电纺纳米纤维构建组织工程支架研究新进展

电纺是制备纳米纤维的有效方法.纤维直径通常介于数十纳米至数微米之间,与细胞外基质中胶原等纤维支架的尺寸相近.采用天然高分子或合成高分子电纺纤维构建组织工程支架,可以仿生细胞外基质的结构乃至生物学功能,利于细胞的黏附、分化和增殖,引导组织的再生与修复,成为组织工程支架的研究热点.大量研究报道显示,电纺纳米纤维支架可以提供理想的细胞黏附、增殖和分化微环境.简要介绍了静电纺丝技术以及电纺纳米纤维的特点,重点总结了近几年来电纺纳米纤维在构建皮肤、血管、神经、骨与软骨等组织工程支架的研究进展,并展望了纳米纤维支架的应用前景.     

PDGF/BMP-2-CMs/nHA/PLGA复合支架的制备及性能

将壳聚糖缓释微球与可降解多孔支架复合,构建可次第释放不同生长因子的骨组织工程支架,并进行表征和性能研究。首先,制备载骨形态发生蛋白-2的壳聚糖微球(BMP-2-CMs),然后将微球与纳米羟基磷灰石/羟基乙酸(nHA/PLGA)及血小板衍生生长因子(PDGF)按照一定的比例混合,通过粒子沥虑-冷冻干燥复合工艺制备PDGF/BMP-2-CMs/nHA/PLGA复合支架。BMP-2-CMs呈规则球形,粒径分布在4~10μm之间,BMP-2包封率为65.9%,载药量为0.134%。PDGF/BMP-2-CMs/nHA/PLGA复合支架孔径为100~200μm,孔隙率为51.2%,抗压强度为7.7MPa,8周降解率为20.1%。7d时,PDGF和BMP-2累计释放率分别为75.0%和42.2%;14d时,PDGF和BMP-2累计释放率分别为79.9%和53.5%。分析可知,复合支架中释放的PDGF和BMP-2能够持续有效地促进人脐静脉血管内皮细胞(HUVEC)和成骨细胞(MG63)的增殖和分化,具有良好的生物活性。由此可得,PDGF/BMP-2-CMs/nHA/PLGA复合支架能够次第释放PDGF和BMP-2,且能够显著促进HUVEC和MG63的增殖和分化。     

熔融静电纺丝技术在组织工程中的应用

介绍了熔融静电纺丝法的基本原理和特征,对其在组织工程领域上的应用进行了总结,并对其发展前景进行展望。熔融静电纺丝过程无需使用溶剂,生产过程具有环境友好性,电纺纤维无毒,生产效率高,正逐渐受到广泛关注。研究发现,由微/纳米纤维复合而成的组织工程支架可以提供更好的细胞微环境。     

丝素蛋白/膀胱脱细胞基质/透明质酸复合纤维支架的制备及生物学性能研究

以丝素蛋白(RSF)/膀胱脱细胞基质(BAM)/透明质酸(HA)水溶液为纺丝液,通过静电纺丝法制备RSF/BAM/HA复合纤维支架。通过扫描电子显微镜、ELISA、MTT以及荧光显微镜对支架的形貌和体外生物学性能进行表征。结果表明,3组分比例不变时,纺丝液浓度对纤维支架形貌影响不明显;从支架中成功检测出血管内皮生长因子(VEGF)、血小板衍化生长因子(PDGF-BB)和角化细胞生长因子(KGF)及其缓释行为曲线;这些生物活性因子使RSF/BAM/HA复合纤维支架比纯RSF支架更有利于细胞的粘附与增殖。     

