原位交联羧甲基壳聚糖/碳酸钙凝胶海绵的制备及其止血性能研究

以羧甲基壳聚糖(CMCS)、碳酸钙(CaCO₃)、葡萄糖酸内酯(GDL)和甘油(GLY)为原料，通过原位相转变制备水凝胶，经冷冻干燥工艺得到止血海绵，用于躯体非压迫性出血。通过扫描电镜、吸水率、孔隙率、溶血实验和全血凝固时间测试分别对海绵的理化性能、血液安全性、止血性能进行研究。当CaCO₃与CMCS的质量比为15%时，制得的海绵综合性能最好。该海绵呈疏松多孔片层状，止血时间较医用棉纱布材料缩短了35%,无血液毒性，是一种优良的止血海绵材料。     

织构气体扩散层表面氢氧燃料电池阴极超低Pt载量催化层的磁控溅射法制备

采用磁控溅射技术在具有织构结构的气体扩散层(GDL)表面制备了可应用于氢氧质子交换膜燃料电池的超低Pt载量阴极催化层, 并通过SEM、 轮廓仪和XRD等测试方法表征了GDL及其载Pt后的形貌和物相, 利用XPS分析溅射Pt的化学价态, 使用电池测试台表征其电池性能. 测试结果表明, 磁控溅射法在GDL表面沉积的Pt催化层载量可控且分布均匀; 与商业GDL对比, Pt在织构GDL表面具有更大的可附着面积. 电池性能测试结果显示, 当Pt载量为0.04 mg/cm²时, 以织构GDL作基材的样品质量比功率高达26.25 kW/g Pt, 远大于商业GDL作基材时的17.76 kW/g Pt, 也大于同等Pt载量下商业Pt/C催化剂的24.00 kW/g Pt.     

生物基高分子型止血材料和伤口敷料

伤口的快速止血和愈合对人类的生命保障和身体健康有十分重要的影响,使得伤口护理材料的研究备受关注。其中,从动植物中提取或由生物基单体合成而得的生物基高分子材料,因具有良好的物理性能、生物活性、生物相容性、生物降解性和生物可吸收性等优点,被人们通过物理或化学方法,进行改性或药物负载,制成具有止血、杀菌、保护和促进伤口愈合等功能的止血材料和伤口敷料。本文从化学组成、制备方法、材料结构、评价方法和生物活性等多角度综述了近年来(特别是近5年来)聚乳酸、壳聚糖、海藻酸钠、透明质酸、蛋白质和聚磷酸盐等常见的生物基高分子在止血材料和伤口敷料方面的国内外研究进展,并分析对比了国内外研究水平。展望未来的研究和发展方向,在原料的种类拓宽、材料的多功能化和仿生化等方面仍待努力。     

可吸收止血材料的研究与应用进展

在意外事故及手术中,不可控的大量出血是导致人员死亡的主要原因。性能优越的可吸收止血材料能够加快凝血过程,从而挽救患者生命,提高存活率。由于可吸收止血材料具有生物可降解性能,在完成止血功能后,无需再次取出,安全高效。近年来基于不同的止血机理的、性能优越的止血材料和止血产品层出不穷,在体表止血和手术止血中发挥了重要的作用。本文综述了国内外可吸收止血材料及产品应用情况,并对可吸收止血材料的研究方向进行了展望。     

光响应智能生物粘附材料的设计与应用

智能生物粘附材料是一类通过生物粘附作用粘附于组织表面,且对外界刺激具有特定响应的新型粘合剂.因其止血快、生物相容性好、生物粘附性强且具有智能响应效果而在外科临床应用领域受到了极大的关注.其中,光响应生物粘附材料因具有无接触、时空调节、严格剪裁和远程控制等独特优势,被广泛用于伤口止血及组织修复等领域.除了广泛应用的紫外光,可见光和近红外光因其优异的组织穿透深度、高稳定性和低能量特性而在这类光响应生物粘附材料中受到广泛关注.本文总结了智能响应粘附材料的响应类型,重点介绍了近年来光响应生物粘附材料的研究进展,包括分类、性能及其在生物医学领域的具体应用等.     

