交联温度对京尼平交联胶原／壳聚糖组织工程支架的影响

[目的]通过研究材料的孔径、交联度、溶胀率、降解率、细胞毒性及组织相容性的变化,探讨交联温度对京尼平交联胶原/壳聚糖支架的影响.[方法]采用冷冻干燥法制备胶原/壳聚糖复合多孔支架,分别于4℃、20℃、36℃条件下,在0.5%京尼平水溶液中交联24 h.以未交联的胶原/壳聚糖复合多孔支架作为对照,评价所得支架的孔径、交联度、溶胀率、降解率、细胞毒性及组织相容性特点.[结果]随交联温度升高,支架的交联度明显增大,溶胀率和降解率逐渐减小.4℃组支架交联度47.88%土6.4%,溶胀率为721%±46%,4周后降解3.95%±6.4%;20℃组支架交联度67.69%±3.6%,溶胀率为662%±72%,4周降解0.91%±5.9%;36℃组支架交联度70.32%±5.7%,溶胀率为635%±27%,4周降解0.66%±7.3%,三组上述观察指标均优于未交联组(P/0.01).[结论]京尼平交联可以显著降低胶原/壳聚糖支架的降解率和溶胀率,且对支架结构和生物相容性无明显影响.交联温度增加可以提高支架的交联度和抗降解能力,较快获得具有良好生物相容性和降解率的组织工程支架.     

壳聚糖与型胶原复合制作组织工程软骨支架及其性能研究

目的　探讨采用壳聚糖与 型胶原复合制作新型组织工程软骨三维多孔支架的方法,并对其理化性能进行检测。　方法　将精制88%脱乙酰度壳聚糖溶于0 .2 mol/ L 醋酸溶液制成2 %溶液,高纯度猪 型胶原溶于0 .5 m ol/ L醋酸溶液制成1%溶液,两者按4∶1(重量比)充分搅拌混合,采用冷冻干燥法制成壳聚糖与 型胶原复合支架。采用碳化二亚胺/ N-羟基琥珀酰亚胺对支架进行交联,力学测定比较支架交联前后的强度变化,扫描电镜观察其超微结构,于2、4、6和8周经溶菌酶体外降解实验测定其体外降解性。　结果　制备的复合支架成形良好,交联后其力学强度明显增加。扫描电镜显示壳聚糖与 型胶原成分在支架内分布均匀,支架内孔洞相互连通似海绵状,孔径10 0～2 5 0 μm。各时间段复合支架体外降解较单纯壳聚糖支架快。　结论　壳聚糖与 型胶原复合成功地制作成了三维多孔复合支架。其理化性能及体外降解测定,可以作为支架载体,应用于组织工程软骨的构建。     

壳聚糖与Ⅱ型胶原复合制作组织工程软骨支架及其性能研究

目的探讨采用壳聚糖与Ⅱ型胶原复合制作新型组织工程软骨三维多孔支架的方法,并对其理化性能进行检测. 方法将精制88%脱乙酰度壳聚糖溶于0.2 mol/L醋酸溶液制成2%溶液,高纯度猪Ⅱ型胶原溶于0.5 mol/L醋酸溶液制成1%溶液,两者按4∶1(重量比)充分搅拌混合,采用冷冻干燥法制成壳聚糖与Ⅱ型胶原复合支架.采用碳化二亚胺/ N-羟基琥珀酰亚胺对支架进行交联,力学测定比较支架交联前后的强度变化,扫描电镜观察其超微结构,于2、4、6和8周经溶菌酶体外降解实验测定其体外降解性. 结果制备的复合支架成形良好,交联后其力学强度明显增加.扫描电镜显示壳聚糖与Ⅱ型胶原成分在支架内分布均匀,支架内孔洞相互连通似海绵状,孔径100～250 μm.各时间段复合支架体外降解较单纯壳聚糖支架快. 结论壳聚糖与Ⅱ型胶原复合成功地制作成了三维多孔复合支架.其理化性能及体外降解测定,可以作为支架载体,应用于组织工程软骨的构建.     

