三种水溶性壳聚糖的制备工艺研究

目的 壳聚糖具有优良的生物相容性和生物可降解性,但其亲水性较差难以满足组织工程的需要.为满足组织工程支架材料的需求,对壳聚糖进行羧甲基化改性,以期改善其溶解性能.方法 通过3种不同的方法来摸索3种不同取代位置的羧甲基壳聚糖(CMC)的制备工艺,分别考察了原料比、反应时间、反应温度等影响因素对产物取代度(DS)的影响.结...     

改性壳聚糖类肝素化合物血液相容性研究

选用壳聚糖为原材料，通过改性在其主链上引入-COOH和-SO3H两种基团制备成类肝素化合物。研究反应过程中羧甲基和磺酸基取代度的影响因素及不同取代位置，不同取代度的化合物复钙时间和溶血率。结果表明，壳聚糖类肝素化合物的抗凝血性能是由甲壳糖主链上引入的-COOH和-SO3H两种基团的协同效应产生的，血液相溶性的优劣主要取决于-COOH和-SO3H两者的比例。N—CM，O—SO3H壳聚糖，当N—羧甲基取代度为0．585，O—磺酸基取代度为0．593时其抗凝血性能最优。而N—SO3H，O—CM壳聚糖，当N—磺酸基取代度为0．689，O—羧甲基取代度为0．593时，其血液相溶性最佳。     

不同分子量羧甲基壳聚糖的制备及其对皮肤成纤维细胞和角质形成细胞生长的影响

本实验将高分子量壳聚糖通过酸水解法和氧化法降解成不同分子量,然后将其羧甲基化制备成相应不同分子量的羧甲基壳聚糖。分别以bFGF和EGF为对照,通过显微观察法和MTT细胞计数法研究不同分子量的羧甲基壳聚糖对小鼠皮肤成纤维细胞和人皮肤表皮角质形成细胞形态及细胞生长的影响。实验结果表明:不同分子量的羧甲基壳聚糖在浓度为1～1 000 ppm时对成纤维细胞和表皮角质形成细胞生长均有促进作用,在浓度为100 ppm时促进作用最强;其促进作用随着分子量的减小而增强,分子量为3 KD左右的羧甲基壳聚糖对成纤维细胞和表皮角质形成细胞生长促进作用最为显著,分别与bFGF和EGF促生长作用基本相当。     

羧甲基壳聚糖钙的制备及其性质结构分析(英文)

背景:羧甲基壳聚糖是壳聚糖改性得到的水溶性衍生物,具有多种生物活性,是金属离子的良好配体,可以与Ca2+进行络合配制一种新型生物材料。目的:研究羧甲基壳聚糖钙盐的制备方法,并对其性质结构进行分析。方法:羧甲基壳聚糖与氯化钙溶液反应生成羧甲基壳聚糖与钙的配合物,进行溶解度、羧甲基化度、旋转黏度、钙含量的测定,以及红外光谱、紫外光谱分析。结果与结论:配合物钙含量在15%左右,与羧甲基壳聚糖相比其溶解度、红外光谱和紫外光谱都产生了改变。制备出的羧甲基壳聚糖与Ca2+的配合物,通过一系列性质结构分析,初步证明为一种新型含钙化合物。     

羧甲基壳聚糖作为植入可降解缓释微球辅料的实验研究

羧甲基壳聚糖作为一种高分子材料 ,具有良好的组织相容性和生物可降解性。本实验试图利用羧甲基壳聚糖作为植入环丙沙星微球的缓释辅料 ,并探索这一剂型的制备工艺、结构形态和体外释药特性。首先我们采用乳化交联技术制备微球 ;然后用扫描电子显微镜、红外光谱、及示差热分析等方法研究微球的结构和形态 ;建立体外持续流动释放系统初步检测微球的体外释放特性。实验结果发现 :微球的结构和形态受制备工艺条件如温度、离子强度、搅拌速度等因素的影响 ;一定工艺条件下制备的环丙沙星微球的体外释放时间可达 7d以上 ,释放行为符合 Higuchi方程。因此 ,我们认为 :羧甲基壳聚糖可作为环丙沙星可降解植入微球的缓释辅料 ;乳化交联技术是制备这一微球的有效方法 ,工艺简单、稳定     