高效液相色谱法测定卡格列净中葡萄糖酸-δ-内酯的含量

提出了高效液相色谱-电雾式检测器法(HPLC-CAD)测定卡格列净中葡萄糖酸-δ-内酯(GDL)的含量。优化的色谱条件如下:Thermo Hypersil Gold Aq色谱柱(250 mm×4.6 mm,5μm),流动相为乙腈(9+1)混合溶液,流量0.5mL·min~(-1),柱温30℃,进样量10μL;电雾式检测器(CAD)的雾化温度为50℃,载气压力427.5kPa。在上述的色谱条件下,GDL的线性范围为1.05~22.5mg·L~(-1),GDL的检出限(3S/N)为0.32ng。在3个浓度水平上进行加标回收试验,测得回收率在96.2%~103%之间。供试品加标溶液和对照品溶液在室温条件下放置12h内稳定,测定值的相对标准偏差(n=7)分别为1.8%,1.3%。     

钙离子诱导的海藻酸钠/黄原胶凝胶化临界行为研究

研究了海藻酸钠/黄原胶混合体系的相行为及其对海藻酸钠-钙离子凝胶化临界行为的影响.当海藻酸钠浓度为0.5 wt%时,随着黄原胶的添加,混合体系出现相容、相分离及液晶3种不同的相行为.与纯黄原胶溶液相比,海藻酸钠/黄原胶混合溶液在更低的黄原胶浓度下开始形成液晶,这是由于混合体系中相分离的发生导致了黄原胶有效浓度升高.利用葡萄糖酸内酯(GDL)在线酸化Ca-EDTA,释放钙离子,研究了不同钙离子引入量时(f=[Ca2+]/[COO-])混合体系的黏弹性.Winter-Chambon分析发现临界凝胶点(f gel)随黄原胶浓度的增加而降低.当相分离发生时,临界凝胶点急剧降低,当液晶结构形成后,临界凝胶点呈现上升趋势.通过对比Winter-Chambon方法和临界凝胶点模量松弛法所测得的松弛临界指数(nw和nr),发现黄原胶的添加使海藻酸钠临界凝胶失去结构自相似性.相分离的发生导致临界凝胶结构排列更加致密,而液晶的出现使临界凝胶结构排列相对疏松.     

9,10-蒽醌-2-磺酸钠盐掺杂对导电聚吡咯电容性能的促进作用

用恒电位法制成以9,10-蒽醌-2-磺酸钠盐(AQS)为掺杂阴离子的导电聚吡咯(PPy)电化学电容器电极材料,并采用循环伏安(CV)、充放电测试、电化学阻抗(EIS)等方法表征电容性质.结果表明,与高氯酸阴离子(ClO4-)掺杂的PPy相比,PPy/AQS电极材料不仅单位质量电容和电极稳定性得到提高,工作电压范围也得以扩大.在1mol·L-1的氯化钾中,工作电压为-0.6至0.6V,扫描速率为50mV·s-1时其单位质量电容达到491F·g-1,比PPy/ClO4-电极材料提高1.5倍.这是由于AQS自身良好的氧化还原活性和AQS掺杂有利于聚吡咯膜形成疏松多孔的纳米及亚微米颗粒结构而导致的.     

聚集诱导发光有机氟化合物的研究进展

聚集诱导发光(aggregation-induced emission, AIE)化合物因在生物和化学传感、发光材料、显示等领域具有重要价值而备受关注.作为一类重要的功能分子,有机氟化合物在化学和材料等领域被广泛研究.汇总了具有聚集诱导发光性质的有机氟化合物,并进行了分类讨论.AIE有机氟化合物包括氟代的四苯基乙烯(TPE)衍生物、二苯乙烯基蒽(DSA)衍生物、氰基二苯基乙烯衍生物和二苯乙烯基苯衍生物等常见的AIE化合物,也包括聚合物、碳硼烷簇合物和室温磷光化合物,还有其它一些含氟结构.AIE化合物氟代后,稳定性一般会提高,氟原子参与分子间相互作用,导致聚集态的结构发生改变,从而导致发光性质的改变,如发光增强、发光波长红移(蓝移)或发光量子效率及发光寿命提高等.最后,对AIE有机氟化合物的研究前景进行了展望.     

壳聚糖/海藻酸盐作为新型止血材料的研究进展

有效止血是减轻患者痛苦,降低死亡率的关键,止血材料必须具备良好的止血性、生物相容性、可生物降解、无毒副作用等优点。天然海洋多糖高分子化合物壳聚糖、海藻酸盐作为性能卓越的生物材料已广泛的应用在医学领域。尤其是它们具有良好的生物相容性、生物可降解性、突出的止血效果和抗菌性等特性,对于伤口的愈合有促进作用,是极好的止血材料。本文主要针对这两种海洋高分子化合物作为止血材料的研究进展进行了综述,并对今后的研究重点进行展望。     

Rapid hemostasis and excellent antibacterial cerium-containing mesoporous bioactive glass/chitosan composite sponge for hemostatic material

Rapid and effective hemostasis is key to controlling bleeding and reducing mortality. Here, a composite hemostatic sponge (Ce-MBG/CHT) of cerium-containing mesoporous bioactive glass (Ce-MBG) and chitosan (CHT) was prepared by a freeze-drying technique and compared with the commercially available gelatin sponge (GS), to further evaluate the hemostatic performance of composite sponge materials. The results indicate that the pore structure, porosity, and water absorption of the sponge improved following the addition of Ce-MBG. Whole blood coagulation studies suggested that Ce-MBG/CHT has superior hemostatic properties to GS and validated in vitro thrombosis, platelet adhesion and blood compatibility. In vitro coagulation studies showed that factor XII was activated by the addition of Ce-MBG, inducing the intrinsic coagulation pathway. Furthermore, we evaluated the cytocompatibility of samples after contact with L929 cells for 24, 48, and 72 h via the cytotoxicity test. Compared with GS, 4Ce-MBG/CHT was more efficient against E. coli and S. aureus. All these results indicate that Ce-MBG/CHT sponges are likely useful for rapid hemostasis.     