纳米纱/多孔纳米纤维支架的生物相容性

目的通过体内外实验评价纳米纱/多孔纳米纤维材料的生物相容性,为构建仿生组织工程纤维环及进一步开展体内实验奠定基础。方法通过静电纺丝技术制备取向纳米纤维支架(AFS)、取向纳米纱支架(AYS)、三维多孔纳米纤维支架(3DPS)。将大鼠骨髓间充质干细胞(BMSC)接种于3种支架,静态培养,观察细胞在支架上黏附、生长和增殖情况,评价支架的体外生物相容性。将3种支架植入大鼠皮下,在不同时间点取材,通过HE染色、异物巨细胞的形态数目及炎性因子基因表达量评价支架的体内生物相容性。结果体外实验表明BMSC在3种支架上均能黏附、增殖,生长良好。体内实验表明大鼠皮下植入3种支架后早期(1～2周)均有轻度炎性反应,4周后炎性细胞浸润减少,异物巨细胞数量逐渐减少。炎性因子基因表达水平与炎性细胞浸润程度相符。结论 AYS和3DPS具有良好的生物相容性,可用于进一步体内实验研究。     

三种胶原-壳聚糖多孔支架组织相容性的初步研究

目的制备3种具有良好稳定性的胶原-壳聚糖多孔支架,初步探讨其植入体内后的组织相容性。方法冻干法制备胶原-壳聚糖多孔支架,分别采用真空干热和戊二醛对其交联,制备未交联(材料1)、真空干热交联(材料2)和戊二醛交联(材料3)3种胶原-壳聚糖多孔支架,扫描电镜观察支架微观结构。将12只家兔随机分为4组(n=3),3种支架材料分别交叉埋植入12只家兔耳背部皮下,术后观察、记录全身情况及手术区变化,分别于术后3、7、14及28 d组织切片下见3种材料的稳定性和组织相容性。结果扫描电镜下见3种支架均具有三维多孔结构,孔径分别为120±10、80±15和170±20μm,孔隙率均大于90%。大体观察:实验家兔术后全身情况良好,手术区红肿轻微,切口均愈合良好。组织学观察:材料1降解吸收迅速,能引起明显的炎性反应,材料2降解较快,炎性反应不及材料1明显,材料3降解较慢,炎性反应轻微,术后组织再生较快。结论胶原-壳聚糖多孔支架具有适合组织再生的三维多孔结构,交联能提高胶原-壳聚糖多孔支架的早期稳定性和组织相容性,戊二醛交联优于真空干热交联。     

重组人骨形态发生蛋白-2壳聚糖纳米微球的制备及检测

目的 制备负载重组人骨形态发生蛋白-2(rhBMP-2)壳聚糖纳米微球,并检测其粒径、形态、降解及药理特性,以评估壳聚糖纳米微球作为rhBMP-2缓释载体的可行性.方法 以壳聚糖为原料、三聚磷酸钠为交联剂,通过离子交联法制备负载rhBMP-2壳聚糖纳米微球,应用透视电镜观察微球的形态、激光粒径,分析其粒径分布、溶菌酶降解,了解降解特性.通过酶联免疫吸附实验(ELISA)检测rhBMP-2壳聚糖微球的载药率、包封率和释药规律.结果 离子交联法制备的壳聚糖纳米微球,平均粒径大小为230nm,成球性较好,包封率和载药率分别为(66.867±4.575)％、(33.437±2.290)μg/mg;体外释药试验rhBMP-2可以从壳聚糖纳米微球中缓慢释放,释放行为符合双向动力学规律,整个释放过程可达30 d.结论 离子交联法可成功制备壳聚糖纳米微球并具有缓释rhBMP-2的能力,为进一步应用于骨组织工程研究提供实验依据.     