水溶性O-羟乙基壳聚糖接枝聚乳酸的制备与表征

目的制备用于组织工程的水溶性O-羟乙基壳聚糖／聚乳酸共聚物纤维复合支架。方法首先采用壳聚糖与环氧乙烷反应制备水溶性O-羟乙基壳聚糖,然后以辛酸亚锡为催化剂,水溶性O-羟乙基壳聚糖为引发剂,采用本体封管聚合法,激发D,L-丙交酯开环聚合制备水溶性O-羟乙基壳聚糖-g-聚乳酸共聚物。分别用X射线衍射、红外光谱、扫描电镜和溶解实验对产物的结构与性能进行分析表征。结果改性后的水溶性O-羟乙基壳聚糖能明显提高溶解性能,降低结晶性能和氢键间的相互作用。结论通过改性,为得到水溶性O-羟乙基壳聚糖／聚乳酸共聚物奠定了有利条件,并且此共聚物具有较好的孔隙率和网状结构,这对作为药物支架是一个很好的应用。此外,改性后的共聚物易溶于一些常用的有机溶剂中,有利于以后在组织工程中进一步应用。     

壳聚糖与甲基丙烯酸羟乙酯接枝聚合反应的研究

为了改善壳聚糖的亲水性，本用硝酸铈铵为氧化还原引发剂，研究了不同聚合反应条件下，壳聚糖接枝甲基丙烯酸羧乙酯（HEMA）的反应规律，研究了反应时间、反应温度、引发剂浓度和单体浓度对接枝聚合反应的影响，得到了最佳反应条件。用元素分析法和红外光谱对产物进行了表征。用元素分析方法对接枝进行定量分析。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性与体内降解研究

对制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性及体内降解情况进行研究,为临床提供实验依据.参照GB/T16886医疗器械生物学评价标准和要求,对纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥进行急性细胞毒性试验、溶血试验、热源试验、急性全身毒性试验及体内植入试验等系列体内外生物学试验研究,以进行有效的生物相容性和安全性评价.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的溶血率小于国家规定的5％,在体外不引起溶血反应;浸提液注入动物体内后无死亡,活动进食正常;无细胞毒性反应;热原试验动物体温升高均在0.7℃以下,3只兔体温升高值的总数＜1.5℃,无致热作用;材料植入体内初期有轻度炎症反应,随植入时间延长逐渐减轻,材料也逐渐降解吸收.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物相容性和降解性能,具有临床开发应用前景.     

羧甲基壳聚糖在口腔组织工程中的应用北大核心

背景:作为天然生物材料壳聚糖的一种衍生物,羧甲基壳聚糖具有独特的水溶性、成膜性、缓释性,在组织工程领域具有广阔的应用前景。目的:综述羧甲基壳聚糖相较于壳聚糖的优势以及在口腔组织再生方面的应用。方法:利用计算机检索PubMed、中国知网数据库相关文献,中文检索词“羧甲基壳聚糖AND组织工程,羧甲基壳聚糖AND口腔医学”,英文检索词“carboxymethyl chitosan AND tissue engineering,carboxymethyl chitosan AND(dentistry OR stomatology)”,检索时限为2006年1月至2021年10月,通过阅读和分析文献进行初步筛选,以排除重复文献和低相关性文献,最终纳入文献51篇进行结果分析。结果与结论:羧甲基壳聚糖作为一种具有良好生物相容性、可降解的无毒材料,在骨组织再生、牙体组织再生、牙周组织再生方面已取得理想的进展。羧甲基壳聚糖相比壳聚糖具有更好的水溶性、成膜性和离子结合性,这极大扩展了其在口腔组织工程的应用。羧甲基壳聚糖单独使用可发挥抗菌效果,促细胞增殖、分化,或是作为支架材料、水凝胶、改性材料与生物活性成分和生长因子联合使用均达到了预期的实验效果。     

丝素蛋白/壳聚糖三维多孔支架的构建及结构表征**

背景：丝素蛋白和壳聚糖均无毒性且具有良好的生物相容性,但是单一成分作为生物支架时都不能满足支架材料的需求。 目的：制备各种不同组分的丝素蛋白及壳聚糖复合支架材料,观察其微观结构及相关性能,筛选出适合成骨细胞生长的理想支架材料。 方法：通过CaCl2∶C2H5OH∶H2O=1∶2∶8(摩尔比)溶解体系溶解、过滤、浓缩提纯,制备出2%的丝素蛋白溶液,壳聚糖溶解于乙酸溶液配制成的3%壳聚糖溶液,将两者以不同的比例相混合,经数次冷冻干燥后,得到成品支架材料。采用电镜观察形貌,计算孔隙率并对支架的结构进行红外、X射线衍射、电子能谱分析观察。 结果与结论：将壳聚糖和丝素蛋白共混后,互为改性,制备出了结构较稳定的支架材料。其中40%丝素蛋白-60%壳聚糖组具有适合成骨细胞生长的较佳孔径,可作为细胞支架的首选配比。 关键词：丝素蛋白;壳聚糖;骨组织工程;支架;生物材料 doi:10.3969/j.issn.1673-8225.2012.12.025     

