聚乳酸/壳聚糖多孔支架材料的生物学性能评价

通过过敏试验、热原试验和细胞培养与毒性试验，对聚乳酸(PLA)／壳聚糖多孔支架材料进行了生物学评价。结果显示，聚乳酸／壳聚糖复合三维多孔材料均呈阴性，符合ISO 10993-1标准，细胞能在材料表面更好的贴附和生长。所以，本材料具有良好的生物相容性，可以用作细胞支架材料植入体内。     

左旋聚乳酸的改性实验

背景：目前临床上大量使用的金属支架永久存留于人体,对人体存在潜在的风险。 目的：观察改性对左旋聚乳酸的作用以及改性材料用于可降解支架制备的可行性。 方法：以左旋聚乳酸/聚己内酯为95∶5的比例,用溶液法制备左旋聚乳酸、聚乳酸/聚己内酯共聚材料(PLCL-J 9505)和聚乳酸/聚己内酯共混材料(PLCL-H 9505)薄膜。 结果与结论：力学性能测试结果显示,3个月左旋聚乳酸材料的脆性明显升高,材料变得容易断裂,成为制备支架的一大缺陷;PLCL-J材料力学性能损失过快,第3周屈服完全消失,第4周拉伸强度开始急剧下降,到第10周已经完全丧失力学性能;PLCL-H材料不仅初始时断裂伸长率高,而且在降解过程中能始终保持较高的弹性。特性黏数测试和表面形态观测结果显示PLCL-J材料的降解速率过快,不适合在支架上应用,而左旋聚乳酸和PLCL-H基本是匀速的水解,且PLCL-H相对于左旋聚乳酸降解速率有一定程度的增加。提示左旋聚乳酸与聚己内酯共混改性比例为95∶5时不仅能保证材料具备支架所需的力学强度,还能显著提高材料的断裂伸长,达到了增塑目的的同时,也加快降解速率,有望成为制备可降解支架的新型材料。     

不同表面电荷微球改性聚乳酸表面的制备及其细胞相容性研究

采用不同的表面活性剂制备得到不同表面电荷性质的聚乳酸微球。并利用表面截留原理,将不同表面电荷性质的微球结合到聚乳酸基材表面,制备获得了不同表面电荷性质的微球改性聚乳酸表面。激光共聚焦显微镜、扫描电镜对改性表面的稳定性、表面形貌的测试结果显示,该方法成功地获得了稳定的、具有不同表面电荷性质的微球改性聚乳酸表面;软骨细胞相容性测试结果表明正电荷表面性质的微球改性聚乳酸表面较其他表面电荷性质的微球改性聚乳酸表面具有更好的细胞相容性,更能促进细胞的黏附、增殖等生长过程。     

电纺丝方法制备卵磷脂改性聚乳酸血管组织工程支架材料

目的为了改善聚乳酸材料的生物相容性和韧性,在PLLA中混合卵磷脂材料进行电纺丝,以制备血管组织工程支架材料。方法使用共混方法制备聚乳酸／卵磷脂材料,利用红外拉曼光谱仪观察其共混性能,使用电纺丝的方法制各血管组织工程支架,并采用滴液法测定接触角和液体渗透法测定孔隙率,最后使用万能试验机考察卵磷脂浓度对共混材料拉伸性能的影响。结果加入卵磷脂对电纺丝纤维的表面形貌没有明显的影响。两种材料经过物理混合后,材料保持了卵磷脂的生物活性。随着卵磷脂含量的增加,共混材料的接触角逐渐降低,由纯PLLA无纺布的75．2°。降至10％浓度卵磷脂的32．5°,证明材料的亲水性逐渐增加。而电纺丝支架的孔隙率为74．4％到81．8％,适合应用于生物医学、组织工程等领域。最后,随着共混材料中卵磷脂浓度的增加,拉伸强度逐渐降低,而断裂伸长率有所增加。结论卵磷脂可以增加聚乳酸材料的亲水性和整体力学强度,使之更加适用于血管组织工程领域。     