交联温度对京尼平交联壳聚糖/藻酸盐组织工程支架的影响

[目的]通过对壳聚糖/藻酸盐复合支架材料表面结构、降解率、细胞毒性、孔隙率、含水量以及生物力学性能变化的研究,探究交联温度对京尼平交联壳聚糖/藻酸盐组织工程支架的影响.[方法]运用冷冻干燥法制备壳聚糖/藻酸盐支架材料,分别在4℃、25℃、37℃条件,于0.5％京尼平溶液中交联24 h,作为实验组.以未用京尼平交联的支架材料作为对照组,评价支架材料降解率、细胞毒性、孔隙率、含水量以及生物力学性能的特点.[结果](1)伴随交联温度升高,支架材料的颜色从浅紫色变为紫黑色,未交联的支架材料为白色;(2)降解率4周后在4℃为21.54％±3.07％、25℃组为9.9％±1.2％、37℃组为8.98％±0.79％.其中,37℃和25℃组抗降解能力优于4℃组(P＜0.05).各实验组均优于对照组(P＜0.01);(3)弹性模量在4℃组为0.84±0.55,25℃组为1.44±0.06,37℃组为1.53±0.02,对照组为0.79±0.16.对照组与25℃组及37℃组之间差异有统计学 意义(P＜0.05);(4)孔隙率、含水量、细胞毒性各实验组间未见明显差异.[结论]随着交联温度的提高,支架材料的抗降解能力、抗拉伸性能增加,且对支架材料的结构、细胞毒性、孔隙率以及含水量无明显影响.     

静电纺丝壳聚糖-明胶复合纤维的制备和体外生物相容性评价

目的采用静电纺丝技术制备壳聚糖-明胶复合纤维,体外评价其生物相容性。方法采用扫描电镜(SEM)观察纤维支架的表面形貌,考察纺丝溶液浓度、黏度以及壳聚糖/明胶质量比对纤维直径和结构的影响。将人成纤维细胞接种在纤维支架表面,绘制细胞生长曲线,观察细胞在支架表面的形态。结果通过静电纺丝技术,制备的壳聚糖-明胶复合纤维均匀、光滑,无珠状结构,纤维平均直径为600 nm～1.6μm。随着纺丝溶液浓度和黏度增加,纤维平均直径增大;随着壳聚糖/明胶质量比增加,纤维直径也随之增大。成纤维细胞在复合纤维支架上生长良好,增殖快,并且保持较好的成纤维细胞形态。结论通过静电纺丝技术制备的壳聚糖-明胶复合纤维具有良好的生物相容性,有望作为皮肤组织工程的支架材料。     

大鼠骨髓间充质干细胞复合n-HA/PLA支架异位成骨的实验研究

[目的]研究大鼠骨髓间充质干细胞(BMSCs)复合纳米羟基磷灰石/聚乳酸(n-HA/PLA)支架材料体内异位成骨情况.[方法]取SD大鼠股骨胫骨骨髓,进行贴壁培养BMSCs,将第3代BMSCs接种到n-HA/PLA支架材料上,加入成骨诱导液,3d后置人大鼠体内,设为实验组;将单纯支架材料置入组为对照组.4、8、12周时取材进行大体和组织学观察.[结果]8、12周时实验组可见类骨质成分形成,并且支架材料维持置入时形状,对照组无类骨质形成.[结论]BMSCs复合n-HA/PLA构建组织工程骨有很好的异位成骨能力,且能在体内维持良好塑型.     

