壳聚糖-透明质酸共混膜性质的研究

以溶液共混法制成不同比例的壳聚糖一透明质酸共混膜,通过观察各种共混膜的表面形态结构、结晶度、透光率等,发现在以较低比例混入透明质酸所形成的共混膜中两种高分子的相容性较好,分子间存在较强的相互作用力,形成的共混膜表面结构均匀单一。通过对共混膜理化性质的研究,发现透明质酸的混入可以有效的改变壳聚糖膜的力学特性、吸水性、吸附性以及对小分子物质的渗透性。以共混膜和壳聚糖膜为载体培养兔角膜细胞,结果发现较低比例的透明质酸可以显著提高壳聚糖膜与角膜细胞的相容性,能够有效的支持细胞在膜上生长,结果提示以一定共混比例制成的壳聚糖一透明质酸共混膜可以作为细胞体外培养的良好载体,可用于器官损伤修复以及细胞移植。     

壳聚糖/聚乙烯醇共混膜的结构表征及性能研究

由壳聚糖和聚乙烯醇的醋酸水溶液共混,流延成膜,然后用1mol/L的NaOH水溶液处理,成功制得具有互穿网络结构的壳聚糖/聚乙烯醇二元共混膜.采用红外光谱、X射线衍射和扫描电镜对共混膜进行了结构表征,并对共混膜的透光率、吸水率、保水率、力学性能、透水汽率、热稳定性等方面进行了测试.结果表明,共混膜中壳聚糖与聚乙烯醇具有良好的相容性,其中壳聚糖与聚乙烯醇分子间的作用力使共混膜理化性能得到了显著改善.     

柞蚕丝素/壳聚糖共混膜的结构及细胞相容性

用碳化二亚胺(EDC)作为交联剂,流延法制备柞蚕丝素(ASF)/壳聚糖(CS)共混膜。用扫描电镜(SEM)、红外光谱(FT-IR)、热重分析(TG)和四甲基偶氮唑盐比色法(MTT)对膜的结构及细胞相容性进行了研究。结果显示,柞蚕丝素和壳聚糖具有较好的相容性和较强的相互作用,壳聚糖能阻碍共混膜内的丝素蛋白形成β-折叠构象。EDC能分别与柞蚕丝素及壳聚糖反应,从而对共混膜进行有效的交联,并使膜的热稳定性提高。与ASF膜或CS膜相比,共混比为80/20和40/60的ASF/CS共混膜更有利于细胞生长和增殖,作为一种新型的生物材料具有良好的研究和开发应用前景。     

角膜内皮细胞载体壳聚糖基共混膜的制备及性质研究

为探讨壳聚糖基共混膜作为组织工程化角膜内皮细胞载体的可行性,制备了羟乙基壳聚糖/明胶/硫酸软骨素共混膜,并评价其性质。结果表明该膜片具有良好的透明度,适宜的含水量;细胞毒性0～1级;体外培养的角膜内皮细胞能够很好地贴附和生长于共混膜上;植入大鼠肌肉内,能够稳定地降解,诱发的炎症反应明显低于不可降解手术缝合线,说明该膜片具有良好的组织相容性,有望作为角膜细胞载体构建组织工程化角膜。     

壳聚糖-硫酸软骨素共混膜与兔角膜基质细胞相容性的研究

为了探讨硫酸软骨素对壳聚糖膜与兔角膜基质细胞相容性的影响,在制备了不同壳聚糖-硫酸软骨素共混膜的基础上,以壳聚糖-硫酸软骨素共混膜作为载体培养兔角膜基质细胞,研究兔角膜基质细胞在共混膜上贴附、生长和代谢的情况,并观察了细胞的形态结构.结果发现,硫酸软骨素的混入可以有效地提高兔角膜基质细胞在膜上的贴附和生长速度,促进蛋白质的代谢,降低共混膜对细胞的损伤,有利于细胞在膜上长成密集单层,预示了以一定比例混入硫酸软骨素可以显著提高壳聚糖膜与兔角膜基质细胞的相容性,壳聚糖-硫酸软骨素共混膜具有作为兔角膜基质细胞培养和移植载体的潜能.     

壳聚糖-聚己内酯复合膜的制备及其性能研究

为综合壳聚糖(CS)和聚己内酯(PCL)的性能,将CS和PCL在醋酸溶液中进行共混,利用流延法制备5/95,10/90,15/85,20/80 4种不同比例的壳聚糖-聚己内酯复合膜.采用元素分析、FTIR、XRD和SEM对膜的组分、结构和形貌进行了表征,证明了壳聚糖和聚己内酯在复合膜中有一定的相容性.探讨了体系中壳聚糖含量对多孔膜的力学性能和吸水率、溶胀比、孔隙率的影响,结果表明:在实验范围内随壳聚糖含量的增加,复合膜的刚度从4 188.17N/m提高到20 436.00 N/m;杨氏模量亦从30.52 MPa增加到69.69 MPa;断裂伸长率降低.吸水率可达76.39%,孔隙率亦可增加到约35%,而溶胀比几乎不变.     