静电纺丝制备聚乙烯醇/再生柞蚕丝素蛋白复合纳米纤维

将聚乙烯醇(PVA)与再生柞蚕丝素蛋白(RWSF)共混,通过静电纺丝技术制备了PVA/RWSF复合纳米纤维,在保持材料降解性能和力学强度不变的前提下,获得了具有生物活性的表面。应用正交法优选出PVA/RWSF复合纳米纤维的最佳制备工艺参数。扫描电镜观察到,各组电纺膜中纤维的形貌较好,不同参数条件下纤维的直径和均匀程度有较大差别;方差分析表明,静电纺丝过程中纺丝液浓度、PVA/RWSF质量比和纺丝电压对纤维均匀性的影响显著;结合后期验证性实验确定PVA/RWSF复合纳米纤维最佳电纺参数为电纺液浓度0.09 g/mL、PVA/RWSF质量比90/10、纺丝电压18kV、推进速度1.5mL/h、接收距离14cm,此时制备的纤维均一、纤细,重复性好。     

有序电纺纤维膜的制备方法及在组织工程中的应用进展

静电纺丝是一种简单且有效的制备高分子微纳米纤维的方法。近年来,通过电纺装置的控制制备有序纤维膜已成为研究热点,由此构建的电纺纤维膜支架具有独特的结构和生物学性能,有利于细胞的粘附、增殖和分化,在神经、血管、骨与软骨等组织工程及组织修复中具有良好的应用前景。文中对有序电纺纤维膜的制备方法进行了总结,概述了有序电纺纤维膜在...     

电纺丝聚乳酸纤维支架的制备及其细胞相容性研究

静电纺丝法制备的聚(D,L-乳酸)超细纤维具有孔隙率高、孔径/结构可调、生物相容性良好等特点,已成为组织工程支架材料研究的热点。探讨了纺丝溶液浓度、流量、电压、干燥方式等影响聚(D,L-乳酸)纤维支架形貌的因素,确定了最佳工艺参数为纺丝溶液浓度为0.20g/mL,流速为0.8mL/h,电压为12kV,经真空冷冻干燥,可获得分布比较均匀,直径大多为500～900nm的聚乳酸纤维。体外细胞形貌观察表明聚(D,L-乳酸)纤维支架具有良好的细胞相容性。     

静电纺纳米纤维支架结构的研究进展

静电纺丝作为一种纳米纤维支架的仿生构建方法 ,已在软骨组织工程领域中得到越来越多的应用和关注。但是,由于静电纺纳米纤维支架的孔径过小以及无法精确控制支架的形状影响其向临床应用转化。近年来涌现出许多控制纳米纤维支架结构的方法。本文对控制纳米纤维支架结构的方法进行了综述,并对纳米纤维支架在软骨组织工程中应用的主要挑战和前景,提出了看法。     

基于氧化-还原胺化反应改性海藻酸盐制备载药性电纺纳米复合纤维

以辛胺为疏水改性剂,采用氧化-还原胺化反应制得具有两亲性的海藻酸衍生物(RAOA)。通过FTIR、~1H NMR、荧光光谱和光学接触角测量仪对RAOA的结构和性能进行表征。进而,以聚乙烯醇(PVA)为助纺剂,对疏水改性的RAOA进行电纺性能的研究。通过光学接触角测量仪、电导率仪、流变仪和扫描电子显微镜对RAOA/PVA纺丝液的物理性能和与之相应的RAOA/PVA纳米复合纤维的形貌进行了测试,考察了该电纺纳米复合纤维对疏水性布洛芬的负载和释药性能。结果表明,辛胺成功接枝到海藻酸钠(SA)分子链上,RAOA的临界聚集浓度为0.43 g/L,说明RAOA具有良好的两亲性。氧化-还原胺化反应改性RAOA不能从根本上改变单一RAOA溶液的可纺性,但是它可以改善RAOA/PVA纺丝液的电纺性能,提高RAOA在RAOA/PVA电纺纳米复合纤维中的含量。载药后的SA/PVA电纺纳米复合纤维在释药初期有突释行为,但改性后的RAOA可以有效地减缓布洛芬的释放速度,提高其缓释性能。     