壳聚糖/亚磷酸化壳聚糖复合海绵复合人脐带间充质干细胞用于异位成骨的实验研究

目的通过构建壳聚糖/亚磷酸化壳聚糖复合海绵,与人脐带间充质干细胞(human umbilical cordmesenchymal stem cells,hUCMSCs)复合构建组织工程骨并行成骨诱导培养,探讨其异位成骨效果,为骨组织工程寻找理想支架材料。方法在壳聚糖分子中引入亚磷酸根基团,制备亚磷酸化壳聚糖,并进行表征。分别将浓度为2%的壳聚糖和亚磷酸化壳聚糖溶液,按1∶1体积比混合均匀,构建壳聚糖/亚磷酸化壳聚糖复合海绵;然后在模拟体液中进行原位矿化,通过扫描电镜观察矿化前后复合海绵的结构。用酶消化法分离培养hUCMSCs,取生长良好的第3代细胞与壳聚糖/亚磷酸化壳聚糖复合海绵复合培养,构建细胞-支架复合物,并行成骨诱导培养。成骨诱导培养1、2周,分别于光镜及扫描电镜下观察细胞黏附情况;培养1、2、3、4、5、6 d时,MTT法分析细胞增殖情况。取3～4月龄新西兰大白兔40只,雌雄不限,体重2.1～3.2 kg,平均2.5 kg;制备双侧竖脊肌肌袋,在每只兔右侧肌袋内植入细胞-支架复合物(A组,n=40),于其中20只兔左侧肌袋植入壳聚糖/亚磷酸化壳聚糖复合海绵(B组,n=20),剩余20只兔左侧肌袋不植入材料(C组,n=20)。术后观察动物一般情况,4周后处死动物取材,行大体及组织学观察。结果亚磷酸化壳聚糖分析表明亚磷酸化反应主要发生在羟基上,其质子类型和化学位移强度与化学结构一致。扫描电镜观察到壳聚糖/亚磷酸化壳聚糖复合海绵孔洞均匀,孔壁较薄;原位矿化后孔壁表面有钙磷涂层,晶体颗粒生成;细胞在壳聚糖/亚磷酸化壳聚糖复合海绵支架上黏附、生长良好。体内实验大体观察A组可见细胞-支架复合物大小、形态基本保持原状,质地有所增韧,材料周围有薄层结缔样组织;B组复合海绵体积缩小,质地松软;C组肌袋手术创口已愈合。组织学观察A组支架材料部分吸收,边缘有均质类骨物质出现,并见成骨细胞;B组植入区形成圆形空腔,残留壳聚糖支架网络;C组创面基本愈合,肌肉纤维间可见少量淋巴细胞浸润。结论壳聚糖/亚磷酸化壳聚糖复合海绵是一种具有良好生物相容性的支架材料,与hUCMSCs复合构建的组织工程骨在兔体内可异位成骨。     

Modulation of annulus fibrosus cell alignment and function on oriented nanofibrous polyurethane scaffolds under tension

Background contextAnnulus fibrosus (AF), a component of the intervertebral disc (IVD), is always under tension in vivo, a condition that must be taken into consideration when tissue engineering an IVD. Loss of the tensile forces has been implicated in the pathogenesis of disc degeneration characterized by mechanical and structural breakdown of the AF.PurposeIn this study, we hypothesize that tensile forces modulate cellular and molecular behavior of AF cells grown on nanofibrous scaffolds in vitro.Study design/settingBovine AF cells were seeded onto strained electrospun-aligned nanofibrous polycarbonate urethane (PU) scaffolds. Tension was either maintained throughout the culture duration (monotonic) or removed after 24 hours (relaxed).MethodsThe effect of tension on AF cells cultured on PU scaffolds was evaluated over 7 days by scanning electron microscopy, biochemical assays, immunofluorescence microscopy, and quantitative polymerase chain reaction.ResultsCells grown on the relaxed scaffold were significantly more proliferative, synthesized more collagen and had increased collagen type I and TGFβ-1 gene expression; however these cells were not as aligned as were the cells and matrix on monotonic strained scaffolds. The alignment of AF cells grown on monotonic scaffolds correlated with significantly greater scaffold elastic modulus on day 7. Additionally, the cellular response to the change in strain was delayed by 3 to 5 days after tension release, which correlated with the time at which changes in scaffold length were detected.ConclusionsThis study demonstrated that AF cells respond at the molecular and cellular level to the changes in matrix/scaffold tension. This suggests that it may be necessary to determine the optimal elastic modulus and applied tensile forces to tissue engineer an AF that mimics the native tissue. Furthermore, this study provides insight into how changes in tensile forces may lead to changes in the AF cell function.     

Bone Morphogenetic Protein-6-loaded Chitosan Scaffolds Enhance the Osteoblastic Characteristics of MC3T3-E1 Cells

The purpose of this study is to investigate the convenience of bone morphogenetic protein-6 (BMP-6)-loaded chitosan scaffolds with preosteoblastic cells for bone tissue engineering. MC3T3-E1 cells were seeded into three different groups: chitosan scaffolds, BMP-6-loaded chitosan scaffolds, and chitosan scaffolds with free BMP-6 in culture medium. Tissue-engineered constructs were characterized by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide assay, scanning electron microscopy (SEM), mineralization assay (von Kossa), alkaline phosphatase (ALP) activity, and osteocalcin (OCN) assays. BMP-6-loaded chitosan scaffolds supported proliferation of the MC3T3-E1 mouse osteogenic cells in a similar pattern as the unloaded chitosan scaffolds group and as the chitosan scaffolds with free BMP-6 group. SEM images of the cell-seeded scaffolds revealed significant acceleration of extracellular matrix synthesis in BMP-6-loaded chitosan scaffolds. Both levels of ALP and OCN were higher in BMP-6-loaded chitosan scaffold group compared with the other two groups. In addition, BMP-6-loaded scaffolds showed strong staining in mineralization assays. These findings suggest that BMP-6-loaded chitosan scaffold supports cellular functions of the osteoblastic cells; therefore, this scaffold is considered as a new promising vehicle for bone tissue engineering applications.     