碳纤维-聚乳酸-聚乙二醇复合支架的制备及性能检测

背景：长期实验发现聚乳酸-聚乙二醇支架的力学性能及细胞相容性能较差,因此多数研究向支架中加入其他材料,以提高其生物活性及力学性能。 目的：制备改性碳纤维-聚乳酸-聚乙二醇支架,并检测其性能。 方法：采用溶液潘注/粒子沥滤法制备改性碳纤维-聚乳酸-聚乙二醇复合支架。对比改性碳纤维-聚乳酸-聚乙二醇复合支架与聚乳酸-聚乙二醇支架的超微结构、孔隙率、吸水性、降解率及力学性能。将改性碳纤维-聚乳酸-聚乙二醇复合支架与聚乳酸-聚乙二醇支架分别与SD大鼠成骨细胞共培养,12 h后采用沉淀法检测细胞黏附率;培养1,3,5,7,9 d后,采用 MTT 法检测细胞增殖。 结果与结论：聚乳酸-聚乙二醇支架材料表面孔结构分布均匀,孔径为(404.0±10.5) µm;改性碳纤维-聚乳酸-聚乙二醇支架碳纤维表面见大量纵向沟槽,表面孔结构分布均匀,孔径为(433.0±3.0) µm,两组支架孔径比较差异有显著性意义(P < 0.05)。改性碳纤维-聚乳酸-聚乙二醇支架的孔隙率、吸水性、弹性模量和抗压强度、降解率、细胞黏附率与增殖率均高于聚乳酸-聚乙二醇支架(P < 0.05)。表明改性碳纤维的加入改善了聚乳酸-聚乙二醇复合支架的力学性能及细胞相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

多糖改性聚乳酸生物材料的研究进展

本文主要综述了葡聚糖、壳聚糖、淀粉、环糊精、玻璃酸、纤维素等多糖与聚乳酸进行接枝共聚合反应或共混的研究进展。聚乳酸材料中引入糖基成分,有效改善了材料的亲水性,降低材料接触角,减小材料与人体组织、细胞以及生物大分子之间的界面能,增强材料的组织相容性,为医疗装置、缓释药物和组织工程提供了具有多糖功能的亲水性生物医用材料。     

透明质酸的改性及其应用

透明质酸（HA）是广泛分布在软结缔组织细胞外基质（ECM）中的主要蛋白多糖,具有良好的生物相客性和生物降解性,能调节渗透压、流动阻力以及血浆与基质蛋白扩散的选择性,可应用于组织工程和医药领域。HA极易溶于水、降解速度快等良好性能限制了其在某些组织工程和医药领域的应用,因此需要进行化学改性,提高其机械强度,减缓其在组织内的降解速度,进一步扩大其应用前景。HA具有羟基、羧基和乙酰胺基等官能团,可通过交联、酯化、接枝、分子修饰和复合等方法进行改性。     

注射用聚乳酸和交联透明质酸钠凝胶的制备及性能研究

本研究对交联透明质酸钠凝胶的交联工艺以及和自制的聚乳酸微球的不同配比进行研究,成功制备了注射用美容凝胶。对不同交联度和不同配比的溶胀度、流变学、渗透压、动力粘度、稳定性等性能指标进行研究,并对本产品的灭菌稳定性进行了考察。结果表明本产品灭菌后较稳定,均匀细腻,其弹性模量、动力粘度和溶胀度均较好,具有很好的临床应用前景。     

新型改性聚乳酸与成骨细胞相容性的研究

探讨了成骨细胞与新型生物可降解材料乙二胺改性聚乳酸(EMPLA)的细胞相容性。在PLA、EMPLA及玻璃(对照组)上培养成骨细胞,采用细胞形态学观察法和细胞增殖法,在相差显微镜下观察细胞在上生长情况;分别于1、2、4、6d用MTT法记数,绘制生长曲线图。实验结果表明EMPLA组的成骨细胞比PLA组和对照组的形态好,增殖快,说明EMPLA比PLA表现出更好的细胞相容性,EMPLA在生物医学,特别是在组织工程领域存在着广泛的应用性。     