Novel pH-sensitive chitosan-based hydrogel for encapsulating poorly water-soluble drugs

Carboxymethyl–hexanoyl chitosan (CHC) is an amphiphilic chitosan derivative with excellent swelling ability and water solubility under natural conditions. In this work, the influence of the degree of carboxymethyl and hexanoyl substitution on the pH-sensitive swelling behavior, drug release behavior, and antiadhesion behavior of CHC hydrogels (cross-linked with genipin) were studied. It was found that the pH sensitivity was more pronounced in CHC than in N,O-carboxymethyl chitosan because the hexanoyl group altered the state of water in CHC by inhibiting intermolecular hydrogen bonding. In addition, greater pH sensitivity was observed in samples bearing longer hydrophobic chains (carboxymethyl–palmityl chitosan). Interestingly, when used with ibuprofen (a poorly water-soluble therapeutic agent used here as a model drug), the bursting release of the drug was less prominent in the CHC samples having a high degree of carboxymethyl substitution. The CHC hydrogel also demonstrated good cell compatibility and its antiadhesive ability after grafting was altered by changes in the degree of hexanoyl substitution.     

Chitosan-RGDSGGC conjugate as a scaffold material for musculoskeletal tissue engineering

In the present study, we have developed a novel and versatile method for the preparation of chitosan-peptide complex based on the selective reaction of chitosan with 2-iminothiolane. The new type of SH-chitosan derivative showed an excellent solubility to aqueous solution even in the alkaline conditions. This characteristic greatly facilitated further modification study of chitosan with a variety of bioactive substances. A synthetic peptide, RGDSGGC containing RGDS moiety that is known as one of the most important cell adhesive peptides, was readily coupled by disulfide bonds formation with sulfhydryl groups of SH-chitosan in the presence of dimethyl sulfoxide. Next, the effect of the introduction of RGDSGGC moiety to chitosan on cell adhesion and proliferation activity of chondrocytes and fibroblasts were evaluated. As a result, it was suggested that this polysaccharide-peptide conjugate exhibited excellent capacities for both cell adhesion and cell proliferation of chondrocytes and fibroblasts. Considering the growing importance of the biocompatible scaffolds in the recent tailored tissue engineering technique, these results indicate that the present strategy of 2-iminothiolane-based conjugation of polysaccharides with biologically active peptides will become a key and potential technology to develop desirable scaffold materials for the tissue regenerations.     

新型关节炎注射液-羧甲基壳聚糖的研究

利用壳聚糖分子 C6 位上羟基与氯乙酸反应制得了水溶性羧甲基壳聚糖 (O- CMC) ,电导法测定羧甲基的取代度为 0 .76。对其进行了溶解性表征及动物造模试验。试验结果表明 O- CMC具有润滑关节 ,有效抑制兔膝关节内成纤维细胞增殖的作用 ,有利于病理性关节软骨的修复 ,对兔类风湿性关节炎有较好的疗效     

Novel injectable biodegradable glycol chitosan-based hydrogels crosslinked by Michael-type addition reaction with oligo(acryloyl carbonate)-b-poly(ethylene glycol)-b-oligo(acryloyl carbonate) copolymers

Novel injectable biodegradable glycol chitosan hydrogels were developed based on thiolated glycol chitosan (GC-SH) and water soluble oligo(acryloyl carbonate)-b-poly(ethylene glycol)-b-oligo(acryloyl carbonate) (OAC-PEG-OAC) triblock copolymers via Michael-type addition reaction. The rheology measurements showed that robust hydrogels were formed rapidly upon mixing aqueous solutions of GC-SH and OAC-PEG-OAC at remarkably low total polymer concentrations of 1.5-4.5 wt % under physiological conditions. The gelation times (varying from 10 s to 17 min) and storage moduli (100 to 4300 Pa) of hydrogels could be controlled by degrees of substitution (DS) of GC-SH, solution pH, and polymer concentration. These glycol chitosan hydrogels had microporous structures, low swelling and slow hydrolytic degradation (stable for over 6 months) under physiological conditions. Notably, these hydrogels were prone to enzymatic degradation with lysozyme. The multiple acryloyl functional groups of OAC-PEG-OAC allowed facile conjugation with thiol-containing biomolecules prior to gelation endowing hydrogels with specific bioactivity. The preliminary cell culture studies revealed that these glycol chitosan hydrogels were cell non-adhesive while Gly-Arg-Gly-Asp-Cys (GRGDC) peptide modified hydrogels could well support adhesion and growth of both MG63 osteoblast and L929 fibroblast cells. These rapidly in situ forming enzymatically biodegradable hybrid hydrogels have great potentials in the development of injectable cell-specific bioactive extracellular matrices for tissue engineering.     

