Abstract:The poor patency rate following small-diameter vascular grafting remains a major hurdle for the widespread clinical application of artificial blood vessels to date. Our previous studies found that electrospun poly(L-lactide-co-epsilon-caprolactone) (P[LLA-CL]) nanofibers facilitated the attachment and growth of endothelial cells (EC), and heparin incorporated into P(LLA-CL) nanofibers was able to release in a controlled manner. Hence, we hypothesized that heparin-bonded P(LLA-CL) vascular scaffolds with autologous EC pre-endothelialization could significantly promote the graft patency rate. To construct a small-diameter vascular scaffold, the inner layer was fabricated by heparin-bonded P(LLA-CL) nanofibers through coaxial electrospinning, while the outer layer was woven by pure P(LLA-CL) nanofibers. Except dynamic compliance (5.4 ± 1.7 versus 12.8 ± 2.4 × 10 −4 /mmHg, P , 0.05), maximal tensile strength, burst pressure, and suture retention of the composite, scaffolds were comparable to those of canine femoral arteries. In vitro studies indicated that the scaffolds can continuously release heparin for at least 12 weeks and obtain desirable endothelialization through dynamic incubation, which was confirmed by EC viability and proliferation assay and scanning electronic microscopy. Furthermore, in vivo studies demonstrated that pre-endothelialization by autologous ECs provided a better effect on graft patency rate in comparison with heparin loading, and the united application of pre-endothelialization and heparin loading markedly promoted the 24 weeks patency rate of P(LLA-CL) scaffolds (88.9% versus 12.5% in the control group, P , 0.05) in the canine femoral artery replacement model. These results suggest that heparin-bonded P(LLA-CL) scaffolds have similar biomechanical properties to those of native arteries and possess a multiporous and biocompatible surface to achieve satisfactory endothelialization in vitro. Heparin-bonded P(LLA-CL) scaffolds with autologous EC pre-endothelialization have the potential to be substitutes for natural small-diameter vessels in planned vascular bypass surgery.

Four new tetrazole–carboxylate ligands have been reacted with zinc salts, resulting in the formation of four compounds with enhanced luminescence properties and structures that are controlled by the number, different coordination modes and substitution of the ligands.

The use of mineral fillers in cellulosic paper products can result in cost/energy savings and improvement of paper properties. However, the increase in filler addition levels is hampered by the negative impact of fillers on paper strength, poor filler retention, etc. As an attempt to improve the use of fillers in papermaking, filler modification with the combination of cationic starch and carboxymethyl cellulose was preliminarily explored in this mini-study. This concept was compared with filler modification with either cationic starch or carboxymethyl cellulose. The combination of cationic starch with carboxymethyl cellulose resulted in improved attachment of the starch to the filler, possibly suggesting the in-situ formation of polymer complexes with lower solubility than starch. With respect to filler retention, tensile strength, brightness, and opacity of the filled paper, the combined use of cationic starch and carboxymethyl cellulose resulted in a modified filler material with modestly better performance, in comparison to filler modification with either cationic starch or carboxymethyl cellulose. The combined use of a cationic polymer and an anionic polymer to modify fillers may provide an alternative approach to improving the use of mineral fillers in the paper industry.

Summary: Molecularly imprinted polymers with specific recognition to salicylic acid (SA-MIPs) were prepared by oil-in-water emulsion polymerization using salicylic acid as template, acrylamide as functional monomer, and ethylene glycol dimethacrylate as crosslinker. The morphology and size distribution of the SA-MIPs were detected by SEM and photon cross correlation spectrometry. Equilibrium binding experiments and Scatchard analyses were carried out to investigate the selectivity of the SA-MIPs. The results show that the SA-MIPs exhibit a higher affinity and selectivity to salicylic acid than to m-hydroxybenzoic acid and sulfosalicylic acid. Two classes of binding sites were produced in the SA-MIPs and the equilibrium dissociation constants were estimated to be 2.03 and 9.97 mmol/L, respectively.

Key indicatorsSingle-crystal X-ray study T = 298 K Mean (C-C) = 0.019 Å R factor = 0.058 wR factor = 0.133 Data-to-parameter ratio = 14.0For details of how these key indicators were automatically derived from the article, see