Improved blood compatibility of rapamycin-eluting stent by incorporating curcumin

This paper dealt with improving the blood compatibility of the rapamycin-eluting stent by incorporating curcumin. The rapamycin- and rapamycin/curcumin-loaded PLGA (poly(d,l-lactic acid-co-glycolic acid)) coatings were fabricated onto the surface of the stainless steel stents using an ultrasonic atomization spray method. The structure of the coating films was characterized by Fourier transform infrared spectroscopy (FTIR). The optical microscopy and scanning electron microscopy (SEM) images of the drug-eluting stents indicated that the surface of all drug-eluting stents was very smooth and uniform, and there were not webbings and "bridges" between struts. There were not any cracks and delaminations on stent surface after expanded by the angioplasty balloon. The in vitro platelet adhesion and activation were investigated by static platelet adhesion test and GMP140 (P-selection), respectively. The clotting time was examined by activated partially prothromplastin time (APTT) test. The fibrinogen adsorption on the drug-loaded PLGA films was evaluated by enzyme-linked immunosorbent assay (ELISA). All obtained data showed that incorporating curcumin in rapamycin-loaded PLGA coating can significantly decrease platelet adhesion and activation, prolong APTT clotting time as well as decrease the fibrinogen adsorption. All results indicated that incorporating curcumin in rapamycin-eluting coating obviously improve the blood compatibility of rapamycin-eluting stents. It was suggested that it may be possible to develop a drug-eluting stent which had the characteristics of not only good anti-proliferation but also improved anticoagulation.     

Copper‐Catalyzed Intermolecular Asymmetric Propargylic Dearomatization of Indoles

The first copper‐catalyzed intermolecular dearomatization of indoles by an asymmetric propargylic substitution reaction was developed. This method provides a highly efficient synthesis of versatile furoindoline and pyrroloindoline derivatives containing a quaternary carbon stereogenic center and a terminal alkyne moiety with up to 86 % yield and 98 % ee.     

An amperometric sensor for uric acid based on ordered mesoporous carbon-modified pyrolytic graphite electrode

A novel amperometric sensor for uric acid based on ordered mesoporous carbon modified pyrolytic graphite electrode was developed. Uric acid oxidation was easily catalyzed by this electrode in a phosphate buffer solution at pH 7.0, with an anodic potential decrease about 140 mV compared to bare pyrolytic graphite electrode. The uric acid level was determined by the amperometric method, at a constant potential of 0.31 mV, the catalytic current of uric acid vs. its concentration showed a good linearity in the range of 1.0 × 10⁻⁶−1.0 × 10⁻⁴ mol L⁻¹, with a correlation coefficient of 0.999. The detection limit was 4.0 × 10⁻⁷ mol L⁻¹. The proposed method could be effectively used for uric acid amperometric sensing in human urine.     

Catalytic asymmetric construction of spirocyclopentaneoxindoles by a combined Ru-catalyzed cross-metathesis/double Michael addition sequence

Biologically important and synthetically challenging spirocyclopentaneoxindoles with four contiguous stereocenters including one spiroquaternary stereocenter have been constructed in good yields (72-87%) with excellent diastereoselectivity (16:1→30:1 dr) and enantioselectivity (93→99% ee) by a combined Ru-catalyzed cross-metathesis/organocatalyzed asymmetric double-Michael addition sequence.     

One-pot microwave synthesis of water-dispersible, ultraphoto- and pH-stable, and highly fluorescent silicon quantum dots

Fluorescent silicon quantum dots (SiQDs) are facilely prepared via one-pot microwave-assisted synthesis. The as-prepared SiQDs feature excellent aqueous dispersibility, robust photo- and pH-stability, strong fluorescence, and favorable biocompatibility. Experiments show the SiQDs are superbly suitable for long-term immunofluorescent cellular imaging. Our results provide a new and invaluable methodology for large-scale synthesis of high-quality SiQDs, which are promising for various optoelectronic and biological applications.     

