Biotin-functionalized targeted polydiacetylene micelles.

Polydiacetylene micelles were functionalized with controlled amounts of biotin using bioorthogonal click chemistry. The biotinylated micelles were evaluated in the selective targeting of the MCF-7 cancerous cell line and were shown to be readily internalized. The efficiency of the cellular uptake was correlated to the density of grafted biotin.

Five Easy Pieces. The Total Synthesis of Phosphoiodyn A (and Placotylene A).

The convergent total synthesis of the marine natural product phosphoiodyn A, a nanomolar agonist of human peroxisome proliferator-activated receptor delta (hPPARδ), was achieved in five steps total from commercially available and inexpensive starting materials. The synthesis relies on the unprecedented regioselective hydrozirconation of a terminal acetylene in the presence of a conjugated 1,3-diyne and on ammonolysis of a ß-chlorophosphonic acid monoester. The scheme also provides the newly isolated placotylene A, an inhibitor of bone marrow-derived macrophage (BMM) differentiation.

Reduced pulmonary function and increased pro-inflammatory cytokines in nanoscale carbon black-exposed workers.

BACKGROUND: Although major concerns exist regarding the potential consequences of human exposures to nanoscale carbon black (CB) particles, limited human toxicological data is currently available. The purpose of this study was to evaluate if nanoscale CB particles could be responsible, at least partially, for the altered lung function and inflammation observed in CB workers exposed to nanoscale CB particles. METHODS: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Brunauer-Emmett-Teller were used to characterize CB. Eighty-one CB-exposed male workers and 104 non-exposed male workers were recruited. The pulmonary function test was performed and pro-inflammatory cytokines were evaluated. To further assess the deposition and pulmonary damage induced by CB nanoparticles, male BALB/c mice were exposed to CB for 6 hours per day for 7 or 14 days. The deposition of CB and the pathological changes of the lung tissue in mice were evaluated by paraffin sections and TEM. The cytokines levels in serum and lung tissue of mice were evaluated by ELISA and immunohistochemical staining (IHC). RESULTS: SEM and TEM images showed that the CB particles were 30 to 50 nm in size. In the CB workplace, the concentration of CB was 14.90 mg/m³. Among these CB particles, 50.77% were less than 0.523 micrometer, and 99.55% were less than 2.5 micrometer in aerodynamic diameter. The reduction of lung function parameters including FEV1%, FEV/FVC, MMF%, and PEF% in CB workers was observed, and the IL-1ß, IL-6, IL-8, MIP-1beta, and TNF- alpha had 2.86-, 6.85-, 1.49-, 3.35-, and 4.87-folds increase in serum of CB workers, respectively. In mice exposed to the aerosol CB, particles were deposited in the lung. The alveolar wall thickened and a large amount of inflammatory cells were observed in lung tissues after CB exposure. IL-6 and IL-8 levels were increased in both serum and lung homogenate. CONCLUSIONS: The data strongly suggests that nanoscale CB particles could be responsible for the lung function reduction and pro-inflammatory cytokines secretion in CB workers. These results, therefore, provide the first evidence of a link between human exposure to CB and long-term pulmonary effects.

Enantiomeric differentiation by synthetic helical polymers.

Recent advances in the synthesis of helical polymers and their applications as chiral materials, in particular chiral stationary phases (CSPs), for high-performance liquid chromatography (HPLC) are reviewed with an emphasis on the key role of the helical conformations with one-handedness for the prominent chiral recognition of enantiomers. The historical background of artificial optically active helical polymers is also briefly described.

Polydiacetylene-based electrospun fibers for detection of HCl gas.

Polydiacetylenes (PDAs), a family of conjugated polymers, are very intriguing materials in several aspects. Especially, the stimulus-induced apparent blue-to-red transition of the PDAs has led to the development of a variety of PDA-based chemosensors. In the current work, we synthesized PDA monomers bearing trimethyl amine (PCDA-DMEDA) and incorporated them with Poly(ethylene oxide) (PEO) into electrospun fibers. For the first time, we successfully demonstrated that PDA-based electrospun fibers can be used for the naked-eye detection of HCl gas by simple color change (blue to red).

Stereoselective total synthesis of (+)-oploxyne A, (-)-oploxyne B, and their C-10 epimers and structure revision of natural oploxyne B.

The first total synthesis of recently isolated diacetylene alcohols oploxyne A, oploxyne B, and their C-10 epimers was accomplished. The structure of natural oploxyne B has been revised. The key steps involved are base-induced double elimination of a carbohydrate-derived ß-alkoxy chloride to generate the chiral acetylenic alcohol and Cadiot-Chodkiewicz cross-coupling reaction. The target compounds displayed potent cytotoxicity against neuroblastoma and prostate cancer cell lines.