经骨形态发生蛋白7成骨预处理聚乳酸三维支架的体外培养

BACKGROUND: To improve the cell affinity of polylactic acid, the three-dimensional polylactic acid scaffold is made after pretreatment with bone morphogenetic protein 7 (BMP7). OBJECTIVE: To evaluate the compatibility of BMP7-pretreated three-dimensional polylactic acid scaffold with  periosteum-derived cells.  METHODS: Passage 3 human periosteum-derived cells undergoing osteogenic induction at a density of 1×109/L were seeded into culture media containing the three-dimensional polylactic acid scaffold (experimental group) or seeded into simple culture media (control group). In the experimental group, the scaffold was pretreated with BMP7 for 24 hours. At 1, 3, 5, 7, 9, 11 days after culture, cell counting kit-8 method was used to measure cellular proliferation; at 3, 6, 9, 12 days, the cell-scaffold complex was observed under an electron microscope. RESULTS AND CONCLUSION: In the two groups, the cells had an S-shaped growth curve. Compared with the control group, the cell proliferation in the experimental group was faster at the logarithmic phase, but slower at the stationary phase (P < 0.05). Under the transmission electron microscope, in the experimental group, the number of adherent cells was increased gradually, and the cells grew well with exuberant organelles at 3-6 days of co-culture, but cell aging and apoptosis were found at 9 days of co-culture. Under the scanning electron microscope, in the experimental group, the number of adherent cells on the scaffold surface gradually increased at 3-9 days of co-culture, and then cell apoptosis was notable at 12 days. These findings indicate that BMP7-pretreated three-dimensional polylactic acid scaffold has good cytocompatibility, and the optimal in vitro co-culture duration is 1 week.     

胶原改良聚乳酸电纺丝支架用于组织工程化输尿管的体外构建***

背景：聚乳酸是一种应用广泛的细胞支架材料,但其疏水性和缺乏细胞识别信号影响了在组织工程器官构建中的应用。 目的：探讨Ⅰ型胶原蛋白改良聚乳酸电纺丝支架体外构建组织工程化输尿管的可行性。 方法：用Ⅰ型胶原蛋白醋酸溶液冻干法处理聚乳酸电纺丝,使Ⅰ型胶原蛋白吸附于电纺丝纤维表面,制成胶原改良电纺丝支架。将分离培养的输尿管上皮细胞分别接种于改良聚乳酸电纺丝支架和未处理的聚乳酸电纺丝支架上。 结果与结论：MTT检测显示输尿管上皮细胞在改良支架中生长良好,细胞整体活性在各时间点均明显优于未处理的聚乳酸电纺丝支架上的细胞。扫描电镜观察发现细胞在改良支架表面黏附良好,接种后5 d,支架表面大部分已被增殖的输尿管上皮细胞覆盖。说明胶原改良聚乳酸电纺丝支架能明显提高种子细胞的黏附和增殖活性,可用于体外构建组织工程化输尿管。 关键词：输尿管;电纺丝;聚乳酸;胶原;黏附;增殖;组织工程 doi:10.3969/j.issn.1673-8225.2012.12.002     

The clinical application of autologous bioengineered skin based on a hyaluronic acid scaffold.

The aim of this work was to generate an in vitro skin substitute harbouring autologous fibroblasts, keratinocytes and melanocytes, to establish a new one-step clinical method in problems associated with skin disorders. Here we present a case of a nine-year-old girl with a congenital giant nevus treated by surgical approach, with primary co-cultures of keratinocytes, melanocytes and fibroblasts obtained from autologous skin biopsy. Generally these lesions need to be removed to avoid the risk of transformation into malignant melanoma. With this purpose we analyzed the melanocytes contained in the new skin substitute for the presence of genetic alterations correlated to increased risk for melanoma. The organotypical cultures were designed including an engineered scaffold of a non-woven mesh of hyaluronic acid (HYAFF11). This biomaterial has been previously demonstrated to be the most suitable to maintain polarity and to support the in vitro constructs. Six dermal-epidermal skin substitutes were transplanted and 14 days after surgery the re-epithelialized area was about 90%. Our results suggest that this new dermal-epidermal construct not only reduces hospitalization time and ameliorates scar retraction, but might also represent a solution for the high risk of developing a tumour derived from the original nevus.     

