Biomimetic Nucleation of Metal-Organic Frameworks on Silk Fibroin Nanoparticles for Designing Core-Shell-Structured pH-Responsive Anticancer Drug Carriers.

Silk fibroin (SF) is a biomacromolecule that can be assembled into nanostructures and induce biomimetic nucleation of inorganic materials. Zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), can be dissolved selectively under acidic pH. Here, we integrated SF and ZIF-8 to develop novel drug carriers that selectively release drug in the acidic intracellular environment of cancer cells. Specifically, SF was assembled into nanoparticles (SF-NPs), which were then loaded with an antitumor drug, doxorubicin (DOX), to form DSF-NPs. Due to the SF-mediated organization of ZIF-8 precursors such as zinc ions, the DSF-NPs further templated the nucleation of ZIF-8 onto their surface to generate core-shell-structured NPs (termed DSF@Z-NPs) with ZIF-8 as a shell and DSF-NP as a core. We found that the DSF@Z-NPs, highly stable under neutral conditions, could be uptaken by breast cancer cells, release DOX selectively owing to dissolution of ZIF-8 shells in the acidic intracellular environment in a controlled manner, and induce cell apoptosis. We also confirmed that the DSF@Z-NPs could inhibit tumor growth more efficiently to reach a higher survival rate than their controls by inducing cell apoptosis in vivo. Our study suggests that SF and MOF could be combined to design a new type of cancer therapeutics.

[Pre- and post-iodine nutritional status among the population related to the practice of new standard on edible iodized salt, in Yunnan province].

OBJECTIVE: In order to understand the iodine nutritional status, after the salt-iodine content was showed a reduction in 2012 and to evaluate the current situation after the new standards was brought into force to the general population in an experimental community of Yunnan province. METHODS: Randomly sampled urine and salt were collected, to test the iodine concentration in the study-site. Pre-and post-levels of the iodized salt under the provision of the new standards, were identified. RESULTS: of this study were gathered upon 3 weeks or 3 months, respectively. Results Data from the three randomly chosen study sites showed that the urine iodine concentration in the general populations was reducing gradually. In the general population, medians of Urine Iodine (MUI) were 279.71 µg/L, 239.64 µg/L and 226.26 µg/L, respectively. Proportion of the urine iodine value for 100-199 µg/L increased but ≥300 µg/L decreased, after the new standard was put into practice. Both homogeneity and stability of the new standard on iodized salt seemed to be good. CONCLUSION: Iodine nutrition in general population appeared reasonable under the use of newly set salt-iodine standards in general population living in Yunnan province.

Preparation of highly optically pure homochiral sulfide-containing alcohols via oxazaborolidine-catalyzed asymmetric borane reduction of ketones.

Highly optically pure homochiral 1-(4-alkylthiophenyl) alcohols were prepared efficiently and practically via the oxazaborolidine-catalyzed asymmetric borane reduction of prochiral ketones in toluene at 25 degrees C. The coordination of the sulfur atom in the ketones to the boron atom in the catalyst and borane can be inhibited under these reduction conditions.