Preparation and characterization of N-isopropylacrylamide/carboxymethylated chitosan hydrogel

Poly （N-isopropylacrylamide） （PNIPAAm）/carboxymethylated chitosan （CMCH） hydrogels were prepared by irradiating the aqueous solution mixture of NIPAAm and CMCH by 60 Co γ-ray.The effects of feed ratio of NIPAAm and CMCH,temperature,pH and ionic strength on the swelling ratio of PNIPAAm/CMCH hydrogels were studied.The results show that the addition of CMCH shifts the lower critical solution temperature （LCST） of the PNIPAAm hydrogel to higher temperature.The PNIPAAm/CMCH hydrogel displays not only pH-and thermo-sensitivity,but also ion-sensitivity.Differential scanning calorimetry （DSC） was applied for the determination of the LCST of the hydrogel.     

Emerging hemostatic materials for non-compressible hemorrhage control

Non-compressible hemorrhage control is a big challenge in both civilian life and the battlefield, causing a majority of deaths among all traumatic injury mortalities. Unexpected non-compressible bleeding not only happens in pre-hospital situations but also leads to a high risk of death during surgical processes throughout in-hospital treatment. Hemostatic materials for pre-hospital treatment or surgical procedures for non-compressible hemorrhage control have drawn more and more attention in recent years and several commercialized products have been developed. However, these products have all shown non-negligible limitations and researchers are focusing on developing more effective hemostatic materials for non-compressible hemorrhage control. Different hemostatic strategies (physical, chemical and biological) have been proposed and different forms (sponges/foams, sealants/adhesives, microparticles/powders and platelet mimics) of hemostatic materials have been developed based on these strategies. A summary of the requirements, state-of-the-art studies and commercial products of non-compressible hemorrhage-control materials is provided in this review with particular attention on the advantages and limitations of their emerging forms, to give a clear understanding of the progress that has been made in this area and the promising directions for future generations.     

A fast and versatile cross-linking strategy via o-phthalaldehyde condensation for mechanically strengthened and functional hydrogels

Fast and catalyst-free cross-linking strategy is of great significance for construction of covalently cross-linked hydrogels. Here, we report the condensation reaction between o-phthalaldehyde (OPA) and N-nucleophiles (primary amine, hydrazide and aminooxy) for hydrogel formation for the first time. When four-arm poly(ethylene glycol) (4aPEG) capped with OPA was mixed with various N-nucleophile-terminated 4aPEG as building blocks, hydrogels were formed with superfast gelation rate, higher mechanical strength and markedly lower critical gelation concentrations, compared to benzaldehyde-based counterparts. Small molecule model reactions indicate the key to these cross-links is the fast formation of heterocycle phthalimidine product or isoindole (bis)hemiaminal intermediates, depending on the N-nucleophiles. The second-order rate constant for the formation of phthalimidine linkage (4.3 M⁻¹ s⁻¹) is over 3000 times and 200 times higher than those for acylhydrazone and oxime formation from benzaldehyde, respectively, and comparable to many cycloaddition click reactions. Based on the versatile OPA chemistry, various hydrogels can be readily prepared from naturally derived polysaccharides, proteins or synthetic polymers without complicated chemical modification. Moreover, biofunctionality is facilely imparted to the hydrogels by introducing amine-bearing peptides via the reaction between OPA and amino group.     

新型超分子凝胶材料

作为新型的凝胶材料,超分子凝胶的制备受到越来越多的关注.基于超分子自组装的方法,制备了响应性超分子凝胶、氢键组装超分子凝胶、有机无机杂化超分子凝胶、主客体超分子凝胶等凝胶材料.文章主要综述了这几种超分子凝胶的制备策略,并对其进一步研究进行了展望.     

响应性水凝胶材料的应用

刺激响应现象是自然界中普遍存在的一种现象.目前科研人员广泛研究的响应性凝胶材料可以根据外界刺激因素的变化产生响应性溶胀行为.响应性水凝胶已经成为制备功能化材料的重要骨架材料,近年来,科研人员已构建了pH响应水凝胶、温度响应水凝胶和光反应水凝胶等水凝胶材料,并利用水凝胶骨架构建了功能化材料.     

