Defect-Dominated Shape Recovery of Nanocrystals: A New Strategy for Trimetallic Catalysts

Here we present a shape recovery phenomenon of Pt–Ni bimetallic nanocrystals that is unequivocally attributed to the defect effects. High-resolution electron microscopy revealed the overall process of conversion from concave octahedral Pt₃Ni to regular octahedral Pt₃Ni@Ni upon Ni deposition. Further experiments and theoretical investigations indicated that the intrinsic defect-dominated growth mechanism allows the site-selective nucleation of a third metal around the defects to achieve the sophisticated design of trimetallic Pt₃Ni@M core–shell structures (M = Au, Ag, Cu, Rh). Consideration of geometrical and electronic effects indicated that trimetallic atomic steps in Pt₃Ni@M could serve as reactive sites to significantly improve the catalytic performance, and this was corroborated by several model reactions. The synthesis strategy based on our work paves the way for the atomic-level design of trimetallic catalysts

Sustained Codelivery of Cisplatin and Paclitaxel via an Injectable Prodrug Hydrogel for Ovarian Cancer Treatment

The sustained release of both the hydrophilic drug and hydrophobic drug from one delivery system remains challenging in pharmaceutics and biomaterials science. The combination of hydrophilic cisplatin and hydrophobic paclitaxel (PTX) exhibits a clinical survival advantage compared with the individual drug therapy against various tumors such as ovarian cancer. In this study, a localized, long-term codelivery system of cisplatin and PTX was developed using an injectable and thermosensitive polymer–platinum­(IV) conjugate hydrogel as the carrier. The thermosensitive Bi­(mPEG-PLGA)–Pt­(IV) (PtGel) conjugate was synthesized via covalently linking two mPEG-PLGA copolymers onto a Pt­(IV) prodrug, and its concentrated aqueous solution exhibited a reversible sol–gel transition upon heating. Meanwhile, the core–corona micelles formed by the amphiphilic conjugates in water could serve as a reservoir for the solubilization of PTX, and thus an injectable binary drug-loaded hydrogel formulation was obtained. We also found that the introduction of PTX into the conjugate hydrogel decreased its sol–gel transition temperature and improved its gel strength. In vitro release experiments showed that both of the loaded drugs were released in a sustained manner for as long as 2.5 months, which was the longest combination delivery of these two drugs ever reported. In vitro cellular assays revealed that the dual-drug system exhibited a synergistic anticancer effect against ovarian cancer cells. Finally, using the SKOV-3 ovarian cancer xenograft mouse model, we demonstrated that a single injection of the PTX-loaded conjugate hydrogel system resulted in enhanced anticancer efficacy and significantly reduced the side effects, when compared with the multiple injections of the free drug combination

Summary of morphological data and experimental outcomes.

<p>Different from OVX-Saline:</p><p>* <i>P = 0</i>.<i>0004</i></p><p>** <i>P = 0</i>.<i>0024</i></p><p>Summary of morphological data and experimental outcomes.</p

Significant differences were observed in bone mineral density of the humeral head between the <i>Control</i>, <i>OVX-Saline</i> and <i>OVX-PTH</i> groups.

<p>Bone mineral density in the <i>OVX-PTH</i> group was significantly higher than in the <i>OVX-Saline</i> group but similar to that of the <i>Control</i> group.</p

4-layered tendon-bone interface of ISP enthesis: tendon, nonmineralized fibrocartilage (*), mineralized fibrocartilage (▲) (▲), and bone. (↑) indicates the tidemark.