静电纺丝构建胶原-透明质酸钠-硫酸软骨素组织工程关节软骨支架的工艺探索

目的探索以胶原、透明质酸钠和硫酸软骨素三种细胞外基质为原料,利用静电纺丝技术构建组织工程关节软骨支架的工艺。方法固定静电纺丝的参数,通过改变溶剂的种类,浓度和三种原料之间的比例,探索胶原-透明质酸钠-硫酸软骨素复合支架的纺丝条件。结果胶原-透明质酸钠-硫酸软骨素复合支架纺丝的最佳溶剂是3-氟乙醇和水的混合溶剂(v:v,1:1),最佳纺丝浓度范围为80~120mg/m L,三种原料支架的最佳比例范围为6~8:1:1~2。支架纤维的直径和孔隙率则由原料的浓度和比例共同决定;支架降解性能良好,降解速度主要由胶原含量决定。结论研究者成功的利用静电纺丝技术构建了胶原-透明质酸钠-硫酸软骨素复合组织工程软骨支架。这种支架在成分和形态上都可以较好的模拟关节软骨细胞外环境,是一种具有良好应用前景的组织工程关节软骨支架。     

Characteristics of high-molecular-weight hyaluronic acid as a brain-derived neurotrophic factor scaffold in periodontal tissue regeneration

Brain-derived neurotrophic factor (BDNF), for which bovine collagen-derived atelocollagen is used as a scaffold, enhances periodontal tissue regeneration. However, a scaffold that does not contain unknown ingredients is preferable. Since the synthesized high-molecular-weight (HMW)-hyaluronic acid (HA) is safe and inexpensive, we evaluated the efficacy of HMW-HA as a BDNF scaffold. CD44, a major receptor of HA, was expressed in cultures of human periodontal ligament cells, and HMW-HA promoted the adhesion and proliferation of human periodontal ligament cells, although it did not influence the mRNA expression of bone (cementum)-related proteins. The in vitro release kinetics of BDNF from HMW-HA showed that BDNF release was sustained for 14 days. Subsequently, we examined the effect of BDNF/HMW-HA complex on periodontal tissue regeneration in dogs. A greater volume of newly formed alveolar bone and a longer newly formed cementum were observed in the BDNF/HMW-HA group than in the HMW-HA group, suggesting that HMW-HA assists the regenerative capacity of BDNF, although HMW-HA itself does not enhance periodontal tissue regeneration. Neither the poly (lactic-co-glycolic acid) group nor the BDNF/poly (lactic-co-glycolic acid) group enhanced periodontal tissue regeneration. In conclusion, HMW-HA is an adequate scaffold for the clinical application of BDNF.     

Feasibility of chitosan-based hyaluronic acid hybrid biomaterial for a novel scaffold in cartilage tissue engineering

In this study, we hypothesized that hyaluronic acid could provide superior biological effects on the chondrocytes in a three-dimensional culture system. To test this hypothesis, we investigated the in vitro behavior of rabbit chondrocytes on a novel chitosan-based hyaluronic acid hybrid polymer fiber. The goal of the current study was to show the superiority of this novel fiber as a scaffold biomaterial for cartilage tissue engineering. Chitosan polymer fibers (chitosan group) and chitosan-based hyaluronic acid hybrid polymer fibers (HA 0.04% and HA 0.07% groups, chitosan coated with hyaluronic acid 0.04% and 0.07%, respectively) were originally developed by the wetspinning method. Articular chondrocytes were isolated from Japanese white rabbits and cultured in the sheets consisting of each polymer fiber. The effects of each polymer fiber on cell adhesivity, proliferation, morphological changes, and synthesis of the extracellular matrix were analyzed by quantitative a cell attachment test, DNA quantification, light and scanning electron microscopy, semi-quantitative RT-PCR, and immunohistochemical analysis. Cell adhesivity, proliferation and the synthesis of aggrecan were significantly higher in the hybrid fiber (HA 0.04% and 0.07%) groups than in the chitosan group. On the cultured hybrid polymer materials, scanning electron microscopic observation showed that chondrocytes proliferated while maintaining their morphological phenotype and with a rich extracellular matrix synthesis around the cells. Immunohistochemical staining with an anti-type II collagen antibody demonstrated rich production of the type II collagen in the pericellular matrix from the chondrocytes. The chitosan-based hyaluronic acid hybrid polymer fibers show great potential as a desirable biomaterial for cartilaginous tissue scaffolds.     

