明胶文摘

<正> 明胶溶液冷冻干燥后与已醛溶液相旁地置于同一密封容器中,封闭容器中温度为50℃,相对湿度为75%,放置时间5天。发现只有明胶的赖氨酸残基和羟赖氨酸残基下降并裸露于已醛溶液中.几乎所有的ε-氨基被修饰为1-(5-羰基-5-氨戊基)-2-戊基-3,5-二丁吡啶三甲胺乙内酯。已醛处理未使明胶聚合。可以推测,对蛋白质的已醛诱导聚合,其赖氨酸残基的交联并非必需条件。当明胶修饰的程度大于57%时,明胶的溶解度将显著降     

明胶的基团改性及其对明胶性能的影响

<正> 明胶是一种蛋白质,它是由各种氨基酸通过羧基与氨基的相互联接而形成的一种多肽链。明胶多肽链分子结构可描述为(?)NH—CRH—CO(?),其中的R基代表明胶肽链的侧链基团,如烷基、氨基、羧基、胍基、咪唑基、巯基、硫醚基、羟基及吲哚基等,正是这些侧链的功能性基团构成了明胶许多性质的基础。     

明胶文摘

<正> CA 1988,109(17),148100x 己醛蒸汽对明胶进行化学修饰 Kancko,Shigenobu;et al. Nippon Shokuhin Kogyo Gokkaishi,1988,35(4),271-7(日)。明胶溶液冷冻干燥后与己醛溶液相旁地置于同一密封容器中,封闭容器中温度为50℃。相对湿度为75％,放置时间5天。发现只有明胶的赖氨酸残基和羟赖氨酸残基下降并裸露于己醛溶液中。几乎所有的ε-氨基被修饰为1-(5-羰基-5-氨戊基)-2-戊基-3,5-二丁吡啶三甲胺乙内酯。己醛处理未使明胶聚合,可以推     

一种多孔磁性明胶微球及其制备方法

明胶具有良好的生物相容性以及降解性,被广泛应用于生物、医学、化工等领域。在明胶中包埋磁性颗粒制备的磁性明胶微球可用于药物缓释、酶的固定、血管栓塞和靶向给药等。由于明胶的热稳定性差以及遇水易溶胀,通常采用甲醛或者戊二醛等交联剂来固化磁性明胶微球,是利用醛类与明胶分子中赖氨酸或羟基赖氨酸上的氨基进行反应,使微球表面形成较高密度的交联键而固化。     

PA明胶与明胶

<正> 众所周知,明胶是天然胶朊降解得到的一种变性蛋白质,具有许多优异的特性。正因如此,被广泛地应用于感光工业及各行业中作为乳化剂、成膜剂等。由于明胶分子上有许多活性基团如,α、ε-氨基、羧基、羟基、咪唑基等,因而可以通过化学改性以调变明胶分子的性质。PA明胶就是其典型代表之一。 PA明胶即酞酰化明胶。在一定的反应条件下,酞酸酐能与明胶分子上的氨基进行反应。从反应式可看出,酞酰化的结果,明胶上氨基数减少,羧基数增加,从而改变了明胶分子的某些性质。又由于制备条件的影响,也     

改性明胶取代度测定方法介绍

<正> 目前,改性明胶在国外应用已有十年历史,在国内也已在开始应用。在沉降法乳剂制作中,改性明胶沉降剂正在逐步代替树脂沉降剂。它除了应用于乳剂制造外,还可用于医药、洗涤剂等方而。因此,改性明胶的应用范围正在日益扩大。这就需要对改性明胶的制备及其性质进行研究,其中包括改性明胶的取代度的测定。我们将取代度α定义为反应氨基与原始α-氨基及ε-氨基和之比。这里主要介绍文献中两种测定取代度的方法:一种是甲醛滴定法,另一种是水合茚满三酮比色法。     

测定酞酰化明胶取代度所需原胶的研究

<正> 测定酞酰化明胶的取代度通常多采用甲醛滴定法。此方法的优点是简便、快速。其原理是:在pH中性和常温条件下,明胶分子侧链上的氨基酸能很快地与甲醛发生缩合反应,在固定甲醛量不变的情况下,滴定时所消耗的碱量直接当作该明胶改性前原有的和改性后尚存留的氨基数的一个量度。其反应式为: 具体方法是,准确称取1克明胶,置于250ml锥形瓶中,加入100ml蒸馏水,溶胀     

软组织胶原与硬组织胶原的明胶化

<正> 明胶可以定义为水不溶性天然胶原纤维分解、断裂和降解所得到的水溶性产物。所以,明胶化包括了结构破坏或溶化、肽键或交联键水解或断裂和所得到的高分子肽链的分散等这样一些独立的过程。已经育人对酸可溶性胶原和中性盐可溶性胶原的明胶化过程进行过研究,并凡对于可溶性胶原与非可溶性胶原的明胶化过程已提出了完整的见解。为避免在文中以冗长的篇幅来介绍已经完成的有关胶原明胶化转变过程的特性和明胶分子量分布与原胶原结构中交联键分布间     

