生物复合纳米纤维作为组织工程支架材料的研究进展

由有机-有机和无机-有机材料混合电纺制备的生物复合纳米纤维具有优良的仿生性和生物活性,它们在软、硬组织工程支架领域中具有广泛的应用前景。本文综述了这两种生物复合纳米纤维作为组织工程支架的研究进展,并对研究中存在的问题和今后研究的方向进行了讨论。     

纤维素组织工程支架的研究进展

纤维素具有良好的生物相容性和可降解性,在生物组织工程领域作为支架材料的研究近年来受到研究者的关注。文章介绍了组织工程支架的性能要求,以及纤维素、细菌纤维素用于组织工程支架的研究现状。针对组织工程支架的分子设计、纳米化趋势,提出了纳米纤维素纤维用于组织工程支架的设想。并综述了纳米纤维素纤维制备的最新研究进展,预测了未来纤维素组织工程支架的发展趋势及前景。     

静电纺丝制备有序纳米纤维的研究进展

2000年以来,静电纺丝技术成为高分子材料和纳米技术研究领域的一个新的热点。综述了近年来采用静电纺丝法制备有序纳米纤维的研究进展,并讨论了有序纳米纤维的潜在应用。     

组织工程支架材料的研究进展

组织工程支架材料在组织工程研究中起中心作用，它不仅为特定的细胞提供结构支撑怍用，而且还起到模板作用，引导组织再生和控制组织结构。因此，寻找一种既有良好生物相容性和生物降解性又具有特定形状和连通三维多孔结构的支架材料是组织工程的一个重要方面。本文主要对组织工程中常用支架材料的研究进展进行了综述．并对组织工程支架材料目前存在的问题作了分析以及对其发展趋势进行了展望。     

PHBV共混物纤维制备组织工程支架的研究

利用聚羟基丁酸酯/聚羟基戊酸酯(PHBV)共混材料为基质,通过熔融纺丝、压片成型以及纤维熔结工艺,制得了组织工程用三维多孔支架。研究了PHBV共混材料的吸水率与溶胀比以及支架的熔结温度。结果表明:PHBV共混材料的吸水率较PHBV大为提高,有利于改善PHBV材料的亲水性。其溶胀比较低有助于保持组织工程支架的尺寸稳定性。PHBV共混物纤维的最佳熔结温度在130～140℃范围。采用压片成型/纤维熔结法可制得孔径在300~500μm之间、贯通性好的三维立体支架。降解实验表明:支架材料的降解会引起pH值的微弱下降,支架材料的降解速率较慢。     

光学复合纳米纤维的研究进展

由于单一纳米纤维材料逐渐呈现出性能缺陷,复合纳米纤维材料受到人们的关注。光学复合纳米纤维因其独特的光学特性被广泛深入地研究。光学复合纳米纤维包括电化学发光复合纳米纤维和光致发光复合纳米纤维。综合近年来国内外光学复合纳米纤维光学特性的相关研究,介绍了应用广泛的联吡啶钌(Ru(bpy)2+3)、稀土元素、量子点及晶格或发光中心吸收发光的光学复合纳米纤维的制备、材料特点及应用。指出光学复合纳米纤维材料面临的一些亟需解决的问题,纳米纤维的光电特性的进一步提高,光学复合纳米纤维的应用领域的进一步扩大等;光学复合纳米纤维在生物传感、芯片实验室、纳米器件及医学等领域的应用前景广阔。     

纳米纤维的研究进展

本文介绍了纳米纤维的定义、应用和发展现状及最新成果,讨论了纳米纤维的制备方法,包括传统纺丝方法：静电纺丝法、复合纺丝法和分子喷丝板法;纳米改性纤维的制备方法：聚合复合法,共混纺丝,后整理技术等。     

组织工程支架材料研究进展

组织工程支架材料在组织工程研究中起中心作用，不仅为特定的细胞提供结构支撑作用，而且还起到模板作用，引导组织再生和控制组织结构。寻找一种既有良好生物相容性和生物降解性又具有特定形状和连通三维多孔结构的支架材料是组织工程的重要方面。本文概述了几种常用的组织工程支架材料，并对组织工程支架材料目前存在的问题作了分析、对其发展趋势进行了展望。     