Ring-opening polymerisation of ɛ-caprolactone catalysed by Brønsted acids

Two new Brønsted acids [2,2′-ethylidene-bis (4,6-di-tert-butylphenol)] phosphoric acid (EDBPPOOH) and (3,3′,5,5′-tetra-tert-butylbiphenyl-2,2′-diol) phosphoric acid (TBPO-POOH) were synthesised and fully characterised by ¹H NMR and ¹³C NMR spectra and mass spectra. The ringopening polymerisation (ROP) of ?-caprolactone (?-CL) catalysed by the two Brønsted acids proceeded at 110°C without a solvent or at ambient temperature in toluene. Experimental results indicated that the two Brønsted acids were efficient catalysts for the ROP of ?-CL with moderate number-average molar mass (Mn) and narrow polydispersity indices (PDI). The catalytic activity of TBPO-POOH is higher than EDBP-POOH in the ROP of ?-CL. After benzyl alcohol was added, it was able to accelerate the polymerisation process. The polymerisation can also occur with the addition of water with a monomer/catalyst/initiator mole ratio of 100: 1: 1. The living polymerisation was ascertained by the linear relationships of the Mn vs. monomer conversion, then it was further confirmed by a second-feed experiment of a double monomer producing double Mn. A kinetic study of the relationships between monomer concentration and time revealed a first-order dependence on monomer concentration in the polymerisation. End-group analysis of ¹H NMR spectra and electrospray-ionisation mass spectra suggests that the two Brønsted acids are capable of catalysing and initiating the ROP of ?-CL.     

Lanthanide‐Catalyzed Reversible Alkynyl Exchange by Carbon–Carbon Single‐Bond Cleavage Assisted by a Secondary Amino Group

Lanthanide‐catalyzed alkynyl exchange through C?C single‐bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β‐alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo‐ and cross‐dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions.     

Through-space charge transfer blue polymers containing acridan donor and oxygen-bridged triphenylboron acceptor for highly efficient solution-processed organic light-emitting diodes

Three kinds of through-space charge transfer(TSCT) blue polymers containing non-conjugated polystyrene backbone together with spatially-separated acridan donor and oxygen-bridged triphenylboron acceptors having different substituents of tert-butyl,hydrogen and fluorine are designed and synthesized. The designed TSCT blue polymers possess photoluminescence quantum yields up to 70% in solid-state film, single-triplet energy splitting below 0.1 eV, and typical thermally activated delayed fluorescence(TADF) effect. Meanwhile, the resulting polymers exhibit aggregation-induced emission(AIE) effect with emission intensity increased by up to ～27 folds from solution to aggregation state. By changing the substituent of acceptors to tune the charge transfer strength, blue emission with peaks from 444 to 480 nm can be realized for the resulting polymers.Solution-processed organic light-emitting diodes based on the polymers exhibit excellent device performance with Commission Internationale de L'Eclairage(CIE) coordinates of(0.16, 0.27), together with the maximum luminous efficiency of 30.7 cd A~(-1) and maximum external quantum efficiency of 15.0%, which is the best device efficiency for blue TADF polymers.     

Channel‐Rich RuCu Nanosheets for pH‐Universal Overall Water Splitting Electrocatalysis

Channel‐rich RuCu snowflake‐like nanosheets (NSs) composed of crystallized Ru and amorphous Cu were used as efficient electrocatalysts for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting in pH‐universal electrolytes. The optimized RuCu NSs/C‐350 °C and RuCu NSs/C‐250 °C show attractive activities of OER and HER with low overpotentials and small Tafel slopes, respectively. When applied to overall water splitting, the optimized RuCu NSs/C can reach 10 mA cm^?2 at cell voltages of only 1.49, 1.55, 1.49 and 1.50 V in 1 m KOH, 0.1 m KOH, 0.5 m H₂SO₄ and 0.05 m H₂SO₄, respectively, much lower than those of commercial Ir/C∥Pt/C. The optimized electrolyzer exhibits superior durability with small potential change after up to 45 h in 1 m KOH, showing a class of efficient functional electrocatalysts for overall water splitting.