神经干细胞与透明质酸水凝胶材料生物相容性的研究

目的:评价神经干细胞与改性透明质酸水凝胶支架新材料的生物相容性,研究该透明质酸水凝胶支架作为中枢神经组织工程载体材料的可行性,为用组织工程及干细胞技术治疗中枢神经系统损伤提供基础。方法:以冷冻干燥法制备透明质酸水凝胶材料支架,通过化学接枝法将抗Nogo受体抗体(Anti-NogoR)和多聚赖氨酸(poly-l-lysine,PLL)分子接枝到水凝胶上对其改性,制成新的支架材料。体外培养胚胎13.5d大鼠前脑泡神经干细胞.将神经干细胞与生物支架共培养,通过扫描电镜观察透明质酸水凝胶的内部结构及神经干细胞在支架材料上的粘附与生长情况,通过细胞免疫组织化学技术观察神经干细胞在透明质酸水凝胶材料上的存活与分化情况。结果:制备的透明质酸水凝胶材料具有疏松的三维多孔结构,神经干细胞在支架材料上能够粘附并且有突起长出,生长良好。神经干细胞在支架材料上能够分化。结论:神经干细胞与经过改性的透明质酸水凝胶新材料有很好的生物相容性,能够在材料上存活分化。该新透明质酸水凝胶材料有望作为修复中枢神经损伤的组织工程载体。     

胶原/透明质酸膜与明胶海绵支架材料力学及组织相容性的比较

背景：课题组前期实验证明胶原/透明质酸膜具有良好的力学性能和组织相容性。 目的：观察复合材料胶原/透明质酸膜及明胶海绵的生物学性能。 方法：应用材料复合交联的实验方法构建胶原/透明质酸膜并测定胶原/透明质酸膜、明胶海绵支架的力学性能。将支架材料种植于兔皮下,按照2,4,6,8,12周不同时间点评价材料在体内的降解情况和组织相容性。 结果与结论：①成功制备了胶原/透明质酸膜。②胶原/透明质酸膜具有较好的韧性和抗张强度,明胶海绵的力学性能不够理想。③两种材料在体内的降解均符合生物材料的组织反应过程,胶原/透明质酸膜在体内12周可完全降解,明胶海绵约6周完全降解。④胶原/透明质酸膜与平滑肌细胞的黏附率高,细胞的增殖和代谢状况较好,而明胶海绵的细胞黏黏附和增殖率相对较低。说明胶原/透明质酸膜具有较好的生物学性能。     

Preparation and characterization of a chitosan/galactosylated hyaluronic acid/heparin scaffold for hepatic tissue engineering

Cell culture microenvironment and hepatocyte-specific three-dimensional tissue-engineering scaffold play important roles for bioartificial liver devices. In the present study, highly porous sponge scaffolds composed of chitosan (CS) and galactosylated hyaluronic acid (GHA, galactose moieties were covalently coupled with hyaluronic acid through ethylenediamine), were prepared by freezing-drying technique. Because the growth factors specifically bind to heparin with a high affinity and biological stability of the growth factors are modulated by heparin. Heparin was added into CS/GHA scaffold under mild conditions. The effects of heparin on the morphology, structure, porosity, mechanical properties of the CS/GHA/heparin scaffold were studied. CS/GHA scaffold containing heparin maintains the porous structure and good mechanical properties. Furthermore, addition of heparin with the growth factors into the scaffold resulted in a significantly improved the microenvironment of cell growth and prolonged liver functions of the hepatocytes such as albumin secretion, urea synthesis and ammonia elimination. These results indicate that this CS/GHA/heparin scaffold is a potential candidate for liver tissue engineering.