乙烯-醋酸乙烯酯/羟基磷灰石/聚酰胺软骨及骨一体化修复材料的制备与表征

采用共混法和相分离法制备了纳米羟基磷灰石(nHA)和聚酰胺(PA66)复合支架材料。nHA在PA66基质中分布均匀。复合支架材料孔径50～500μm,孔隙率为80.9%。将乙烯-醋酸乙烯脂(EVA)通过热注塑方法在支架材料表面涂覆形成双层结构的软骨及骨一体化修复材料,EVA层用于软骨修复,下层nHA-PA66支架进行缺损骨修复和固定。EVA和nHA-PA66的力学性能测试显示,EVA的拉伸和压缩模量分别为(0.87±0.02)MPa和(9.44±0.46)MPa,多孔支架的压缩强度和模量分别为(0.9±0.02)MPa和(15.2±0.69)MPa。摩擦测试结果表明,EVA摩擦系数为0.23。     

用于软骨和软骨下骨修复的纳米羟基磷灰石/聚乙烯醇/聚酰胺66功能梯度材料的制备和表征

利用反复冷冻-解冻法和相分离法,制备出用于软骨和软骨下骨修复的纳米羟基磷灰石(nHA)/聚乙烯醇(PVA)/聚酰胺(PA66)功能梯度材料。研究表面层PVA的力学性能和摩擦学性能,及软骨下骨nHA/PA66(m(HA)∶m(PA66)=1∶1)支架的力学性能及生物学性能。结果表明PVA拉伸强度为1.938MPa,平均摩擦系数在生理盐水及代血浆润滑条件下分别为0.076和0.085;nHA/PA66复合多孔支架孔隙率为80.93%,孔径为50～500μm,压缩强度和压缩模量分别为0.88和15.21MPa,且具有良好的生物相容性。     

微囊化壳聚糖/纳米羟基磷灰石/胶原/聚乳酸复合材料

以多聚磷酸钠(TPP)为交联剂,采用乳化交联法制备了牛血清白蛋白(BSA)壳聚糖控释微球(CMs)。将微球与纳米羟基磷灰石/胶原(nHAC)、聚乳酸(PLA)按不同比例混合,采用热致分相法制备了CMs/nHAC/PLA复合支架材料。利用扫描电镜、激光粒度分析仪、压汞仪和力学性能测试仪考察了微球与复合支架的性能。结果表明：所制备的壳聚糖微球形态良好,呈规则球形,粒径主要分布在20～50μm;随 BSA 初始用量的增加,微球的载药量从0.78%增大到2.74%,但包封率从86.9%下降到78.4%;控制CMs用量不超过PLA 质量的30%,则可保证微球在CMs/nHAC/PLA中的均匀分布,此时复合材料的孔径主要分布在100～200μm,孔隙率不低于83.1%,压缩强度在1～2 MPa。这种复合支架材料可望作为人体非承重部位的植入骨修复体和组织工程支架使用。     

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。     

可缓释药物的明胶/磷酸钙骨水泥复合组织工程支架材料

采用向孔隙中灌注含聚乳酸聚乙醇酸共聚物（PLGA）载药微球的明胶溶液的方法制备了具有药物缓释功能的明胶/磷酸钙骨水泥复合组织工程支架。用扫描电子显微镜观察了微球和支架的形貌特征,用万能材料试验机测定了支架材料的抗压强度,用紫外-可见分光光度计分析了复合支架的释药率。结果表明,灌注明胶对多孔磷酸钙骨水泥支架起到显著的增强作用,抗压强度达2.42 MPa。复合支架携载硫酸庆大霉素, 具有良好的药物缓释功能,缓释时间可达30天以上,使支架在修复骨缺损的同时能消除炎症反应,成为一种集骨修复和治疗于一体的新型组织工程支架材料,具有良好的应用前景。      