Preparation and evaluation of polycaprolactone/chitosan/Jaft biocompatible nanofibers as a burn wound dressing

Tissue engineering is an emerging method for replacing damaged tissues. In this study, the potential application of electrospun polycaprolactone/chitosan/ the internal layer of oak fruit (Jaft) as skin scaffolds was investigated. A combination of Polycaprolactone (PCL), chitosan (CH), and the internal layer of oak fruit (Jaft) was used to incorporate mechanical properties of synthetic polymers, biological properties of natural polymers, and antibacterial activity of Jaft. Physical and morphological characteristics of prepared scaffolds were investigated using a scanning electron microscope (SEM), mechanical analysis, swelling ratio, and contact angle. Moreover, chemical and biological properties were evaluated by Fourier-transform infrared spectroscopy (FTIR), chromatography, flow cytometry, DAPI staining, MTT assay, and trypan blue exclusion assay. Obtained results demonstrated that the fabricated scaffolds have good mechanical properties. Moreover, the addition of chitosan and Jaft to the PCL scaffolds improved their water absorption capacity as well as surface hydrophilicity. MTT results showed the fabricated nanofibrous scaffolds have adequate cell viability, which is higher than the cell culture plate at each time point of culture. Furthermore, SEM images of cultured scaffolds, trypan blue exclusion assay, and DAPI staining confirmed that fibroblast cells could be well-attached and proliferate on the PCL/CH/Jaft scaffolds. Results have proven that this novel bioactive scaffold has promising mechanical properties, suitable biocompatibility in vitro, and in vivo. Consequently, it could be a promising candidate for skin tissue engineering applications.     

Effects of a chitosan scaffold containing TGF-beta1 encapsulated chitosan microspheres on in vitro chondrocyte culture

The objectives of this study were (1) to develop a three-dimensional chitosan scaffold in combination with transforming growth factor-beta1 (TGF-beta1)-loaded chitosan microspheres and (2) to evaluate the effect of the TGF-beta1 release on the chondrogenic potential of rabbit chondrocytes in the scaffolds. TGF-beta1 was loaded into chitosan microspheres using an emulsion-crosslinking method, resulting in spherical shapes with a size ranging from 0.3 to 1.5 microm. Controlled release of TGF-beta1, as measured by enzyme-linked immunosorbent assay (ELISA), was observed with chitosan microspheres over 7 days. Chitosan solutions (2% and 3%) were fabricated into two types of scaffolds with different pore morphologies and mechanical properties using a freeze-drying technique, with the result that scaffold with higher concentrations showed smaller pores and lower porosity, leading to a much stronger scaffold. The TGF-beta1 microspheres were incorporated into the scaffolds at a concentration of 10 ng TGF-beta1/scaffold and then chondrocytes seeded into each scaffold and incubated in vitro for 2 weeks. The 2% chitosan scaffolds showed higher cell attachment levels than the 3% chitosan scaffolds (P < 0.01), regardless of the TGF-beta1 microspheres. Both the proliferation rate and glycosaminoglycan (GAG) production were significantly higher for scaffolds incorporating TGF-beta1 microspheres than for the control scaffolds without microspheres 10 days after incubation. Extracellular matrix staining by Safranin O and immunohistochemistry for type II collagen both significantly increased in scaffolds containing TGF-beta1 microspheres. These results suggest that the TGF-beta1 microsphere incorporated in scaffolds have the potential to enhance cartilage formation.     