明胶固定化壳聚糖膜的细胞相容性评价

用碳二亚胺将明胶固定于壳聚糖膜表面,以改善壳聚糖的细胞相容性.采用MTT法评价膜材料对L929细胞的毒性.将壳聚糖膜(CS)、明胶固定化壳聚糖膜(CS-GEL)与人角膜上皮细胞(HCEC)体外复合培养,观察细胞的形态及生长情况,考察材料的细胞粘附率、材料对细胞活性与增殖的影响,并通过流式细胞术对细胞周期和凋亡进行分析.结果表明,CS-GEL具有良好的细胞粘附性,HCEC在CS-GEL上的生长和增殖情况优于CS,与CS相比,CS-GEL上HCEC的G1期比例下降,S期和G2期增加.明胶的引入缩短了细胞在膜表面的适应时间,使其尽快进入正常的细胞周期;同时表面固定的明胶可抑制细胞凋亡.因此,明胶固定化壳聚糖膜具有良好的体外细胞相容性,有望成为一种较好的角膜修复材料.     

明胶-壳聚糖合金膜的制备及表征

采用水溶液共混法制备了明胶-壳聚糖合金膜,添加了醋酸氯己啶为抑菌剂,1-乙基-3-(3-二甲氨丙基)碳化二亚胺盐酸盐为交联剂.通过IR、DSC和UV对合金膜进行了表征,证明了明胶、壳聚糖和醋酸氯己啶在合金膜中有很好的相容性.研究了体系中醋酸氯己啶含量和交联剂用量对合金膜吸水率、溶胀比和孔隙率等性能的影响.结果表明,在实验范围内随醋酸氯己啶含量的增加,膜的吸水率和孔隙率逐渐下降,而溶胀比变化不大;随交联剂量增加,膜的孔隙率增大,而溶胀比和吸水率基本不变.抑菌实验表明,醋酸氯己啶的加入提高了膜的抑菌性能.     

淀粉/PVA膜在血浆模拟液及唾液模拟液中的体外降解行为及相关体外生物相容性评价

通过熔融浇注法制备出一系列厚度在0.05 mm～0.10 mm的淀粉/聚乙烯醇（PVA）（SP）薄膜。研究了薄膜在血浆（SBF）及唾液模拟液（SSF）中的降解行为,分析了降解过程中力学性能、失重率、溶胀度、热性能以及表面形态的变化。研究结果表明,膜在30天的降解过程中能够维持良好的尺寸稳定性和一定的力学强度。通过细胞毒性、细胞贴壁及溶血试验表征了膜的体外生物相容性。结果表明,SP膜具有良好的细胞和血液相容性。所有测试结果证明,SP薄膜是一种应用于诱导组织再生薄膜的潜在材料。      

胶原蛋白-葡甘聚糖-壳聚糖(CKCS)共混膜的生物相容性研究

通过内皮细胞-膜复合物的培养、组织学观察和MTT法对细胞增殖的测定以及动态凝血实验、溶血实验和复钙实验考察了胶原蛋白-葡甘聚糖-壳聚糖(CKCS)共混膜的细胞相容性和血液相容性,为共混膜在生物医学领域的应用提供理论依据.     

Biodegradation and compressive strength of phosphorylated chitosan/chitosan/hydroxyapatite bio-composites

The research about how to obtain an organic/inorganic bio-composite with excellent comprehensive properties is an active research field. Nowadays, very few of the achievements were applied to the clinical use due to many reasons. In this work, the purpose was to get a three-phase composite with good compressive strength by using phosphorylated chitosan. Phosphorylated modification of chitosan would bring new properties such as metal chelating. Four phosphorylated chitosan/chitosan/hydroxyapatite (PCS/CS/HA) composites with the weight ratios of 40/40/20, 30/30/40, 20/20/60, 10/10/80 were prepared through the coprecipitation method. The maximum value of compressive strength was measured about 70.25 MPa corresponding to the PCS/CS/HA composite rod with a weight ratio of 30/30/40. The composite rod maintained 64% of original compressive strength after soaking in simulated body fluid for 20 days. All the results showed that the PCS/CS/HA composite (30/30/40), had a good compressive strength, was appropriate to be used as a novel bio-composite for bone tissue engineering.     

