水凝胶烧伤敷料研究进展

从烧伤的分类及愈合出发 ,提出了理想烧伤敷料的要求。阐述了各种敷料优点及存在的问题 ,对合成敷料的发展现状特别对薄膜敷料和水凝胶敷料的研究情况作了比较详细的讨论 ,分别对合成高分子水凝胶及天然高分子水凝胶及其应用进行了阐述。最后讨论了合成烧伤敷料的发展方向     

水凝胶在放射损伤救治及辐射防护中的应用研究

水凝胶是一类具有亲水基团，能被水溶胀但不溶于水的具有三维网络结构的高分子聚合物。由于具有良好的生物相容性等多种医学特性，水凝胶已作为一种新型生物医学材料广泛应用于伤口敷料、药物载体、组织支架等多个医学领域。本文仅介绍了水凝胶在放射损伤救治及辐射防护中的应用。     

Injectable conductive collagen/alginate/polypyrrole hydrogels as a biocompatible system for biomedical applications

Recently, Injectable Conducting Hydrogel (ICH) systems have gained much attention for tissue engineering and regenerative medicine. These systems can promote the regeneration of tissues responding to electrical responses. In this study, a novel ICH system was introduced. To achieve this system, firstly, a soluble non-toxic polypyrrole (PPy) synthesized by grafting pyrrole on alginate (Alg) backbone (Alg-graft-PPy), and then, ICH systems were prepared by the given ratios of Alg-graft-PPy, Alg, and collagen (Col). Three different amounts of Col (0.5, 1, and 1.5 mg/ml) were added to the system including Alg-graft-PPy: Alg wt. % with the ratios of 20:80 and 30:70. FTIR spectroscopy, electrical conductivity, viscosity, syringeability, gelation time, and MTT assay were performed in order to characterize the produced hydrogels. Due to the rheological behavior of 20:80 (Alg-graft-PPy: Alg wt. %), it was recognized more suitable to inject. Also this system associated with 0.5 mg/ml Col introduced as the best sample with respect to its viscosity and injectability. This ICH system has shown high conductivity in addition to a good level of cell viability and syringeability. With respect to properties of the produced ICH system, it can be applied for bone, nerve, muscle and cardiac cells, which respond to electrical impulses.     

三氯生水凝胶乳化抗菌剂在兔膝损伤模型血液内药动学的对比实验

目的 通过对比分析4种三氯生水凝胶乳剂， 比较给予不同乳剂后兔血液中的三氯生水平和空腹血糖变化的差异. 方法 取同窝新西兰大耳白兔30只(雌雄各15只)，随机分为5组，每组6只(雌雄各3只). 把三氯生(对照组)、三氯生玻璃酸凝胶(玻璃酸组)、三氯生几丁糖凝胶(几丁糖组)及三氯生聚合水凝胶(聚合水凝胶组)4种乳剂，分别在兔损伤膝关节腔内注射，在6，12，24，48，72，96 h抽取血液2 mL，进行高效液相色谱分析，计算血液三氯生浓度;各组于给药前，给药后24，48，72，96 h在左耳静脉反复取血2 mL，测空腹血糖.比较4种乳剂关节腔注射后，与不注射乳剂比较，空腹血糖变化的差异. 结果 各组血液内均检测到三氯生，对照组和聚合水凝胶组的维持时间短于玻璃酸组和几丁糖组.对照组三氯生峰浓度和平均浓度均显著高于其他各组(P<0.05).玻璃酸组三氯生水平显著低于几丁糖组和聚合水凝胶组(P<0.05)，聚合水凝胶组三氯生水平最高(P<0.05). 对照组和聚合水凝胶组的空腹血糖升高和降低最大值均比玻璃酸组和几丁糖组高(均P<0.05). 结论 体内实验表明，①与三氯生乳剂和三氯生聚合水凝胶乳剂比较，三氯生玻璃酸乳剂和三氯生几丁糖乳剂血中三氯生平均浓度较低，空腹血糖水平无明显异常.②三氯生玻璃酸乳剂和三氯生几丁糖乳剂比较，血液药物浓度水平更低，空腹血糖水平无明显异常.因此，三氯生玻璃酸乳剂更适于临床应用.     