明胶/壳聚糖共混膜的制备

本文研究了明胶与壳聚糖共混制膜技术,考察了影响交联反应的因素。结果表明,共混体系中明胶和壳聚糖的比例、体系的pH影响较大,而体系的温度的影响不显著;通过对制备得到的明胶-壳聚糖共混膜进行的X-RD证明,明胶和壳聚糖分子间发生了交联反应。     

明胶文摘

<正>果胶一明胶原位交联水凝胶的制备与特征Bhuvanesh G, et al.Carbohydrate Polymers 2014,106:312～318.交联水凝胶是由高碘酸盐氧化果胶(OP)和明胶原位反应制得的。反应通过OP的醇基与明胶的氨基集形成希夫碱而进行。本文对不同的反应参数例如反应时间、反应温度、反应pH值以及构成成分对交联效能的影响进行了研究。通过场发射电子扫描显微镜(FESEM)观察发现在OP和明胶交联反应后,制成了均匀的单相系统。对水凝胶的溶胀性进行了研究并发现平衡溶胀随着明胶含量不同(10%～40%)在195%～324%范围内变     

Biofabrication of Gelatin Tissue Scaffolds with Uniform Pore Size via Microbubble Assembly

The control of pore size and uniform porosity remains as an important challenge in gelatin scaffolds. The precise control in building blocks of tissue scaffolds without any additional porogen is possible with costly equipment and techniques, though some pre‐requirements for polymeric material, such as photo‐polymerizability or sintering ability, may be needed prior to construction. Herein, a method for the fabrication of gelatin scaffolds with homogenous porosity using simple T‐junction microfluidics is described. The size of the microbubbles is precisely controlled with 5% deviation from the average. Porous gelatin scaffolds are obtained by building‐up the monodispersed microbubbles in dilute cross‐linker solutions. The effect of cross‐linker density on pore diameter is also investigated. After cross‐linking, pore size of the resultant five scaffold groups are precisely controlled as 135 ± 11, 193 ± 11, 216 ± 9, 231 ± 5, and 250 ± 12 µm. Porosity ratios above 65% are achieved in every sample group. According to the cell culture experiments, structures support high cell adhesion, viability, and migration through the porous network via interconnectivity. This study offers a practical and economical approach for the preparation of porous gelatin scaffolds with homogenous porosity which can be utilized in diverse tissue engineering applications.     

Biodegradable Laminates Based on Gelatin, 2

Compression moulded laminates based on a gelatin or a blended gelatin/starch matrix reinforced by fabrics (linen or silk) were prepared. Three linen or five silk sheets with a powdered matrix between them were compression moulded at 180 °C for several minutes. In addition, cross‐linked laminates were obtained by using methylenedi(p‐phenyl) diisocyanate as a cross‐linking agent expected to obtain an improved integrity between the matrix and the reinforcing elements. In this way a total of ten uncross‐linked and cross‐linked samples differing in the type of the matrix (gelatin or gelatin/starch) and the type of the reinforcing element (linen or silk), both uncross‐linked and cross‐linked, were obtained. All samples were characterized by means of mechanical testing (Young's modulus, tensile strength, elongation at break and impact strength), as reported in Part 1 of this study. In the present Part 2, the same ten samples were artificially weathered, and changes in both the mechanical properties and the specific wear rate with aging time were followed. It was found that the majority of the mechanical parameters generally became worse with aging time; only the Young's modulus and the tensile strength remained on the same order of magnitude for all laminates. The linen reinforced laminates showed much higher values of the deformation at break, the impact strength and the wear resistance in comparison to the silk reinforced laminates. A similar tendency was found for the sliding wear tests against smooth steel counterparts. A reinforcement of gelatin or gelatin/starch with linen was much more effective in improving the laminate wear resistance than a reinforcement with silk. In addition, the abrasion resistance of neat gelatin was found to be much higher than that of the gelatin/starch blend, as evaluated by the Taber index.

Dependence of Young's modulus on aging time for the neat matrix samples (gelatin and gelatin/starch) and the compression moulded laminates reinforced with fabrics.     

重组人骨形态发生蛋白-7复合体对牙槽骨再生的影响

目的观察基因重组人骨形态发生蛋白-7(rhBMP-7)与明胶海绵的复合体对犬牙槽骨再生的影响。方法犬拔牙创内植入rhBMP-7与明胶海绵的复合体,以自然愈合拔牙创为对照。于术后2、4、8周分别将犬处死,取拔牙创处牙槽骨标本,行X线和组织学切片检查,观察成骨情况及牙槽骨萎缩情况。结果X线及组织学切片显示实验侧成骨速度及成骨质量明显优于对照侧。结论rhBMP-7与明胶海绵复合体是一种可促进牙槽骨再生的新型生物复合材料。     