Electrospun chitosan/PEDOT nanofibers

Plasma-modified chitosan and poly(3,4-ethylenedioxythiophene) were blended to obtain conducting nanofibers with polyvinyl alcohol as a supporting polymer at various volumetric ratios by electrospinning method. Chemical compositions and molecular interactions among nanofiber blend components were determined using Fourier transform infrared spectroscopy (FTIR). The conducting blends containing plasma-modified chitosan resulted in a superior antibacterial activity and thinner fiber formation than those containing chitosan without plasma-modification. The obtained nanofiber diameters of plasma-modified chitosan were in the range of 170 to 200 nm and those obtained from unmodified chitosan were in the range of 190 to 246 nm. The electrical and electrochemical properties of nanofibers were also investigated by four-point probe conductivity and cyclic voltammetry measurements.     

聚己内酯改性壳聚糖/壳寡糖生物材料的研究进展

综述了近年来国内外聚己内酯接枝改性壳聚糖生物材料的制备方法及在组织工程和药物释放载体方面的应用。此外,还对聚己内酯接枝改性壳寡糖的研究进展及应用前景进行了展望。     

超顺磁性羟基磷灰石/壳聚糖棒材的制备

以壳聚糖膜为模板将磁性羟基磷灰石前驱体的壳聚糖醋酸溶液与NaOH凝固液隔离,OH^-向磁性羟基磷灰石前驱体的壳聚糖醋酸溶液内部的渗透引起pH值变化,导致质子化的壳聚糖在模板上沉积的同时无机物就地生成,原位复合制备出无机纳米颗粒分散均匀的磁性羟基磷灰石／壳聚糖（HA／CS）复合棒材．生成的超顺磁性四氧化三铁和羟基磷灰石颗粒大小均一（大约长30nm,宽20nm）,在基质中分布均匀、没有出现明显的团聚现象．     

原位增强羟基磷灰石/壳聚糖复合棒材

利用低温水溶液均相沉积法制备了磷酸钙盐微纤维; 应用原位沉析法制备了壳聚糖(CS)三维棒材及羟基磷灰石(HA*)/CS复合棒材。XRD证实应用原位沉析法制备HA*/CS复合棒材过程中, 磷酸钙盐转化为羟基磷灰石结构, 尺寸为10~60 μm, 并用SEM对晶体形貌进行了表征, 分析了转化机制。HA*/CS复合材料的微观形貌表明, HA*晶体在CS凝胶棒原位沉析的过程中析出而与CS基体形成镶嵌、 相互咬合结构, 且在基体中分散均匀, 有效地提高了HA*与CS基体的界面连接作用, 使力学性能显著提高。所制备的HA*/CS棒材随HA*含量的增大(在其饱和溶解度3.3 wt%范围内), 复合材料的弯曲性能逐渐提高, 当羟基磷灰石质量分数为3.3%时, 复合材料的弯曲强度达到159.6 MPa, 弯曲模量达到5.1 GPa, 比CS基体分别提高85.6%和54.5%。HA*/CS复合棒材的弯曲强度和弯曲模量远高于松质骨, 弯曲强度也比密质骨高。      

银基蒙脱土/壳聚糖的制备及性能

为了在改善壳聚糖(CS)抑菌性能的同时提高其强度, 将银基蒙脱土(Ag-MMT)在CS的醋酸溶液中通过溶液插层法制备了银基蒙脱土/壳聚糖(Ag-MMT/CS)。在模拟体液环境中测得的银离子释放性能显示Ag-MMT/CS中的银离子可以达到平稳缓慢释放; 通过最小抑菌圈法对Ag-MMT/CS进行抑菌性能测试, 结果表明, Ag-MMT/CS对金黄色葡萄球菌有良好的抑菌效果, 抑菌圈直径可达9.2 mm, 比CS增大50.6%, 抑菌率测试结果显示蒙脱土的加入有助于吸附并杀死更多的细菌; 动态热机械分析(DMA)测试结果显示, Ag-MMT/CS的储能模量最高可达3261 MPa, 比CS提高195%, 显示出良好的动态力学性能。     

银基蒙脱土/壳聚糖的制备及性能

为了在改善壳聚糖(CS)抑菌性能的同时提高其强度,将银基蒙脱土(Ag-MMT)在CS的醋酸溶液中通过溶液插层法制备了银基蒙脱土/壳聚糖(Ag-MMT/CS).在模拟体液环境中测得的银离子释放性能显示Ag-MMT/CS中的银离子可以达到平稳缓慢释放;通过最小抑菌圈法对Ag-MMT/CS进行抑菌性能测试,结果表明,Ag-MMT/CS对金黄色葡萄球菌有良好的抑菌效果,抑菌圈直径可达9.2mm,比CS增大50.6％,抑菌率测试结果显示蒙脱土的加入有助于吸附并杀死更多的细菌;动态热机械分析(DMA)测试结果显示,Ag-MMT/CS的储能模量最高可达3261MPa,比CS提高195％,显示出良好的动态力学性能.     