Modulation of the proliferation and matrix synthesis of chondrocytes by dynamic compression on genipin-crosslinked chitosan/collagen scaffolds

Dynamic compression is an important physical stimulus for the physiology of chondrocyte and articular cartilage tissue engineering. In this study, modulation of chondrocyte behaviors in chitosan/collagen scaffolds with different mechanical properties under free-swelling or dynamic compression conditions was investigated. Rabbit chondrocytes were seeded in chitosan/collagen scaffolds crosslinked by genipin (GP) with different concentrations, and then cultured for 3?days prior to cyclic compression of 40% strain, 0.1?Hz, and 30?min/day for 2?weeks. The results showed that the cell proliferation was increased with increasing genipin concentrations and dynamic compression. On the other hand, although total glycosaminoglycans (GAGs) deposition was enhanced by dynamic compression under certain conditions, e.g. the GP0.5 chitosan/collagen scaffolds for 1?week of compression culture, normalized GAGs deposition per cell was decreased by dynamic compression. Our results suggest that while several studies suggest that dynamic compression benefits articular cartilage tissue engineering, many factors including scaffold types and compression conditions determine the outcome of dynamic compression culture.     

Effect of chitosan and carboxymethyl chitosan on fibrinogen structure and blood coagulation

Chitosan has numerous biomedical applications such as tissue engineering scaffolds, drug/gene delivery systems, hemostasis materials, antibacterial materials, wound dressing, etc. In any case, chitosan administered in vivo would positively or passively contact or enter blood tissue. In this situation, the interaction of chitosan with blood components is critical to determine the efficacy and safety of the polymer. In this study, the effect of chitosan with different molecular weight and its derivative carboxymethyl chitosan (CMC) on the structure and function of clotting-related proteins was studied. Specifically, the structural and conformational change of fibrinogen, an important clotting protein, was studied by using UV, fluorescence, and circular dichroism spectroscopy, respectively. Further, the impact of chitosan and CMC on the clotting function was evaluated with activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen time (FT), and thromboelastography (TEG) assays. These results showed that, chitosan and fibrinogen can form complex mainly by electrostatic attraction. As a result, the structure and conformation of fibrinogen are altered by chitosan and CMC. Additionally, the presence of chitosan and CMC has little impact on the values of APTT, PT and FT, but causes significant abnormality in the clotting process by changing TEG parameters. These results provide important insight into the molecular basis for the biological response to chitosan and other biopolymers.     

Potential of 3-D tissue constructs engineered from bovine chondrocytes/silk fibroin-chitosan for in vitro cartilage tissue engineering

The use of cell-scaffold constructs is a promising tissue engineering approach to repair cartilage defects and to study cartilaginous tissue formation. In this study, silk fibroin/chitosan blended scaffolds were fabricated and studied for cartilage tissue engineering. Silk fibroin served as a substrate for cell adhesion and proliferation while chitosan has a structure similar to that of glycosaminoglycans, and shows promise for cartilage repair. We compared the formation of cartilaginous tissue in silk fibroin/chitosan blended scaffolds seeded with bovine chondrocytes and cultured in vitro for 2 weeks. The constructs were analyzed for cell viability, histology, extracellular matrix components glycosaminoglycan and collagen types I and II, and biomechanical properties. Silk fibroin/chitosan scaffolds supported cell attachment and growth, and chondrogenic phenotype as indicated by Alcian Blue histochemistry and relative expression of type II versus type I collagen. Glycosaminoglycan and collagen accumulated in all the scaffolds and was highest in the silk fibroin/chitosan (1:1) blended scaffolds. Static and dynamic stiffness at high frequencies was higher in cell-seeded constructs than non-seeded controls. The results suggest that silk/chitosan scaffolds may be a useful alternative to synthetic cell scaffolds for cartilage tissue engineering.     

羧甲基壳聚糖专属性检验方法研究及应用

目的探讨羧甲基壳聚糖的定性鉴别及含量测定的专属性方法。方法本文将红外光谱法、乙酰丙酮法、二硝基水杨酸比色法这三种方法结合起来,从化学结构、特异性显色及含量测定方面对其羧甲基壳聚糖进行特异性鉴别及含量测定研究。结果该方法简单、快速、准确,能广泛用于羧甲基壳聚糖及其制品的检验。结论给后续羧甲基壳聚糖国标或行标的制定提供参考。