<p>In the <i>Control</i> and <i>OVX-PTH</i> groups, well-organized ISP enthesis could be observed with a clear tidemark (A, D). Arrangement of nonmineralized fibrocartilage aligned well, nonmineralized and mineralized fibrocartilage were stained deeply and with abundant cells (B, E). In the <i>OVX-PTH</i> group, the nonmineralized and mineralized fibrocartilage were thicker with a more compact structure (E, F). In <i>OVX-Saline</i> group, a relative thinner tendon-bone interface was observed, as well as a less clear tidemark in the enthesis (G). The cell deposition in the area was less compared to the other groups, and osteoclast number and bone lacuna in the mineralized fibrocartilage seemed to have increased compared to both <i>Control</i> and <i>OVX-PTH</i> groups (H, I).</p

The humerus was placed in a custom made fixture and the tendon attached to a cryo-clamp for testing.

<p>Failure was tested at 1 mm/s and the direction of pull of the tendon was directly superior and along the axes of the ISP tendon fibers.</p

Failure Stress vs. BMD.

<p>A positive linear correlation was observed between failure stress and bone mineral density measured at the humeral head.</p

Thermoresponsive Polymeric Nanoparticles as Efficient Pickering Interfacial Catalysts for Selective Oxidation of Sulfides

Pickering emulsions provide a versatile platform for liquid–liquid two-phase reactions; however, the separation and recovery of solid catalysts have always been plagued by strong adsorption at the interfaces. In this study, we developed thermoresponsive polymeric nanoparticles by simply copolymerizing the monomers of N-isopropylacrylamide (NIPAM) and 2,2,6,6-tetramethyl-4-piperidinyl methacrylate (TMPM) and oxidizing the precursor to 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Structural design and molecular modulation give the polymeric catalysts excellent amphiphilicity, which allows them to be tightly adsorbed at the interfaces, thus stabilizing oil-in-water (O/W) Pickering emulsions in biphasic reaction systems. Such emulsion systems with abundant interfacial areas can enhance reaction mass transfer and promote catalytic transformation. More importantly, modulating the wettability of the polymers leads to an oriented distribution of the catalysts at the interfaces, which in turn affects the contact between the substrate molecules and catalyst centers, avoiding overoxidation of the sulfides and improving the selectivity of sulfoxides. As expected, the selectivity of methyl phenyl sulfoxide in Pickering emulsion microreactors was 97.8% with a turnover frequency (TOF) of 10.0 mol mol–1 min–1, which is higher than previously reported results. When the systems warm to 37 °C at the end of the reactions, the amine groups of NIPAM immobilized on the polymer catalysts shrink, causing the particles to become hydrophobic and thus spontaneously desorbed from the interfaces, resulting in demulsification. After recycling ten runs, the polymeric nanocatalysts showed no loss on either conversion or selectivity and maintained stable catalytic activity. The conceptually temperature-responsive Pickering emulsions provide a clean and effective channel to efficiently recycle the polymeric catalysts and promote the catalytic activity of biphasic reactions

Calcitonin-Loaded Thermosensitive Hydrogel for Long-Term Antiosteopenia Therapy

Effective antiosteopenia therapy can be achieved by designing long-term protein/peptide drug delivery systems for bone trabecula restoration. Here we show that a complex of salmon calcitonin and oxidized calcium alginate (sCT-OCA) was prepared and loaded into a thermosensitive copolymer hydrogel for long-term antiosteopenia treatment. The triblock copolymer, poly­(d,l-lactic acid-<i>co</i>-glycolic acid)-<i>b</i>-poly­(ethylene glycol)-<i>b</i>-poly­(d,l-lactic acid-<i>co</i>-glycolic acid) (PLGA-PEG-PLGA) exhibited sol–gel transition at body temperature. The sustained release of sCT from the in situ gelling system was determined by both the degradation of the hydrogel and the decomposition of the sCT-OCA complex. This system showed sustained effects in reducing serum calcium and bone trabecula reconstruction in the treatment of glucocorticoid-induced osteopenia in rats for approximately 30 days after a single subcutaneous injection, which may shed light on antiosteopenia therapy in the future

Additional file 2 of High leukocyte mitochondrial DNA copy number contributes to poor prognosis in breast cancer patients

Supplementary Material