactant type and amount, type of low polarity solvent, and concentration of CS solution. The cross-linked CS nanohydrogels could be easily re-dispersed in water, and showed a pH sensitivity.

[The effect of preparation method on the quality of shen-mai injection].

OBJECTIVE: To investigate the effect of different preparation method on the quality of Shen-mai injection. METHOD: The Shen-mai injection samples were prepared using three different methods. Fingerprints of Shen-mai extracts red ginseng, and its intermediates were obtained using an HPLC analytical procedure. The contents of ginsenoside Rg1, Rc and Rb1, and the gross saponins of Shen-mai extract were quantitatively mensured with HPLC procedures. RESULT: There was significant difference in fingerprints and chemical contents of the injections prepared by the three different methods. CONCLUSION: The quality of Shen-mai injection was greatly influenced by the preparation method. HPLC fingerprinting method can be applied for the determination of the Shen-mai preparations.

Superparamagnetic Fe3O4/Poly(N-isopropyl acrylamide) Nanocomposites Synthesized in Inverse Miniemulsions: Magnetic and Particle Properties.

In the present study, superparamagnetic Fe3O4/poly(N-isopropyl acrylamide) nanocomposites were synthesized by one-step inverse miniemulsion copolymerization of N-isopropyl acrylamide and N,N'-methylene diacrylamide. The loading of Fe3O4 nanoparticles in the nanocomposites was 27 wt%, and the saturation moment of the nanocomposites was 12.4 emu x g(-1). Fe3O4 nanoparticles were prepared through a coprecipitation method. The amount of stabilizer (poly(acrylic acid)) significantly influenced the size and size distribution of the Fe3O4 nanoparticles, and, therefore, their magnetic properties. Superparamagnetism of the Fe3O4 nanoparticles was preserved in the nanocomposites. The effects of synthetic parameters on the particle properties, namely surfactant loading, concentration of ferrofluid, type of lipophobe and initiator, and amount of cross-linker were investigated. Nanocomposites of Fe3O4/poly(N-isopropyl acrylamide) displayed a guava-like morphology, which they could retain after being redispersed in polar solvents.