骨软骨组织工程仿生梯度支架研究进展

骨软骨缺损是导致关节发病和残疾的重要原因,骨软骨组织工程是修复骨软骨缺损的方法之一。骨软骨组织工程方法涉及仿生梯度支架的制造,该支架需模仿天然骨软骨组织的生理特性（例如从软骨表面到软骨下骨之间的梯度过渡）。在许多研究中骨软骨仿生梯度支架表现为离散梯度或连续梯度,用于模仿骨软骨组织的特性,例如生物化学组成、结构和力学性能。连续型骨软骨梯度支架的优点是其每层之间没有明显的界面,因此更相似地模拟天然骨软骨组织。到目前为止,骨软骨仿生梯度支架在骨软骨缺损修复研究中已经取得了良好的实验结果,但是骨软骨仿生梯度支架与天然骨软骨组织之间仍然存在差异,其临床应用还需要进一步研究。本文首先从骨软骨缺损的背景、微尺度结构与力学性能、骨软骨仿生梯度支架制造相关的材料与方法等方面概述了离散和连续梯度支架的研究进展。其次,由于3D打印骨软骨仿生梯度支架的方法能够精确控制支架孔的几何形状和力学性能,因此进一步介绍了计算仿真模型在骨软骨组织工程中的应用,例如采用仿真模型优化支架结构和力学性能以预测组织再生。最后,提出了骨软骨缺损修复相关的挑战以及骨软骨组织再生未来研究的展望。例如,连续型骨软骨仿生梯度支架需要更相似地模拟天然骨软骨组织单元的结构,即力学性能和生化性能的过渡更加自然地平滑。同时,虽然大多数骨软骨仿生梯度支架在体内外实验中均取得了良好的效果,但临床研究和应用仍然需要进行进一步深入研究。     

CPP/PLLA软骨组织工程支架复合材料初步研究

采用溶媒投放、颗粒滤取技术制备出CPP/PLLA软骨组织工程支架复合材料,测试了该复合材料的物理力学性能和降解性能。研究结果表明,CPP/PLLA软骨组织工程支架复合材料具有高的孔隙率(90%)、良好的生物降解性能和物理力学性能,以及三维连通、微孔、网状微观结构,故该复合材料有希望成为软骨组织工程支架材料之一。     

β-磷酸三钙/聚L-乳酸与大鼠骨膜成骨细胞复合骨修复材料的研究

采用溶液浇铸-模压成型-沥滤方法制备了β-TCP/PLLA多孔支架材料, 将支架材料与大鼠骨膜成骨细胞复合获得新型组织工程骨修复材料. 通过抗压强度及压缩模量的表征研究了支架材料的力学性能; 采用SEM观测、MTT法、碱性磷酸酶活性及骨钙素分泌量检测细胞复合材料的体外成骨特性; 通过裸鼠肌袋种植, 以组织学方法评价细胞复合材料的异位成骨能力. 结果表明: β-TCP/PLLA多孔支架材料孔隙率可调, 孔径为100～00μm, 孔道相互贯通; 材料抗压强度和压缩模量随孔隙率的增大而降低, β-TCP复合PLLA后材料的力学性能高于同孔隙率的纯PLLA多孔材料; 复合支架材料适宜骨膜成骨细胞粘附和生长, 无细胞毒性; 骨膜成骨细胞复合β-TCP/PLLA支架材料的体外成骨特性良好, 且具有体内异位成骨能力.     

壳聚糖-明胶/APTES改性生物活性玻璃复合支架的制备工艺

为改善生物活性玻璃与高分子之间的相容性,利用 APTES改性生物活性玻璃(SBG),通过冷冻干燥法制备出用于骨和软骨组织工程的壳聚糖-明胶/APTES改性生物活性玻璃(CS 2Gel/ SBG)仿生型复合多孔支架,并对其孔隙率、力学性能和显微形貌进行了表征;探讨了各组分不同含量、交联剂和冷冻温度对CS-Gel/SBG复合支架孔隙率、力学性能和显微观结构的影响。研究表明,当SBG和CS-Gel的含量分别为70和40 g·L-1,用EDC和NHS交联,-50℃急冻2h后,又在-15℃ 下冷冻10h,最后真空冷冻干燥,制备出孔隙分布均匀、孔隙率达到90 %以上、三维连通的复合多孔支架。     

锶锌共掺杂磷酸八钙微球制备及其骨修复性能

本文研究了锶、锌共掺杂磷酸八钙多孔微球(Sr/Zn-OCP)的制备及其体内成骨生物学效应。实验运用湿化学合成工艺制备了粒径为105μm、280μm和500μm三种单分散微球颗粒材料,然后再考察微球材料对大白兔股骨缺血性坏死骨缺损的再生修复效应以及微球颗粒度对缺损修复效率的影响规律,运用理化表征与组织学分析考察了微球的微结构和骨组织修复特性。结果显示,利用低浓度聚丙烯酸可以诱导多层化尺度均一的Sr/Zn-OCP多孔微球颗粒形成,并且通过改变反应溶液的搅拌速率可以改变微球的尺度大小;同时,三种粒度微球堆积体均可见骨缺损内新骨再生,但是粒度最大的500μm微球修复骨缺损效率最高,在微球植入术后10、16周时新骨再生率达到37%和62%。以上研究结果表明多孔性Sr/Zn-OCP微球具有优良的生物活性效应,在解决病理性骨缺损再生修复方面具有良好应用价值。     

