Quasi-solid-state electrolyte for rechargeable high-temperature molten salt iron-air battery

Molten salts are a unique type of electrolyte enabling high-temperature electrochemical energy storage (EES) with unmatched reversible electrode kinetics and high ion-conductivities, and hence impressive storage capacity and power capability. However, their high tendency to evaporate and flow at high temperatures challenges the design and fabrication of the respective EES devices in terms of manufacturing cost and cycling durability. On the other hand, most of these EES devices require lithium-containing molten salts as the electrolyte to enhance performances, which not only increases the cost but also demands a share of the already limited lithium resources. Here we report a novel quasi-solid-state (QSS) electrolyte, consisting of the molten eutectic mixture of Na2CO3-K2CO3 and nanoparticles of yttrium stabilized zirconia (YSZ) in a mass ratio of 1:1. The QSS electrolyte has relatively lower volatility in comparison with the pristine molten Na2CO3-K2CO3 eutectic, and therefore significantly suppresses the evaporation of molten salts, thanks to a strong interaction at the interface between molten salt and YSZ nanoparticles at high temperatures. The QSS electrolyte was used to construct an iron-air battery that performed excellently in charge-discharge cycling with high columbic and energy efficiencies. We also propose and confirm a redox mechanism at the three-phase interlines in the negative electrode. These findings can help establish a simpler and more efficient approach to designing low-cost and high-performance molten salt metal-air batteries with high stability and safety

Reduction of decoy receptor 3 enhances TRAIL-mediated apoptosis in pancreatic cancer.

Most human pancreatic cancer cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the mechanisms by which pancreatic cancer cells utilize their extracellular molecules to counteract the proapoptotic signaling mediated by the TNF family are largely unknown. In this study, we demonstrate for the first time that DcR3, a secreted decoy receptor that malignant pancreatic cancer cells express at a high level, acts as an extracellular antiapoptotic molecule by binding to TRAIL and counteracting its death-promoting function. The reduction of DcR3 with siRNA unmasked TRAIL and greatly enhanced TRAIL-induced apoptosis. Gemcitabine, a first-line drug for pancreatic cancer, also reduced the level of DcR3. The addition of DcR3 siRNA further enhanced gemcitabine-induced apoptosis. Notably, our in vivo study demonstrated that the therapeutic effect of gemcitabine could be enhanced via further reduction of DcR3, suggesting that downregulation of DcR3 in tumor cells could tip the balance of pancreatic cells towards apoptosis and potentially serve as a new strategy for pancreatic cancer therapy

DcR3 siRNA enhanced gemcitabine-induced apoptosis.

<p>AsPC-1 or MiaPaCa-2 cells were transfected with 10 nM of control siRNA or DcR3 siRNA, respectively. After 24 hours, the cells were treated with gemcitabine (250 or 25 nM, respectively) for 24 hours. Cells were harvested and subjected to flow cytometry for the sub-G1 fraction (<b>A</b> and <b>C</b>) or Western blotting for cleaved PARP (<b>B</b> and <b>D</b>). The combination of DcR3 siRNA and gemcitabine significantly enhanced the proapoptotic effect.</p

DcR3 siRNA enhanced the antitumor effect of gemcitabine.

<p>Control siRNA and DcR3 siRNA-transfected AsPC-1 cells (2×10⁶/site) were subcutaneously injected into nude mice (8 mice/group) and allowed to establish for 7 days. Thereafter, the established tumors were treated with 100 mg/kg of gemcitabine or vehicle (PBS) via intravenous injection twice weekly for 4 weeks. (<b>A</b>) The tumor growth curve was calculated from tumor sizes measured twice weekly. The reduction of DcR3 enhanced the antitumor effect of gemcitabine. (<b>B</b>) Tumors were weighed at the end of the experiment. * <i>P</i><0.05, tumors in the gemcitabine-treated groups versus in untreated groups in vector-transfected AsPC-1 cells; $* <i>P</i><0.05, tumors in siRNA transfectants versus in vehicle transfectants with gemcitabine treatment. (<b>C</b>) The reduction of DcR3 in tumor tissues with different treatments determined with an ELISA. * <i>P</i><0.05, DcR3 in untreated tumors versus in gemcitabine-treated tumors formed by vector-transfected AsPC-1 cells; ** <i>P</i><0.05, DcR3 in tumor control siRNA versus in DcR3 siRNA-transfected AsPC-1 cells;$ <i>P</i><0.05, DcR3 in untreated tumors versus in gemcitabine-treated tumors formed by DcR3 siRNA-transfected AsPC-1 cells. (<b>D</b>) Western blotting was performed in tumor lysate (30 μg/sample) collected from each group and stained with primary antibodies of anti-TRAIL, anti-DcR3, anti-cleaved PARP, and anti-GAPDH (as loading control).</p

Interaction of DcR3 with TRAIL.