三种不同溶剂静电纺丝素纳米纤维的研究进展

静电纺丝素纳米纤维支架材料在组织工程领域具有广阔的应用前景。本文综述了三种不同溶剂静电纺丝素纳米纤维支架材料及其在组织工程领域的研究进展。     

壳聚糖纳米纤维的制备及其在生物医学领域的应用

本文主要讨论了壳聚糖纳米纤维的制备及在生物医学领域的应用。壳聚糖纳米纤维主要采用静电纺丝的方法制备,为改善壳聚糖的可纺性将其与其他高分子进行混合纺丝;壳聚糖纳米纤维的应用主要集中在医用敷料、组织支架、仿生细胞质基质等方面。通过对壳聚糖纳米材料的制备及应用的文献综述,对壳聚糖纳米材料进行了展望。     

微观结构与组织工程丝素支架研究进展

丝素蛋白因其具有良好的生物相容性、生物可降解性以及卓越的力学性能而被广泛应用于组织工程。为了促进丝素支架更利于细胞的黏附和增殖、促进新的细胞外基质生成、组织向内生长以及利于营养物质及代谢产物的运输等,丝素支架微观结构的构建仍是组织工程的一个重大挑战。本文着重围绕丝素支架的微观结构展开,介绍了多孔结构、纤维结构、多孔-纤维结构和水凝胶结构近年来在组织工程中的应用,从不同支架结构制备方法及功能方面并结合作者实验相关工作对比分析了不同支架结构的优势和存在的问题以及对细胞的影响,指出应从分子水平及原子水平上研究天然组织的结构来精准、有效地体外模拟构建组织工程丝素支架。     

组织工程支架材料及制备方法研究现状

组织工程支架已经广泛应用于皮肤、软骨、心血管、心脏等各种组织的修复中.组织工程材料分为天然材料和合成材料两大类,均需要具备良好的生物相容性.组织工程支架的制备方法主要有相分离、冷冻干燥、发泡、颗粒浸出、静电纺丝、3D打印等.现对组织工程支架所用到的材料、制备方法以及组织工程支架的应用进行综述.     

Hierarchical bioceramic scaffold for tissue engineering: A review

Bioceramic scaffolds have a promising application in bone-tissue engineering field. However, bioceramic scaffolds exhibit low fracture toughness; hence, to overcome this problem, hierarchical bioceramic scaffold or bioceramic scaffolds coated with polymer are produced. Starting with the fundamental requirements for bioceramic scaffold, this article provides detailed information on recent developments of method to produce porous bioceramics scaffold and hierarchical bioceramic scaffold. Chemical modifications to enhance interfacial adhesion and formation of interpenetrating network structures between the bioceramic scaffold and the natural polymer layer are discussed in this article. Areas of future research are highlighted at the end of this review.     

Biomimetic porous collagen/hydroxyapatite scaffold for bone tissue engineering

Bone defect and osteochondral injury frequently occur due to diseases or traumatism and bring a crucial challenge in orthopedics. The hybrid scaffold has shown promise as a potential strategy for the treatment of such defects. In this study, a novel biomimetic porous collagen (Col)/hydroxyapatite (HA) scaffold was fabricated through assembling layers of Col containing gradual amount of HA under the assistance of “iterative layering” freeze‐drying process. The scaffold presents a double gradient of highly interconnected porosity and HA content from top to bottom, mimicking the inherent physiological structure of bone. Owing to the biomimetic structure and component, significant increase of cell proliferation, alkaline phosphatase activity, and osteogenic differentiation in vitro was observed, illustrating potential application of the excellent Col/HA scaffold as a promising strategy for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45271.     

Synthesis of unsaturated polyphosphoester as a potential injectable tissue engineering scaffold materials

Polyphosphoester is a kind of biodegradable polymer with excellent biocompatibility and have been used in drug delivery, tissue engineering, and other bioapplications. A novel unsaturated polyphosphoester (UPPE) based on bis(1,2‐propylene glycol) fumarate (BPGF) and ethyl dichlorophosphate was synthesized by polycondensation reaction, and crosslinkable double bonds was introduced into the resulting polymer through the fumarate groups. NMR results indicate that there are three possible bonding models in polyphosphoester because of three isomers of BPGF. The GPC results express that increase in polymerization time leads to high molecular weight of polyphosphester and narrow distribution of molecular weight. After 18 h of polymerization reaction, the molecular weight reached to 5956 g mol^?1 and the polydispersity index was 1.12. The UPPE was soluble in N‐vinyl pyrrolidone and easily crosslinked by free‐radical polymerization. At the constant temperature (37°C), the maximum temperature due to heat release during crosslinking reaction varied from 41.1°C to 82.30°C and the setting time was between 1.95 and 10.28 min, according to different formulas. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3095–3101, 2006     