软骨细胞外基质与壳聚糖复合制备组织工程软骨支架及其性能研究

 目的 探讨采用壳聚糖与脱细胞软骨基质复合制备组织工程软骨支架的可行性,检测其理化性能和细胞相容性。方法 取天然人软骨粉碎.取 100 nm~5μm 软骨微丝,脱细胞处理后制备为质量浓度 1%悬液.与质量浓度 2%壳聚糖醋酸溶液按 1颐1(重量比)充分搅拌混合,冷冻干燥制备复合支架。对支架交联,并进行组织学、扫描电镜、孔隙率及吸水性测定、生物力学评估, MTT法分析支架浸提液毒性。分离培养犬软骨细胞.种植到支架上.倒置显微镜、电镜观察细胞在支架的生长、分化情况。结果 组织学显示支架中无细胞碎片残留.II型胶原免疫组化染色阳性。扫描电镜显示支架内孔洞相互连通似海绵状.孔径为(136.2±34.9)μm.孔隙率为 81.4%±3.5%.吸水性约为 1525.7±129.3%。支架纵向弹性模量为(1.940±0.335)MPa。 MTT法显示不同浓度支架浸提液与对照培养液吸光度值比较.差异无统计学意义(P>0.05)。倒置显微镜观察.细胞在支架上粘附良好.扫描电镜下细胞在支架上均匀分布.呈圆形或椭圆形.有基质分泌。结论 软骨细胞外基质和壳聚糖复合制备的仿生三维多孔双相支架.具有较高的孔隙率和吸水性.良好的生物力学特性.无毒.生物相容性良好.是组织工程软骨的良好支架载体。     

Alginate and chitosan polyion complex hybrid fibers for scaffolds in ligament and tendon tissue engineering

Selecting the material for a scaffold is critically important for the success of tissue engineering. To simplify complicated biosynthetic matrices and achieve a novel class of potential materials, a model of polyion complex fibers was prepared from alginate and chitosan. In the current in vitro study, we thought that alginate-based chitosan hybrid biomaterials could provide excellent supports for fibroblast adhesion. In the current study, alginate polymer fiber (alginate group) and alginate-based chitosan hybrid polymer fibers (alginate with 0.05% chitosan, alginate-chitosan 0.05% group; alginate with 0.1% chitosan, alginate-chitosan 0.1% group) were originally prepared. We investigated the adhesion behavior of rabbit tendon fibroblast onto alginate polymer fibers versus the adhesion of the fibroblast onto alginate-based chitosan hybrid polymer fibers. Furthermore, mechanical properties and synthesis of the extracellular matrix were investigated. Mechanically, the novel fiber has considerable tensile strength of more than 200MPa. We demonstrated that the alginate-based chitosan hybrid polymer fibers showed much improved adhesion capacity with fibroblast compared with alginate polymer fiber. Additionally, morphologic studies revealed the dense fiber of the type I collagen produced by the fibroblast in the hybrid polymer fibers. We concluded that an alginate-based chitosan hybrid polymer fiber has considerable potential as a desirable biomaterial scaffold for tendon and ligament tissue engineering.     

促进内皮祖细胞生长的细胞外基质组织工程血管支架的研究

目的 研究鼠骨髓来源内皮祖细胞(endothelial progenitor cells,EPCs)在不同类型细胞外基质支架上的生长特性,为EPCs生长寻找新的生物组织工程血管支架.方法 EPCs种植于细胞外基质支架(extracellular matrix,ECM)上.培养不同时间点用免疫荧光技术鉴定并细胞记数;电镜观察支架表面结构及EPCs的生长情况;Western blotting法、real-time PCR法检测VWF(von Willebrand factor)蛋白及mRNA表达变化.结果 在1、3、5 h 3个检测点的压缩组细胞贴壁率明显高于未压缩组(P<0.01).在1、3、7 d压缩组的细胞数明显高于未压缩组(P<0.05),10d后差异无统计学意义,且压缩组细胞形态较成熟,与内皮细胞相似,有一个较平整的细胞平面.Western blotting检测表明3、7、10 d VWF蛋白在压缩支架上表达比未压缩支架上强,14 d后两组表达相当.real-time PCR结果示3、7、10 d压缩组VWF基因表达量明显高于未压缩组(P<0.01),14 d后两组表达无差异.结论 压缩ECM更能促进EPCs黏附、增殖和分化,可作为一种新的合成人工血管的生物组织工程支架.     