Effect of hydroxyapatite nanoparticles on ibuprofen release from carboxymethyl-hexanoyl chitosan/O-hexanoyl chitosan hydrogel

In order to explore the effect of nanofiller on the regulation of the drug release behavior from microsphere-embedded hydrogel prepared by carboxymethyl-hexanoyl chitosan (HNOCC) and O-hexanoyl chitosan (OHC), the release kinetics was investigated in terms of various amounts of calcium-deficient hydroxyapatite (CDHA) nanoparticles incorporated. HNOCC is a novel chitosan-based hydrophilic matrix with a burst release profile in a highly swollen state. The drug release kinetics of the HNOCC hydrogel can be regulated by incorporation of well-dispersed CDHA nanoparticles. It was found that the release duration of ibuprofen (IBU) from HNOCC was prolonged with increasing amounts of CDHA which acts as a crosslink agent and diffusion barrier. On the contrary, the release duration of the IBU from OHC (hydrophobic phase) was shortened through increasing the CDHA amount over 5%, which is due to the hydrophilic nature of the CDHA nanoparticles destroying the intermolecular hydrophobic interaction and accelerating OHC degradation. Thus, water accessibility and molecular relaxation were enhanced, resulting in a higher release rate. In addition, sustained and sequential release behavior was achieved by embedding the OHC microspheres (hydrophobic phase) into the HNOCC (hydrophilic phase) matrix, which could significantly prolong the release duration of the HNOCC drug-loaded implant.     

Preparation and characterization of collagen/PLA,chitosan/PLA,and collagen/chitosan/PLA hybrid scaffolds for cartilage tissue engineering

In this study, three-dimensional (3D) porous scaffolds were developed for the repair of articular cartilage defects. Novel collagen/polylactide (PLA), chitosan/PLA, and collagen/chitosan/PLA hybrid scaffolds were fabricated by combining freeze-dried natural components and synthetic PLA mesh, where the 3D PLA mesh gives mechanical strength, and the natural polymers, collagen and/or chitosan, mimic the natural cartilage tissue environment of chondrocytes. In total, eight scaffold types were studied: four hybrid structures containing collagen and/or chitosan with PLA, and four parallel plain scaffolds with only collagen and/or chitosan. The potential of these types of scaffolds for cartilage tissue engineering applications were determined by the analysis of the microstructure, water uptake, mechanical strength, and the viability and attachment of adult bovine chondrocytes to the scaffolds. The manufacturing method used was found to be applicable for the manufacturing of hybrid scaffolds with highly porous 3D structures. All the hybrid scaffolds showed a highly porous structure with open pores throughout the scaffold. Collagen was found to bind water inside the structure in all collagen-containing scaffolds better than the chitosan-containing scaffolds, and the plain collagen scaffolds had the highest water absorption. The stiffness of the scaffold was improved by the hybrid structure compared to plain scaffolds. The cell viability and attachment was good in all scaffolds, however, the collagen hybrid scaffolds showed the best penetration of cells into the scaffold. Our results show that from the studied scaffolds the collagen/PLA hybrids are the most promising scaffolds from this group for cartilage tissue engineering.     

Effect of enzymatic degradation of chitosan in polyhydroxybutyrate/chitosan/calcium phosphate composites on in vitro osteoblast response

Polyhydroxybutyrate/chitosan/calcium phosphate composites are interesting biomaterials for utilization in regenerative medicine and they may by applied in reconstruction of deeper subchondral defects. Insufficient informations were found in recent papers about the influence of lysozyme degradation of chitosan in calcium phosphate/chitosan based composites on in vitro cytotoxicity and proliferation activity of osteoblasts. The effect of enzymatic chitosan degradation on osteoblasts proliferation was studied on composite films in which the porosity of origin 3D scaffolds was eliminated and the surface texture was modified. The significantly enhanced proliferation activity with faster population growth of osteoblasts were found on enzymatically degraded biopolymer composite films with α-tricalcium phosphate and nanohydroxyapatite. No cytotoxicity of composite films prepared from lysozyme degraded scaffolds containing a large fraction of low molecular weight chitosans (LMWC), was revealed after 10 days of cultivation. Contrary to above in the higher cytotoxicity origin untreated nanohydroxyapatite films and porous composite scaffolds. The results showed that the synergistic effect of surface distribution, morphology of nanohydroxyapatite particles, microtopography and the presence of LMWC due to chitosan degradation in composite films were responsible for compensation of the cytotoxicity of nanohydroxyapatite composite films or porous composite scaffolds.