Preparation and characterization of porous scaffold composite films by blending chitosan and gelatin solutions for skin tissue engineering

Biodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. In the present investigation blends of chitosan and gelatin with various compositions were produced as candidate materials for biomedical applications. Fourier transform infrared spectral analysis showed good compatibility between these two biodegradable polymers. The composite films showed improved tensile properties, highly porous structure, antimicrobial activities, low water dissolution, low water uptake and high buffer uptake compared to pure chitosan or gelatin films. These enhanced properties could be explained by the introduction of free ? OH, ? NH₂ and ? NHOCOCH₃ groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (? NH³⁺) of the chitosan and the carboxylate ions (? COO^?) of the gelatin. Scanning electron microscopy images of the blend composite films showed homogeneous and smooth surfaces which indicate good miscibility between gelatin and chitosan. The leafy morphologies of the scaffolds indicate a large and homogeneous porous structure, which would cause increased ion diffusion into the gel that could lead to an increase in stability in aqueous solution, buffer and temperature compared to the gelatin/chitosan system. In vivo testing was done in a Wistar rat (Rattus norvegicus) model and the healing efficiencies of the scaffolds containing various compositions of chitosan were measured. The healing efficiencies in Wistar rat of composites with gelatin to chitosan ratios of 10:3 and 10:4 were compared with that of a commercially available scaffold (Eco‐plast). It was observed that, after 5 days of application, the scaffold with a gelatin to chitosan ratio of 10:3 showed 100% healing in the Wistar rat; however, the commercial Eco‐plast showed only a little above 40% healing of the dissected rat wound. Copyright © 2012 Society of Chemical Industry     

Incorporation of graphene oxide and calcium phosphate in the PCL/PHBV core-shell nanofibers as bone tissue scaffold

Bone tissue scaffolds should have both desired mechanical stability and cell activities including biocompatibility, cell differentiation, and maturation. Also, suitable mineralization is another key factor for these materials. Hence, in current work, in order to achieve a scaffold with desired mechanical and bioactivity properties, core-shell nanofibers based on the polycaprolactone and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with different concentration of graphene oxide (GO) (0.5, 1, and 1.5 wt%) and calcium phosphate (CP) (1 and 3 wt%) were prepared to utilize as bone scaffold. Microstructure of nanofibers observed by field emission scanning electron microscope (FE-SEM) and results exhibited that the most of nanofibers had 270–500 nm diameter. Attenuated total reflectance Fourier transform infrared spectroscopy and energy dispersive X-ray evaluations verified appearance of GO and CP into the electrospun scaffolds (ES). Transmission electron microscopy analysis endorsed core-shell structure of nanofibers. X-ray diffraction study moreover determination of semicrystalline structure, verified presence of GO and CaPO₄ into the nanofibers. Water contact angle demonstrates that, ES2 and ES3 situated in suitable domain of hydrophilicity. Tensile analysis determined that, ES2, ES3, and ES4 had the highest mechanical properties for use as bone scaffold. Cell viability assessment confirmed biocompatibility of scaffold during 7 days. Alkaline phosphatase and alizarin red staining exhibited maturating and differentiating of osteocytes after 21 days seeding on the scaffolds.     

Chitin scaffolds in tissue engineering

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine.     

组织工程多孔支架微管内流场数值模拟

骨支架内部微管结构对营养液和细胞在其内部的流动有着非常重要的影响。利用流体计算软件Fluent对不同尺寸的人工骨微管结构内部营养液和细胞的流动状况进行了数值模拟,得到了不同几何结构骨支架内部流场的速度和压力分布图。结果表明,从进口到出口,主管道内流体流速随管道的深入不断减小。上端浮克曼管中流体流速比下端浮克曼管中流体流速高,但是比同一高度主管道内流体流速低。哈佛氏管与第一行浮克曼管交叉处下端的哈佛氏管内存在流动缓慢区,第三行浮克曼管与哈佛氏管交叉处开始,流体速度不断增大。随浮克曼管长度的增加,上端哈佛氏管中流体流动的缓慢区减小;随浮克曼管直径的增加,浮克曼管中的流速有所增加,并且各微管中流体的流速更为均匀;随浮克曼管与主管道夹角的增加,骨支架各微管内流体流速更加均匀,利于细胞和营养液在各管道的输运。本数值模拟范围内,最佳骨支架结构参数为浮克曼管长度3mm,直径0.6mm,浮克曼管与主管道夹角90°。