<p>Biocore assays, flow cytometry, Western blot, and ELISA-like binding assays were performed to determine the physical interaction between DcR3 and TRAIL. (<b>A</b>) <b>Biacore analysis.</b> The binding curve of TRAIL to DcR3 was determined at different concentrations (1–2048 nM). The control <i>K_eq</i> of recombinant human LIGHT to DcR3 was 13.2 nM, while the <i>K_eq</i> of TRAIL to DcR3 was 52.8 nM. (<b>B</b>) <b>Flow cytometry for DcR3 with TRAIL on the cell surface.</b> Suspended AsPC-1 cells were incubated first with PBS, TRAIL (5 μg/ml) without (lane 2) or with DcR3 (lane 4), recombinant DcR3 (lane 3), or mouse anti-TRAIL MAb (1 μg/ml) with DcR3 (lane 5). Thereafter, 5 μg/ml of biotinylated anti-DcR3 was added to determine the binding of DcR3 on cell surface with flow cytometry. (<b>C and D</b>) <b>Flow cytometry for exposed TRAIL.</b> Gemcitabine was added to AsPC-1 (0–1000 nM) or MiaPaCa-2 (0–100 nM) cells to stimulate the expression of TRAIL. Cells were also treated with PBS, 10 nM of DcR3 siRNA (to reduce the binding and masking of TRAIL), or additional recombinant DcR3 (to block the accessing of anti-TRAIL) to detect TRAIL by flow cytometry. (<b>E and F</b>) <b>Colocalization of DcR3 and TRAIL.</b> AsPC-1 cells treated without (as control) or with 500 nM of gemcitabine (to enhance the expression of TRAIL) were stained with anti-TRAIL-PE and anti-DcR3-FITC. Doublestained cells were assessed with flow cytometry. (<b>G to L</b>) <b>Immunoprecipitation and Western blotting for DcR3-TRAIL complex.</b> 70-kDa DcR3-TRAIL complex in 100 μl of pure DcR3 and TRAIL mixture (<b>G</b> and <b>H</b>), lysate (<b>I</b> and <b>J</b>), or culture media (<b>K</b> and <b>L</b>) of AsPC-1 cells was captured with McAb anti-DcR3 (<b>G, I, K</b>) or anti-TRAIL (<b>H, J, L</b>) McAb and immobilized with 30 μl of protein A beads. The complex of McAb-DcR3-TRAIL was eluted with Laemmli buffer and subjected to Western blotting with biotinylated anti-TRAIL (<b>G,. </b><b>I, K</b>) or anti-DcR3 (<b>H, J, L</b>) followed by SA-HRP and ECL detector. (<b>M and N</b>) <b>Binding competition between free and immobilized forms of DcR3 and TRAIL. </b><b>M</b>: After 100 μl of 1 μg/ml recombinant TRAIL or FasL was immobilized on an ELISA plate, 1 μg/ml of DcR3 was added without (no competition group) or with 10 μg/ml of TRAIL or FasL (competition group) or boiled TRAIL or FasL (no function protein control), followed by biotinylated anti-DcR3 and SA-HRP and TMB substrate. <b>N</b>: DcR3 was immobilized on an ELISA plate. TRAIL and FasL were used as ligands without or with boiled or functional 10 μg/ml of TRAIL or FasL in the presence of DcR3, followed by biotinylated anti-TRAIL or anti-FasL, and SA-HRP and TMB substrate.</p

DcR3 siRNA enhanced TRAIL-induced apoptosis.

<p>AsPC-1 or MiaPaCa-2 cells were transfected with 10 nM of control siRNA or DcR3 siRNA, respectively. After 24 hours, the cells were treated with recombinant FasL, LIGHT, or TRAIL (100 ng/ml for AsPC-1 and 20 ng/ml for MiaPaCa-2 cells) for 24 hours. Cells were harvested and subjected to flow cytometry for the sub-G1 fraction (<b>A</b> and <b>C</b>) or Western blotting for cleaved PARP (<b>B</b> and <b>D</b>). DcR3 siRNA significantly enhanced TRAIL-induced apoptosis (<i>P</i><0.05).</p

Biacore analysis for TRAIL or LIGHT binding to Recombinant DcR3.

<p><i>K_a</i>, association rate constant; <i>K_d</i>, dissociation rate constant; <i>K</i><b><i>_eq</i></b>, equilibrium constant.</p