Schwann cell-seeded scaffold with longitudinally oriented micro-channels for reconstruction of sciatic nerve in rats

To provide a more permissive environment for axonal regeneration, Schwann cells (SCs) were introduced into a collagen-chitosan scaffold with longitudinally oriented micro-channels (L-CCH). The SC-seeded scaffold was then used for reconstruction of a 15-mm-long sciatic nerve defect in rats. The axonal regeneration and functional recovery were examined by a combination of walking track analysis, electrophysiological assessment, Fluoro-Gold retrograde tracing, as well as morphometric analyses to both regenerated axons and target muscles. The findings showed that SCs adhered and migrated into the L-CCH scaffold and displayed a longitudinal arrangement in vitro. Axonal regeneration as well as functional recovery was in the similar range between SCs-seeded scaffold and autograft groups, which were superior to those in L-CCH scaffold alone group. These indicate that the SCs-seeded L-CCH scaffold, which resembles the microstructure as well as the permissive environment of native peripheral nerves, holds great promise in nerve regeneration therapies.     

Fabrication of tissue engineered PCL scaffold by selective laser-sintered machine for osteogeneisis of adipose-derived stem cells

Polycaprolactone (PCL) is a bioresorbable polymer with potential applications for bone and cartilage repair. In this work, three-dimensional (3D) and porous PCL scaffolds were designed and fabricated via selective laser sintering (SLS). The aim of this study was to evaluate the osteogenic potential of porcine adipose-derived stem cells (pASCs) in a laser-sintered PCL (lsPCL) scaffold. The character of the lsPCL scaffold was evaluated. The pore size and the microstructure were observed by SEM. The pASCs were harvested and isolated from pig inguinal area. Then, the lsPCL scaffold was seeded with ASCs and cultured in osteogenic medium for 0 and 14 days. Cell proliferation was measured by MTS. Alkaline phosphatase activity (ALP) was detected using biochemical methods. SEM was used to observe the interaction between scaffold and cell. An energy dispersive spectrum (EDS) was used to analyze the mineralization in each group. Porosity was around 83%; pore size was around 300–400 µm. Both MTS and ALP showed significant increase after subcultivation in osteogenic medium for 14 days. SEM detailed that the pASCs cell can attach well to the lsPCL scaffold. The energy dispersive spectrum (EDS) also demonstrated calcium deposits around pASCs after osteo-induction for 14 days. In contrast, no mineralization was found around ASCs after osteo-induction of 0 days. In conclusion, the laser-sintered PCL is a suitable scaffold for the proliferation of ASCs. The ASCs were also well differentiated into osteoblasts in the 3D, porous, laser-sintered PCL scaffold.     

Biocompatible biodegradable polycaprolactone/basil seed mucilage scaffold for cell culture

In this study, a polymer obtained from the basil seed mucilage (BSM) in combination with polycaprolactone (PCL), was used in the 2D scaffold production process for cell culture. First, combinations of two polymers with different ratios and concentrations were prepared and electrospun. Among these samples, a sample with a BSM/PCL ratio of 2/3 was used to perform different tests due to its fibre uniformity and appropriate diameter. The Fourier transform infrared spectrometer test was carried out to chemically analyse the scaffold, the X‐ray diffraction test to determine the crystallinity of the scaffold, and the contact angle test to determine the hydrophilicity of the scaffold. The strength, porosity, and degradation percentage of the scaffold were also studied. With appropriate conditions of the scaffold for cell culture determined, Vero epithelial cells were cultured on the scaffold. Results obtained from cell culture indicated that the adhesion of the scaffold was suitable for the appropriate growth cells.Inspec keywords: adhesion, porosity, hydrophilicity, tissue engineering, X‐ray diffraction, electrospinning, cellular biophysics, contact angle, biodegradable materials, biomedical materials, polymer blends, Fourier transform infrared spectraOther keywords: X‐ray diffraction test, contact angle test, cell culture, biocompatible biodegradable scaffold, polycaprolactone‐basil seed mucilage scaffold, Fourier transform infrared spectrometer test, scaffold hydrophilicity, Vero epithelial cells, scaffold crystallinity, 2D scaffold production process     

A silk fibroin/chitosan scaffold in combination with bone marrow-derived mesenchymal stem cells to repair cartilage defects in the rabbit knee