全麻手术病人应用医用水凝胶护眼贴效果分析

目的：探讨全麻手术需特殊体位病人在应用医用水凝胶护眼贴后对预防眼睑水肿、结膜红肿等眼部并发症的效果。方法选择120例脊柱手术俯卧位全麻病人和食管癌手术侧卧位全麻病人,将其随机分为两组,各60例。试验组60例直接使用医用水凝胶护眼贴保护双眼,对照组60例采用金霉素眼膏结合3M 透明敷料贴保护双眼。观察术后24小时眼部并发症发生情况。结果术后24小时回访,试验组术后患者眼睑水肿2例、结膜红肿2例、视物模糊3例、畏光3例、黏滞感2例、异物感4例;对照组术后患者眼睑水肿9例、结膜红肿13例、视物模糊13例、畏光11例、黏滞感9例、异物感17例。两组间差异有统计学意义。结论特殊手术体位全麻病人术中使用护眼贴能更有效保护双眼,预防眼部并发症的发生。     

pH值敏感水凝胶的合成及药物缓释性能研究

聚乙二醇(PEG)与丙烯酰氯反应合成聚乙二醇双丙烯酸酯(PEGDA)，然后以PEGDA、N—乙烯基—2—此咯烷酮(NVP)及丙烯酸为主要原料，N，N^ —亚甲基双丙烯酰胺(BIS)为交联剂，偶氮二异丁腈(AIBN)为引发剂，采用自由基聚合法合成了对pH值变化敏感的N—乙烯基—2—吡咯烷酮—丙烯酸—聚乙二醇双丙烯酸酯交联共聚物(po1y[NVP-AA-PEGDA])水凝胶．利用该共聚物为载体对抗癌药5—氟脲密啶(5—FU)进行包埋，并在SIF及SGF缓冲溶液中于37℃进行体外释药研究．结果表明，在pH值较小的缓释介质中药物释放曲线较平缓，释药周期较长，同时最终的平衡释药百分数也较小；随着样品中PEGDA量的减少，释药曲线趋于平缓，释药周期变长，最终的平衡释药百分数成小．     

温敏凝胶对食用菌含盐废水中有机物的浓缩作用

以具有温度敏感性的聚（N-异丙基丙烯酰胺）（PNIPA）水凝胶对食用菌含盐废水进行有机物浓缩,考查了不同浓度的PNIPA水凝胶在不同凝胶/废盐水比条件下对废盐水中有机物的浓缩效果。发现PNIPA水凝胶对食用菌含盐废水中有机物能起到很好的浓缩作用,凝胶中PNIPA浓度为10%的凝胶对食用菌含废水中有机物的浓缩效果最好。     

Surface cleaning? Yes,freshly grated Agar gel,please

Polysaccharide-based rigid hydrogels are by now well-established means for delivering water or, more generally an aqueous solution, to a surface in a controllable way so as to minimize diffusion and possible side-effects on water-sensitive materials during cleaning treatments. These gels can be applied as pre-formed solid bricks on planar surfaces or brushed onto objects in a semi-solid state. In this note, a different application procedure is presented, suitable for surface cleaning treatments of sensitive painted surfaces: pre-formed rigid gels grated to tiny particles that can be brushed onto the surface. A general discussion on the strategies that can be adopted when water is required to clean a water-sensitive soiled surface is presented, then the new procedure is discussed and a representative case study is shown, supporting the procedure described.     

Hydrolates and Gellan: An Eco-innovative Synergy for Safe Cleaning of Paper Artworks

The gellan hydrogel is used as a cleaning agent for paper artworks. The purposes of this work were to give the gellan hydrogel both a microbial resistance and a cytocidal action against the biodeteriogens using hydrolates. Broth microdilution assays were performed to identify the fungicidal action of 16 hydrolates vs 3 fungal strains. The study concerned the Minimal Fungicidal Concentration and pH, colour, and ultra-structural variations on all paper samples, by placing them in contact with GELYD (GELlan?+?hYDrolat). The in vitro tests showed that eight out of 16 hydrolates strongly inhibited fungal growth, but only two of them (Monarda fistulosa, Citrus aurantium subsp amara) showed in situ fungicidal action. Data indicate a new and interesting eco-innovative use of hydrolates, since GELYD is able not only to clean paper artworks, but also to kill the fungal cells present on paper that are potentially harmful for paper and operators.