激光熔融静电纺丝法制备PLLA及PLLA/nHA纤维支架及性能研究

利用激光熔融静电纺丝方法制备了PLLA和PLLA/nHA纤维支架,采用FTIR和DSC测试对支架材料的结构和热学性能进行表征,通过熔融电纺对PLLA和PLLA/nHA纤维支架进行体外降解实验,研究了失重率与降解时间的关系。同时对激光熔融和一般溶液电纺得到的PLLA和PLLA/nHA纤维支架进行细胞相容性实验,对两种方法所得支架的安全性进行评价。结果表明:nHA对PLLA的结构和晶型产生影响,并减缓PLLA的降解速度,激光熔融电纺支架更具安全性,其更适合组织工程应用。     

Low-temperature fabrication of macroporous scaffolds through foaming and hydration of tricalcium silicate paste and their bioactivity

A low-temperature fabrication method for highly porous bioactive scaffolds was developed. The two-step method involved the foaming of tricalcium silicate cement paste and hydration to form calcium silicate hydrate and calcium hydroxide. Scaffolds with a combination of interconnected macro- and micro-sized pores were fabricated by making use of the decomposition of a hydrogen peroxide (H₂O₂) solution that acted as a foaming agent and through the hydration of tricalcium silicate cement. It was found possible to control the porosity and pore sizes by adjusting the concentration of the H₂O₂ solution. The in vitro bioactivity of the highly porous scaffolds was investigated by immersion in simulated body fluid (SBF) for 7 days. Hydroxyapatite (HAp) was formed on the surface of the scaffolds. Their bioactivity could be expected to be as good as that of tricalcium silicate cement, making the material competent for the bone tissue engineering application.     

基于介孔硼硅酸盐生物活性玻璃微球的可注射复合骨水泥

以溶胶-凝胶法制备的介孔硼硅酸盐生物活性玻璃微球(MBGS)作为固相, 海藻酸钠(SA)溶液作为液相,开发了一种可注射复合骨水泥。对MBGS中氧化硼/氧化硅的比例对其质构性能及骨水泥的可操作性、抗压强度和生物活性的影响进行表征。实验结果表明, 随着硼含量的增加, MBGS的比表面积从161.71 m²/g增大至214.28 m²/g, 平均孔径以及总孔容也随之增长, 加速了玻璃相中钙离子的释放, 使得玻璃与SA的快速交联, 改善了骨水泥可操作性能和力学性能, 凝固时间由21 min缩短至9 min, 抗压强度由3.4 MPa提升至4.1 MPa, 体外矿化性能也随之提高。综合各方面性能表现, BC-30骨水泥兼具良好的可操作性能、力学性能和体外矿化能力, 是最合适的骨水泥组分。总之, 提高MBGS的质构性能是增强复合骨水泥的可操作性、抗压强度和生物活性的有效方法。     

A novel porous scaffold fabrication technique for epithelial and endothelial tissue engineering

Porous scaffolds have the ability to minimize transport barriers for both two- (2D) and three-dimensional tissue engineering. However, current porous scaffolds may be non-ideal for 2D tissues such as epithelium due to inherent fabrication-based characteristics. While 2D tissues require porosity to support molecular transport, pores must be small enough to prevent cell migration into the scaffold in order to avoid non-epithelial tissue architecture and compromised function. Though electrospun meshes are the most popular porous scaffolds used today, their heterogeneous pore size and intense topography may be poorly-suited for epithelium. Porous scaffolds produced using other methods have similar unavoidable limitations, frequently involving insufficient pore resolution and control, which make them incompatible with 2D tissues. In addition, many of these techniques require an entirely new round of process development in order to change material or pore size. Herein we describe “pore casting,” a fabrication method that produces flat scaffolds with deterministic pore shape, size, and location that can be easily altered to accommodate new materials or pore dimensions. As proof-of-concept, pore-cast poly(ε-caprolactone) (PCL) scaffolds were fabricated and compared to electrospun PCL in vitro using canine kidney epithelium, human colon epithelium, and human umbilical vein endothelium. All cell types demonstrated improved morphology and function on pore-cast scaffolds, likely due to reduced topography and universally small pore size. These results suggest that pore casting is an attractive option for creating 2D tissue engineering scaffolds, especially when the application may benefit from well-controlled pore size or architecture.     