Hemostasis mechanism and applications of N‐alkylated chitosan sponge

Chitosan (CHI) is a versatile biological material that is well known for its hemostatic properties. This preliminary study evaluated several self‐assembling hydrophobically modified chitosan (HM–CHI) sponges to determine their efficacy on hemostasis . Fourier transform infrared (FT‐IR) spectroscopy was used to determine the successful graft of dodecyl groups onto the nitrogen atoms of CHI molecules. A platelet aggregation assay revealed that HM–CHI accelerated the platelet aggregation rate. Fluorescence spectroscopy showed that the HM–CHI changed the structure of fibrinogen in blood. Activated partial thromboplastin time, prothrombin time, fibrinogen time, and thromboelastographic assays were used to explore the effect of HM–CHI on the autologous blood coagulation pathway. Finally, a hemostatic sponge was made with HM–CHI and freeze‐dried zeolite composite film and was applied to the rat femoral artery hemostasis model. A hemostasis time of 86 ± 5 sec was achieved, which was significantly better than the one composed with pure CHI. The experimental results of the HM–CHI hemostatic materials are inspiring and will encourage the research and development of such materials. HM–CHI may be a strong candidate as a safe and effective hemostatic material. Copyright © 2017 John Wiley & Sons, Ltd.     

Hemostatic efficacy and tissue reaction of oxidized regenerated cellulose hemostats

Oxidized regenerated cellulose (ORC) has been used as an absorbable hemostat since World War II. In the present study, hemostasis time was determined in a spleen incision model in swine. The effect of mass on absorbable hemostat efficacy and hemostasis time was evaluated by standardizing the ORC materials on a mass basis. The median hemostasis time for a single layer of the new nonwoven ORC was as much as 51 % shorter than woven ORC (P < 0.001). The mean hemostasis time for nonwoven ORC was not affected by the mass of hemostat applied to the wound. The hemostatic efficacy of woven ORC increased with the mass (layers) of hemostat applied to the wound. Nonwoven ORC is significantly faster in achieving hemostasis than woven ORC, and its hemostatic efficacy is not influenced by the mass of material applied. Tissue reaction was minimal and the material was fully absorbed by 14 days.     

海藻酸钙多孔微球-白芨多糖复合止血粉的制备及止血性能评价

海藻酸盐具有良好的生物相容性、可降解性、止血、抗菌、促愈合等特性,而中药白芨中的白芨多糖具有收敛止血、消肿生肌的功效。用海藻酸盐和白芨多糖为原料,采用冷冻干燥技术制备海藻酸钙多孔微球-白芨多糖复合止血粉,对其吸水速率进行考核,并采用体外凝血和动物出血模型实验进行止血性能评价。结果表明,致孔剂的添加量为0.5%的海藻酸钙多孔微球,当其与白芨多糖的质量比1:1时制备的止血粉的止血效果最好。     

内镜止血在急性非静脉曲张性上消化道出血治疗中的临床价值

目的在临床当中,对于上消化道当中发生急性、非静脉曲张性出血症状的患者接受治疗的过程当中行以内镜止血方式所起到的效果进行探究。方法随机选取在2015年3月到2016年3月期间于九江学院附属医院就诊的患有急性、非静脉曲张性的上消化道出血症状的患者100名作为研究对象,依照抽签法将其分成实验组(n=50)和参照组两组(n=50),对参照组行常规性的内科止血干预,对实验组则在此基础之上加以行内镜止血干预。对照两组止血效果并做统计。结果经过干预之后,实验组的成功概率为94%,参照组70%,两组对比存在明显的差异,P0.05;另外,在包括住院时长、停止出血时长、肠鸣音的恢复时长上,实验组都明显短于参照组,P0.05,有统计学上的意义。结论对于上消化道当中发生急性、非静脉曲张性出血症状的患者,在其接受治疗的过程当中行以内镜止血方式,能够获得比较好的止血效果,且恢复速度较快,值得进行推广和使用。     

Hemostatic Ability of Chitosan‐Phosphate Inspired by Coagulation Mechanisms of Platelet Polyphosphates