重组人骨形态发生蛋白-7活性检测方法的建立

目的建立一种新的重组人骨形态发生蛋白-7(Recombinant human bone morphogenetic protein-7,rhBMP-7)活性检测方法。方法将吸收性明胶海绵与rhBMP-7混匀,冻干,环氧乙烷灭菌后,植入小鼠大腿股部肌间隙,共设5组:明胶海绵对照组及50、100、150、250μg rhBMP-7/块明胶海绵实验组,分别于术后第2、3周取材,进行HE染色及蛋白含量测定。结果 HE染色结果显示,与明胶海绵对照组相比,rhBMP-7/明胶海绵组细胞数量明显增多,且随着rhBMP-7剂量的增加及作用时间的延长而逐渐增多。蛋白含量测定结果显示,与明胶海绵对照组相比,rhBMP-7/明胶海绵组蛋白含量随着rhBMP-7剂量的增加及作用时间的延长而逐渐增加,且rhBMP-7剂量与每组蛋白含量平均值呈良好的相关性。结论将rhBMP-7复合明胶海绵植入小鼠大腿肌间隙并于第2周取材进行蛋白含量测定的方法,可用于rhBMP-7活性检测。     

固定化酶膜中凝胶层膜的制备与性能研究

以高性能杂萘联苯聚醚砜酮（PPESK）中空纤维超滤膜为底膜制备了酶膜反应器,采用改进后的Newel法制备凝胶层膜,比较了鞣制过程中静态法与动态法的优劣,考察了明胶涂敷、交联剂浓度、鞣制温度对凝胶层膜性能的影响,并探讨了凝胶层膜的清洗与再生条件。结果表明,以质量浓度为10g／L,过滤时间为30min的明胶,质量分数为2％、温度为35℃的戊二醛溶液为交联剂动态鞣制凝胶层膜为最佳实验条件,并且以酸洗和碱洗相结合的方法清洗再生凝胶层膜,效果良好。     

Gelatin hydrogels with PAMAM nanostructured surface and high density surface-localized amino groups

Amino-terminated PAMAM dendrimers with 16 and respectively 64 amino groups have been chemically immobilized onto the surface of glutaraldehyde (abbreviated GA) crosslinked thin gelatin scaffolds based on Schiff-base linkage formation between the amines and free aldehyde from partially unreacted GA. Crosslinking and dendrimers surface modification of hydrogels have been chemically and physically investigated using FT-IR spectroscopy and microscopy, UV–VIS, LM, AFM, swelling tests and a colorimetric technique. Two types of gelatin-based hydrogels with homogeneous nanorough surfaces and presenting an increased number of amino groups available for further chemical reactions have been obtained. The synthesis strategy presented in this work seems to open a new route for nanorough crosslinked gelatin scaffolds that could be further used for biomedical and especially for hard tissue engineering application.     

The Role of Bloom Index of Gelatin on the Interaction with Retinal Pigment Epithelial Cells

Biocompatible materials are of considerable interest in the development of cell/drug delivery carriers for therapeutic applications. This paper investigates the effects of the Bloom index of gelatin on its interaction with retinal pigment epithelial (RPE) cells. Following two days of culture of ARPE-19 cells with gelatin samples G75-100, G175, and G300, the in vitro biocompatibility was determined by cell proliferation and viability assays, and glutamate uptake measurements, as well as cytokine expression analyses. The mitochondrial dehydrogenase activity in the G300 groups was significantly lower than that of G75-100 and G175 groups. The Live/Dead assays also showed that the gelatin samples G300 induced mild cytotoxicity. In comparison with the treatment of gelatins with low Bloom index, the exposure to high Bloom strength gelatins markedly reduced the glutamate uptake capacity of ARPE-19 cells. One possible explanation for these observations is that the presence of gelatin samples G300 with high viscosity in the medium may affect the nutrient availability to cultured cells. The analyses of pro-inflammatory cytokine IL-6 expression at both mRNA and protein levels showed that the gelatins with low Bloom index caused less cellular inflammatory reaction and had more acceptable biocompatibility than their high Bloom strength counterparts. These findings suggest that the Bloom index gives influence on cellular responses to gelatin materials.     

鱼明胶的功能特性与应用

明胶是一种由传统哺乳类动物产品,肉类加工副产品制得的部分水解蛋白。由于其独特的功能性质和合理的价格而在食品和医疗行业中广泛应用。因为安全、经济、宗教和其他原因,来源于鱼类加工下脚料的鱼明胶成为新的明胶替代材料。文章就鱼明胶的制备方法、风味和冻力、黏度、乳化性、起泡性、成膜性等功能性质进行介绍。另外,对其在食品、医药和其他行业的应用进行总结,目的是为进一步开发利用鱼明胶提供一定的理论依据。     

交联壳聚糖树脂制备与吸附低浓度盐酸的研究

通过壳聚糖与铜离子作用得到模板壳聚糖，再用交联剂环氧氯丙烷交联后将铜离子洗脱制得交联壳聚糖树脂，研究了不同交联度的交联壳聚糖树脂的物理特性与吸附低浓度盐酸的特性。     

明胶多孔支架固定化过氧化氢酶

以明胶多孔支架为载体,戊二醛为交联剂成功地制备了固定化过氧化氢酶,并对其固定化酶的性质进行了研究。固定化过氧化氢酶活力回收率可高达51.1%。与游离酶相比较,虽然催化效率有所降低,但是其固定化酶在65℃保存的稳定性有明显提高。固定化酶可重复使用10次后,活力仍保持在初始活力的60%以上,其具有良好的操作稳定性。