Combined Skin Moisturization of Liposomal Serine Incorporated in Hydrogels Prepared with Carbopol ETD 2020, Rhesperse RM 100 and Hyaluronic Acid

We investigated the combined moisturizing effect of liposomal serine and a cosmeceutical base selected in this study. Serine is a major amino acid consisting of natural moisturizing factors and keratin, and the hydroxyl group of serine can actively interact with water molecules. Therefore, we hypothesized that serine efficiently delivered to the stratum corneum (SC) of the skin would enhance the moisturizing capability of the skin. We prepared four different cosmeceutical bases (hydrogel, oil-in-water (O/W) essence, O/W cream, and water-in-oil (W/O) cream); their moisturizing abilities were then assessed using a Corneometer®. The hydrogel was selected as the optimum base for skin moisturization based on the area under the moisture content change-time curves (AUMCC) values used as a parameter for the water hold capacity of the skin. Liposomal serine prepared by a reverse-phase evaporation method was then incorporated in the hydrogel. The liposomal serine-incorporated hydrogel (serine level=1%) showed an approximately 1.62~1.77 times greater moisturizing effect on the skin than those of hydrogel, hydrogel with serine (1%), and hydrogel with blank liposome. However, the AUMCC values were not dependent on the level of serine in liposomal serine-loaded hydrogels. Together, the delivery of serine to the SC of the skin is a promising strategy for moisturizing the skin. This study is expected to be an important step in developing highly effective moisturizing cosmeceutical products.     

The host response to naturally-derived extracellular matrix biomaterials

Biomaterials based on natural materials including decellularized tissues and tissue-derived hydrogels are becoming more widely used for clinical applications. Because of their native composition and structure, these biomaterials induce a distinct form of the foreign body response that differs from that of non-native biomaterials. Differences include direct interactions with cells via preserved moieties as well as the ability to undergo remodeling. Moreover, these biomaterials could elicit adaptive immune responses due to the presence of modified native molecules. Therefore, these biomaterials present unique challenges in terms of understanding the progression of the foreign body response. This review covers this response to natural materials including natural polymers, decellularized tissues, cell-derived matrix, tissue derived hydrogels, and biohybrid materials. With the expansion of the fields of regenerative medicine and tissue engineering, the current repertoire of biomaterials has also expanded and requires continuous investigation of the responses they elicit.     

Diels–Alder hydrogels with enhanced stability: First step toward controlled release of bevacizumab

Eight-armed PEG was functionalized with furyl and maleimide groups (8armPEG20k-Fur and 8armPEG20k-Mal); degradable hydrogels were obtained by cross-linking via Diels–Alder chemistry. To increase the stability to degradation, the macromonomers were modified by introducing a hydrophobic 6-aminohexanoic acid spacer between PEG and the reactive end-groups (8armPEG20k-Ahx-Fur and 8armPEG20k-Ahx-Mal). In an alternative approach, the number of reactive groups per macromonomer was increased by branching the terminal ends of eight-armed PEG with lysine (Lys) and Ahx residues (8armPEG20k-Lys-Ahx-Fur₂ and 8armPEG20k-Lys-Ahx-Mal₂). The hydrolytic resistance of the synthesized macromonomers was determined by UV spectroscopy; the obtained hydrogels were characterized by rheology and degradation studies. The degradation time of 5% (w/v) 8armPEG20k-Ahx hydrogels (28 days) was twice as long as the degradation time of 5% (w/v) 8armPEG20k hydrogels (14 days); this is explained by increased hydrolytic resistance of the maleimide group. Using dendritic 8armPEG20k-Lys-Ahx macromonomers substantially increased the stability of the resulting hydrogels; degradation of 5% (w/v) 8armPEG20k-Lys-Ahx hydrogels occurred after 34 weeks. 8armPEG20k hydrogels had the largest mesh size of all tested hydrogels, while hydrogels made from dendritic 8armPEG20k-Lys-Ahx macromonomers showed the smallest value. To evaluate their potential for the controlled release of therapeutic antibodies, the hydrogels were loaded with bevacizumab. The incorporated bevacizumab was released over 10 days (8armPEG20k) and 42 days (8armPEG20k-Ahx), respectively; release from 8armPEG20k-Lys-Ahx hydrogels was not completed after 105 days. In summary, we believe that 8armPEG20k-Ahx or 8armPEG20k-Lys-Ahx hydrogels could serve as controlled release system for therapeutic antibodies such as bevacizumab.     