Preparation and characterization of macroporous chitosan/wollastonite composite scaffolds for tissue engineering

Chitosan/wollastonite composite scaffolds were prepared by a thermally induced phase separation method. The microstructure, mechanical performance and in vitro bioactivity of the composite scaffolds were investigated. The composite scaffolds were macroporous and wollastonite particles were dispersed uniformly on the surface of the pore walls. Scanning electron microscope images of the composite scaffolds demonstrated that the scaffolds had interconnected pores with diameters from 60 to 200 microm. Both the pore size and structure were affected by freezing temperature. The mechanical performance of the composite scaffolds was improved compared to that of pure chitosan scaffolds. The in vitro bioactivity of the scaffolds was evaluated by soaking samples in simulated body fluid and the apatite layer was observed on the surface of the pore walls of the composite scaffolds. Our results suggest that the incorporation of wollastonite into chitosan could enhance both the mechanical strength and the in vitro bioactivity of the resultant composite. The macroporous chitosan/wollastonite scaffolds may be a potential candidate for application in tissue engineering.     

多孔硅酸钙生物陶瓷的制备及体外活性和降解性研究

以聚乙二醇为造孔剂,制备了多孔硅酸钙生物陶瓷.应用本文提供的方法,可制得孔连通性好、气孔率53.7%-73.6%、抗压强度4.9-48.5MPa、大孔孔径200-500μm的多孔陶瓷.研究表明,多孔硅酸钙生物陶瓷的力学强度随造孔剂含量的增加而明显降低,而气孔率则相反.应用模拟体液浸泡实验研究了多孔陶瓷的体外生物活性和降解性.研究表明,样品在模拟体液中浸泡1天表面就全部被碳酸代羟基磷灰石层覆盖住.气孔率为63.1%的样品7天的降解率达7.14%,具有良好的降解性.研究结果显示多孔硅酸钙生物陶瓷有望作为硬组织修复支架材料用.     

Sol‒gel synthesis,properties and protein loading/delivery capacity of hollow bioactive glass nanospheres with large hollow cavity and mesoporous shell

Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug delivery. Herein, novel hollow bioactive glass nanospheres (HBGn) with large hollow cavity and large mesopores in their outer shells were synthesized by a simple and facile one-pot ultrasound assisted sol‒gel method using PEG as the core soft-template. Interestingly, the produced HBGn exhibited large hollow cavity with ~43 nm in diameter and mesoporous shell of ~37 nm in thickness and 7 nm pore size along with nanosphere size around 117 nm. XPS confirmed the presence of Si and Ca elements at the surface of the HBGn outer shell. Notably, HBGn showed high protein loading capacity (~570 mg of Cyto c per 1 g of HBGn) in addition to controlled protein release over 5 d. HBGn also demonstrated a good in vitro capability of releasing calcium (Ca²⁺: 170 ppm) and silicate (SiO₄⁴⁻: 78 ppm) ions in an aqueous medium over 2 weeks under physiological-like conditions. Excellent in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in SBF. A possible underlying mechanism involving the formation of spherical aggregates (coils) of PEG was proposed for the formation process of HBGn.     