Hemostatic materials have been studied to minimize bleeding time. Recently, polyphosphate (polyP) have received attention as potential hemostatic compounds, which are released from activated platelets. Long polyP chains are essential to form thick fibrin clots. Herein, chitosan is functionalized by covalently tethering phosphate groups to mimic polyP. It is hypothesized that utilizing a known hemostatic polysaccharide, chitosan, and tethering phosphate groups to mimic polyP's functionality show synergistic effect in hemostasis. Five different phosphorylated chitosan conjugates (Chi‐Ps), s‐Chi‐7P, s‐Chi‐28P, s‐Chi‐74P, is‐Chi‐29P, and is‐Chi‐56P are prepared, where “s” indicates water soluble Chi‐Ps and “is” represents water insoluble Chi‐Ps. Unexpectedly, an important carbon in D‐glucosamine is found, which determines chitosan solubility. Phosphate groups conjugated to C6 carbon resulted in water soluble Chi‐P, but conjugation to C3 group exhibited water insoluble behavior. Hemostasis capability showed a positive correlation with the degree of phosphate conjugations regardless of water solubility of Chi‐P.     

Graphene-based hemostatic sponge

Graphene-based sponge is a novel hemostatic material prepared by chemical cross-link of graphene oxide. It has a fast fluid absorption capacity to quickly absorb blood from wounds, activate clotting pathways, and achieve rapid hemostasis. In addition, graphene-based sponge is also a good platform carrier.It can be prepared by organic cross-linking, compounding with inorganic clay, and adding bioactive factors to enhance coagulation stimulation. By these methods, the hemostatic performance of the...     

A microfluidic approach for measuring capillary pressure in PEMFC gas diffusion layers

A dearth of experimental capillary pressure data limits our understanding and optimization of liquid water transport in PEMFC gas diffusion layers (GDLs). A microfluidic device and method is described for measuring the capillary pressure as a function of liquid water saturation for these thin porous materials with complex, heterogeneous wetting properties. A sample sandwich (hydrophilic membrane–GDL–hydrophobic membrane) is key for probing the entire hydrophilic and hydrophobic pore volume of the GDL during sequential liquid intrusion and gas intrusion experiments. The capillary pressure curves for an as-purchased Toray 090 and two differentially-processed Avcarb P75T GDLs were evaluated; each material displayed highly repeatable, but quantitatively different, room temperature capillary pressure curves that matched qualitative differences in their macroscopic wettability. The measurements show that hysteresis between the liquid intrusion and gas intrusion curves is significant. For example, both the Toray and fully wet-proofed Avcarb GDLs appear hydrophobic during most of the liquid intrusion curve and hydrophilic during most of the gas intrusion curve. The implications of this work for water management, and future device designs and experiments are described.     

Polysaccharide Based Hemostatic Strategy for Ultrarapid Hemostasis

Bleeding complications usually cause significant morbidity and mortality in civilian and military populations. In clinical application, hemostatic sponges, gauzes, hydrogel, and bandages are widely used as the traditional effective hemostatic products for hemorrhage. However, the traditional hemostatic devices or agents cannot meet the requirement for treatment of massive bleeding. Therefore, the excellent hemostatic performance of hemostatic products are of great significance for saving lives. Natural polysaccharides, as the main chemical component, have been widely used in the preparation of hemostasis due to their perfect biocompatibility and biodegradability. Polysaccharide based hemostatic products are available in variety of forms, such as, hydrogel, sponges, gauze and microspheres. The purpose of the present review is to report the research progress on polysaccharide hemostatic products and technology.     

Evaluation and comparison of structurally different cellulose-based hemostatic agents in a rat kidney model

Different topical hemostatic materials are used to achieve effective hemostasis. High hemostatic activity, biocompatibility, bioresorbability, and easy manipulation are to be expected in such a developed product. In the surgical world with these specific requirements, finding a proper hemostatic agent is very difficult. The study compared several materials of various construction properties, which were assessed for structural and related properties by morphological analyses and assessed in vivo for their efficiency and behaviour using a model of rat partial nephrectomy. New sodium salt of carboxymethyl cellulose (CMC) sponge with the lowest porosity and free swell absorptive capacity contained the highest amount of hydroxyl and carboxyl groups. Results revealed that this CMC material in the form of a bioresorbable sponge may ensure the necessary hemostatic effects, while also providing a positive influence on the reaction of the local tissue. The CMC material also needed significantly less time to achieve hemostasis (p?<?0.001). Moreover, the sponge reached satisfactory results in the histopathological evaluation with the lowest destruction score and favorable healing reaction. This modified product proved itself to be a promising bioresorbable hemostat, which, according to its design, matches with its surgical applications. In general, the obtained data elucidated the dependency of the total effect on its structure and composition.

Graphic abstract