双层细菌纤维素基组织工程尿道支架的设计与初步构建

目的 设计并构筑具有模拟尿道组织微环境的三维微/纳支架材料。方法 通过对尿道脱细胞基质多尺度结构分析,设计仿尿道组织的双层细菌纤维素(Baterial cellulose,BC)基微/纳组织工程尿道支架。采用模板合成法,以明胶多孔支架为模板,在其上静态培养制备兼具微米多孔与纳米纤维的双层BC基微/纳支架材料。结果 双层BC基微/纳支架材料的致密层为细菌纤维素膜,疏松层为相互连通的多孔结构,平均孔径为(167±56)μm,同时在其微米级孔壁表面修饰着模拟天然细胞外基质(Extracellular matrix,ECM)结构的纳米纤维网络,纳米纤维直径为(20~40)nm。结论 采用模板合成法,成功构建出了兼具宏观双层结构、微米级多孔和纳米级纤维的双层BC微/纳组织工程尿道支架。     

Nanobioengineered electrospun composite nanofibers and osteoblasts for bone regeneration

Abstract:  Bone defects represent a medical and socioeconomic challenge. Engineering bioartificial bone tissues may help to solve problems related to donor site morbidity and size limitations. Nanofibrous scaffolds were electrospun into a blend of synthetic biodegradable polycaprolactone (PCL) with hydroxyapatite (HA) and natural polymer gelatin (Gel) at a ratio of 1:1:2 (PCL/HA/Gel) compared to PCL (9%), PCL/HA (1:1), and PCL/Gel (1:2) nanofibers. These fiber diameters were around 411 ± 158 to 856 ± 157 nm, and the pore size and porosity around 5–35 µm and 76–93%, respectively. The interconnecting porous structure of the nanofibrous scaffolds provides large surface area for cell attachment and sufficient space for nutrient transportation. The tensile property of composite nanofibrous scaffold (PCL/HA/Gel) was highly flexible and allows penetrating osteoblasts inside the scaffolds for bone tissue regeneration. Fourier transform infrared analysis showed that the composite nanofiber contains an amino group, a phosphate group, and carboxyl groups for inducing proliferation and mineralization of osteoblasts for in vitro bone formation. The cell proliferation (88%), alkaline phosphatase activity (77%), and mineralization (66%) of osteoblasts were significantly ( P  < 0.001) increased in composite nanofibrous scaffold compared to PCL nanofibrous scaffolds. Field emission scanning electron microscopic images showed that the composite nanofibers supported the proliferation and mineralization of osteoblast cells. These results show that the fabrication of electrospun PCL/HA/Gel composite nanofibrous scaffolds has potential for the proliferation and mineralization of osteoblasts for bone regeneration.     

不同材料人工真皮支架修复猪Ⅲ度烧伤创面比较

目的 比较胶原壳聚糖真皮支架、胶原磺化羧甲基壳聚糖真皮支架及脱细胞基质真皮支架移植于Ⅲ度烧伤创面后,真皮支架的血管化及支架上表皮移植修复创面情况.方法 将3种不同真皮支架各移植于6头猪(共18头猪)Ⅲ度烧伤清创后创面,在植入后1、2、3周对真皮支架血管化、创面、支架上表皮移植愈合和修复情况进行观察,同时用免疫组织化学方法,对CD34阳性信号(新生血管数目)进行检测.以无支架植入的Ⅲ度烧伤清创后创面为对照.结果 胶原磺化羧甲基壳聚糖真皮支架植入后2周支架血管化已基本完成,而胶原壳聚糖和脱细胞基质真皮支架至少需要3周.3种不同材料支架垂直于创面的新生微血管均比无支架对照创面多;不同材料支架组与对照组2周创面比1周创面、3周创面比2周创面CD34的表达均明显增多,胶原磺化羧甲基壳聚糖真皮支架组植入后1、2、3周CD34阳性信号均明显高于相对应的其他3组;胶原磺化羧甲基壳聚糖真皮支架植入后1周,创面植表皮,移植表皮存活良好,而胶原壳聚糖和脱细胞基质真皮支架植入需要2周,其表面移植的表皮细胞才能成活.结论 3种材料的支架均可修复Ⅲ度烧伤创面,而以胶原磺化羧甲基壳聚糖真皮支架的血管化程度最好.