Bone marrow-derived mesenchymal stem cells (BMSCs) were seeded in a three-dimensional scaffold of silk fibroin (SF) and chitosan (CS) to repair cartilage defects in the rabbit knee. Totally 54 rabbits were randomly assigned to BMSCs + SF/CS scaffold, SF/CS scaffold and control groups. A cylindrical defect was created at the patellofemoral facet of the right knee of each rabbit and repaired by scaffold respectively. Samples were prepared at 4, 8 and 12 weeks post-surgery for gross observation, hematoxylin–eosin and toluidine blue staining, type II collagen immunohistochemistry, Wakitani histology. The results showed that differentiated BMSCs proliferated well in the scaffold. In the BMSCs + SF/CS scaffold group, the bone defect was nearly repaired, the scaffold was absorbed and immunohistochemistry was positive. In the SF/CS scaffold alone group, fiber-like tissues were observed, the scaffold was nearly degraded and immunohistochemistry was weakly positive. In the control group, the defect was not well repaired and positive immunoreactions were not detected. Modified Wakitani scores were superior in the BMSCs + SF/CS scaffold group compared with those in other groups at 4, 8 and 12 weeks (P < 0.05). A SF/CS scaffold can serve as carrier for stem cells to repair cartilage defects and may be used for cartilage tissue engineering.     

Comparison of morphology and biocompatibility of acellular nerve scaffolds processed by different chemical methods

To investigate the morphological differences among acellular rat nerve scaffolds processed by different chemical methods and compare the biocompatibility between rat nerve grafts processed by different chemical methods and rat adipose-derived stem cells in vitro. Acellular rat sciatic nerve scaffolds processed by two different chemical methods (the Sondell method and the optimized method) and normal rat sciatic nerves were used as control. The structure and components of nerve scaffold were observed under microscopy, the degrees of decellularization and demyelination of nerve scaffold and integrity of nerve fiber tubes were assessed. The rat adipose-derived stem cells growth and adherence on scaffold were studied by scanning electron microscopy, the activity and adhesive ratio of rat adipose-derived stem cells in the nerve scaffold were compared. The basal lamina tubes and the extracellular matrix in the epineurium and perineurium in the nerve graft of optimized method were better preserved than the nerve graft of the Sondell method. After co-cultured with scaffolds, the difference of cell activity between three groups (two cell–scaffold combinations and control group) at the same observation time were not statistically significant (P > 0.05),the adhesive ratio of rat adipose-derived stem cells in the scaffold of the optimized method was better than that of the Sondell method. The scaffold of the optimized method is more effective than the scaffold of the Sondell method for peripheral nerve tissue engineering.     

3D printing of hydroxyapatite scaffolds with good mechanical and biocompatible properties by digital light processing

Hydroxyapatite is a scaffold material widely used in clinical repair of bone defects, but it is difficult for traditional methods to make customized artificial bone implants with complicated shapes. 3D printing biomaterials used as personalized tissue substitutes have the ability to promote and enhance regeneration in areas of defected tissue. The present study aimed at demonstrating the capacity of one 3D printing technique, digital light processing (DLP), to produce HA scaffold. Using HA powder and photopolymer as raw materials, a mixture of HA mass ratio of 30 wt% was prepared by viscosity test. It was used for forming ceramic sample by DLP technology. According to differential scanning calorimetry and thermal gravity analysis, it was revealed that the main temperature range for the decomposition of photopolymer was from 300 to 500 °C. Thus, the two-step sintering process parameters were determined, including sintering temperature range and heating rate. XRD analysis showed that the phase of HA did not change after sintering. SEM results showed that the grain of the sintered ceramic was compact. The compression model was designed by finite element analysis. The mechanical test results showed that the sample had good compression performance. The biological properties of the scaffold were determined by cell culture in vitro. According to the proliferation of cells, it was concluded that the HA scaffold was biocompatible and suitable for cell growth and proliferation. The experimental results show that the DLP technology can be used to form the ceramic scaffold, and the photopolymer in the as-printed sample can be removed by proper high-temperature sintering. The ceramic parts with good compression performance and biocompatibility could be obtained.     