Development of cryogenic prototyping for tissue engineering

A major challenge in tissue engineering has been the creation of scaffolds with controlled complex geometries. Rapid prototyping (RP) has the ability to produce complex three-dimensional structures with precise control of pore size, geometry and connectivity. In this paper, a novel technique utilising RP technology for the fabrication of tissue engineering scaffolds is presented. The main advantage of this cryogenic prototyping (CP) technique is the low operating temperatures which will allow the processing of temperature sensitive and bioactive components. Microstructure of CP Chitosan scaffolds fabricated can be controlled by processing parameters, such as the processing temperature. The macrostructure of the scaffolds is controlled by 3D computer aided design (CAD). In addition, in vitro studies with Chitosan CP scaffolds have shown that the scaffold designs are useful in promoting cell infiltration and alignment. Preliminary in vivo studies show encouraging results of cellular infiltration as well as vascularisation.     

介孔硼硅酸盐玻璃微球药物载体的制备及其性能表征

介孔二氧化硅微粒具有化学稳定性好、比表面积大和表面易修饰等特点, 作为药物载体具有良好的应用前景, 但其缺乏生物活性且生物降解缓慢等在一定程度上限制了它的应用领域。为克服这些缺陷, 寻找合适的药物载体已成为重要研究方向。与纯二氧化硅相比, 硼硅酸盐玻璃具有良好的生物活性和更高的降解速率。基于此, 本研究尝试合成介孔硼硅酸盐玻璃微球(MBGMs), 并表征了其在负载和释放抗肿瘤药物盐酸阿霉素(DOX)过程中的载体特性和材料降解引发的各种功能性离子的释放行为。结果表明BMGMs具有约25 mg/g的DOX负载量,引入硼不仅可以调控MBGMs的化学活性和降解速率, 而且较高硼含量的MBGMs可促进酸性条件下的药物释放, 具有一定的酸性响应性。此外, MBGMs可在模拟体液中释放SiO₄^4-、BO₃^3-和Ca²⁺等有益骨组织生长的功能性离子, 并诱导生成羟基磷灰石, 具备良好的离子缓释能力和体外矿化活性。因此, MBGMs作为一种新颖的药物载体材料, 既可作为药物和功能离子的双重负载, 又具有良好的生物活性和降解特性, 在病理性骨缺损修复领域具有良好的应用前景。     

骨组织工程用硅胶/掺锶β-磷酸三钙/硫酸钙复合多孔支架的制备与性能研究

以掺锶β-磷酸三钙/硫酸钙为原料,利用搅拌喷雾干燥法制备出掺锶β-磷酸三钙/硫酸钙复合小球,再将硅胶与制备的复合小球复合,通过在模具中堆垛聚集的方法,制备出硅胶/掺锶β-磷酸三钙/硫酸钙复合生物支架。采用XRD,SEM,FT-IR等方法分析制得复合多孔支架的成分、形貌以及结构特征,并研究复合生物支架的降解性、孔隙率、力学性能和细胞毒性等。结果表明:该复合多孔生物支架具有一定的不规则孔洞结构,小球与小球之间的孔隙约为0.2~1mm,而每个小球上也有大量的微孔,孔径在50~200μm之间,且平均孔隙率达到62%,基本能满足骨组织工程支架对孔隙率的要求;该复合多孔支架无细胞毒性,其降解周期约为80天,抗压强度约为0.1MPa,因此该支架在非承重骨组织修复方面具有良好的应用前景。     

Preparation and characterization of bioactive collagen/wollastonite composite scaffolds

A novel biodegradable collagen/wollastonite composite was prepared as three-dimensional scaffolds by freeze-drying method. Scanning electron microscope (SEM) micrographs of scaffolds showed a continuous structure of interconnected pores, and pore size was about 100 m. The tensile strength of the scaffolds was improved by incorporation of wollastonite and the in vitro bioactivity of the scaffolds was evaluated by examining the hydroxyapatite (HA) deposition on their surface in simulated body fluid (SBF). After soaking in SBF for 7 days, collagen reconstituted to fibers and HA nodules formed on collagen fibers. The result suggests that the incorporation of wollastonite could improve the mechanical strength and the in vitro bioactivity of the composite. The scaffolds could be a potential biomaterial for bone tissue engineering.