The Relation Between Swelling Properties and Cross-Linking of Hydrogels Designed for Colon-Specific Drug Delivery

Copolymers of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA)-based hydrogels containing 5% and 10% of a cross-linking agent were studied as drug delivery systems. Terephthalic acid was covalently linked with HEMA, abbreviated as CA (cross-linking agent). Free radical cross-linking copolymerization of HEMA and methacrylic acid (MAA) in three different molar ratios, mixed with a particulate 3, 3-azobis (6-hydroxy benzoic acid) (ABHB) as an azo derivative of 5-aminosalicylic acid with the various ratios CA as cross-linking agent were carried out with using 2, 2, Azobisisobutyronitrile as initiator at the temperature range 60–70°C. The compositions of the cross-linked three-dimensional polymers were determined by FTIR spectroscopy. Glass transition temperature of the network polymers was determined calorimetrically. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing an aqueous buffer solution (pH 7.4 and pH 1) at 37°C. The drug-release profiles indicate that the amount of drug release depends on its degree of swelling and cross-linking.     

瓜耳胶-g-异丙基丙烯酰胺水凝胶中盐酸青藤碱释放性质研究

目的研究接枝共聚物瓜耳胶-g-异丙基丙烯酰胺（GPNA）水凝胶中盐酸青藤碱释放特征。方法采用Franz-Chien扩散池进行凝胶中药物扩散实验。分别考察释放介质温度、离子强度、pH及交联剂含量对凝胶中药物释放的影响。结果温度、pH、交联剂含量、离子强度对药物的释放均有影响；凝胶中药物在0.1mol·L^-1HCl中释放速度明显快于在0.1mol·L^-1 pH 6.8 PBS中释放速率。温度低于聚合物LCST值时，药物释放没有显著性差异；温度高于聚合物的LCST值时，随着水凝聚的收缩，表面“皮层”逐渐形成，凝胶释药减慢。凝胶中药物药物释放随离子强度及交联剂含量的增加而减慢。结论GPNA水凝胶具有明显的温度及pH敏感性，可用作智能给药的药物载体。     

应用水膨胀式微弹簧圈栓塞治疗外伤性颈动脉海绵窦瘘

目的总结水膨胀式微弹簧圈（HydroCoil）栓塞治疗颈动脉海绵窦瘘（CCF）的初步体会，对HydroCoil治疗CCF的有效性作出评价。方法选取我院2006年1月以来应用HydroCoil栓塞系统治疗14例外伤性颈动脉海绵窦瘘（CCF）病人，男9例，女5例，平均26．5岁。脑血管造影显示6例瘘口位于右侧颈内动脉海绵窦段，8例位于左侧颈内动脉海绵窦段。结果14例病人CCF术后均不再显影，患侧颈内动脉通畅，所有病人术前的颅内杂音、突眼和球结膜充血等症状在1周内恢复正常，视力也有不同程度的恢复。8例病人术后获得1—3个月脑血管造影随访，CCF均未见复发。没有神经系统并发症发生。结论血管内介入治疗已经广泛应用于颈动脉海绵窦瘘，可脱球囊栓塞仍为首选方法。当病人不能耐受或不允许闭塞患侧颈内动脉时，可以选用HydroCoil。HydroCoil治疗CCF安全、有效、稳定，颈动脉保持通畅率高，长期临床效果仍有待于进一步研究。