改性淫羊藿苷共价结合壳聚糖/聚羟基丁酸酯-羟基戊酸酯构建组织诱导型骨修复支架材料

为构建一种诱导型骨修复支架材料,将淫羊藿苷（Ica）经过氨基化改性得到Ica-NH₂,并对Ica-NH₂进行FTIR、XRD和TG-DTA表征。以Ica-NH₂共价结合壳聚糖（CS）为诱导因子添加方式,聚羟基丁酸酯-羟基戊酸酯（PHBV）和CS为基材,经过两相混合急速冷冻/冷冻干燥成型技术制备了Ica-NH₂-CS/PHBV骨组织工程支架。随后,对支架材料进行了SEM、体外药物缓释、力学性能、细胞相容性及细胞增殖评价。结果显示:氨基化改性Ica的FTIR谱图在3 371、3 328 cm-1处出现2个中等强度、尖锐的N—H伸缩振动峰,在1 689 cm-1处出现N—H变角振动峰;XRD谱图显示其衍射增强且整体左移,证明Ica被成功氨基化改性;支架材料显微结构呈网络状串珠状,并均匀分布着3~10 μm的微孔,其体外药物缓释效果良好,力学强度介于硬质骨与松质骨之间,复合细胞培养7 d 后表现出良好的贴附与增殖,且细胞在Ica-NH₂-CS/PHBV支架材料上的增殖增长率显著高于CS/PHBV。研究表明所构建的Ica-NH₂-CS/PHBV支架材料可作为一种良好的诱导型骨修复材料。      

Fabrication and characterization of PCL/gelatin/chitosan ternary nanofibrous composite scaffold for tissue engineering applications

In the present study, we have fabricated a ternary composite nanofibrous scaffold from PCL/gelatin/chitosan, by electrospinning technique, using a solvent system—chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin and chitosan, for tissue engineering applications. Field emission scanning electron microscopy (FE-SEM) was used to investigate the fiber morphology of the scaffold and it was found that the fiber morphology was influenced by the concentrations of PCL, gelatin, and chitosan in polymer solution during electrospinning. X-ray diffraction, Fourier transform infrared, and thermogravimetric (TG) analysis results showed some interactions among the molecules of PCL, gelatin, and chitosan within the scaffold. In-vitro cell culture studies were done by seeding L929 mouse fibroblasts on fabricated composite scaffold, which confirmed the cell viability, high cell proliferation rate, and cell adhesion on composite scaffold as indicated by MTT assay, DNA quantification, and FE-SEM analysis of cell-scaffold construct. Thus, the ternary composite scaffold made from the combination of PCL (synthetic polymer), gelatin, and chitosan (natural polymer) may find potential application in tissue engineering.     

Poly(lactic acid) porous scaffold with calcium phosphate mineralized surface and bone marrow mesenchymal stem cell growth and differentiation

This work aims to modify the surface of a poly(lactic acid) (PLA) porous scaffold with calcium phosphate (CaP) via a simple solution-based technique, and to evaluate the effects of this modification on the responses of rat bone marrow mesenchymal stem cells (rBMMSCs). Under appropriate modification conditions involving stepwise-treatments in the Ca-and-P supersaturated solution under gentle agitation, a thin, poorly crystallized CaP layer was deposited. The BMMSCs derived from adult rats were shown to adhere quite well to the CaP-coated scaffold, and to proliferate actively with culturing time, although some down-regulation was noted with regard to the unmodified PLA scaffold. The osteogenic differentiation of rBMMSCs was significantly higher on the CaP-modified scaffold than on the unmodified scaffold, as confirmed by alkaline phosphatase (ALP) activity. Moreover, the expression of genes associated with bone, including collagen type I, osteopontin and bone sialoprotein, was stimulated better on the CaP-modified PLA scaffold. Based on these results, the currently used CaP-treatment was deemed effective in stimulating the osteogenic development of rBMMSCs on the PLA-based scaffold, and the CaP-treated PLA scaffold may be useful for future bone tissue engineering.     

Preparation of porous biodegradable poly(lactide-co-glycolide)/ hyaluronic acid blend scaffolds: Characterization, in vitro cells culture and degradation behaviors

A series of poly(lactide-co-glycolide) (PLGA)/ hyaluronic acid (HA) blend with different HA composition were used to fabricate scaffolds successfully. The pores of the three dimensional scaffold were prepared by particle leaching and freeze drying. The pore size was about 50–200 μ m and the porosity was about 85%. The characterizations of the scaffold, such as mechanical properties, hydrophilicity and surface morphologies were determined. Mouse 3T3 fibroblast was directly seeded on the scaffolds. The cell adhesion efficiency, cell morphology observed by scanning electron microscopy (SEM) and the degradation behavior of the blend scaffold were evaluated. In summary, the results show that the adhesion efficiency of cells on the PLGA/HA blend scaffold is higher than that on the PLGA scaffold. Moreover, the incorporation of HA in PLGA not only helps to increase the cell affinity but also tends to lead the water and nutrient into the scaffold easily.