聚乳酸纳米纤维仿生组织工程支架的制备及对细胞的作用研究

发布时间：2018-06-13 20:37

本文选题：支架 + 纳米纤维　；参考：《华南理工大学》2014年博士论文

【摘要】：组织工程（Tissue engineering，TE）的研究旨在构建具有生物活性和功能的人工组织/器官以替代体内受损、病变或老化的组织/器官。模拟目标组织/器官细胞外基质（Extracelluar matrix，ECM）结构的仿生支架在TE研究中起着非常关键的作用。人体周围神经（Peripheral nerve system，PNS）、肌腱等组织的ECM呈纵向排列多通道（Multiple-channeled，MC）结构，通道壁由沿轴向取向的胶原纳米纤维（Nanofiber，NF）组成。一直以来，，制备具有上述结构特征的TE支架面临诸多困难和挑战。为解决该难题，本课题制备了一种由玻璃管、针及间隔物组成的、用来制备MC支架的模具。利用该模具，本研究将热致相分离（Thermally-induced phase separation，TIPS）技术和注射模塑技术相结合，制备了聚左旋乳酸（Poly（L-lactic acid），PLLA）MC NF支架。通过改变模具组件的组合方式、尺寸大小和/或PLLA浓度可以控制支架宏观（mm及以上）、亚微观（μm）和微观（nm）尺度的形貌结构。改变PLLA浓度还能调控支架的力学性能。该支架有效解决了当前非NF MC支架结构方面存在的壁厚过大、壁孔结构不合理及力学性能差等缺陷。本课题还设计了一套以冰水为冷却介质的低温拉伸装置，利用该装置可对PLLA/四氢呋喃物理凝胶进行拉伸，制备取向NF（Aligned-nanofiber，ANF）支架。研究发现，PLLA ANF支架的取向度、机械性能随凝胶拉伸倍率的提高而提高，而NF的形貌结构、热学性能几乎不受影响。该工艺的机理为凝胶拉伸导致其内部聚合物富相（Polymer-rich phase，PR）微区沿外力方向发生不可逆滑移，形变的PR微区在后续工序中被固定并转变为ANF。该工艺解决了TIPS技术不能控制NF定向排列的不足，为制备MC ANF支架提供了可能性。本课题考察了上述仿生支架的形貌结构对蛋白吸附、细胞黏附、形态及功能的影响，结果发现PLLA MC NF支架能大量且均匀地吸附蛋白质，有效促进细胞黏附，为细胞提供更好的生长微环境，PLLA ANF支架可使黏附的细胞沿着纤维排列方向取向伸展和排列，具有一定的诱导和调控细胞行为及功能的能力。本课题的研究结果表明所制备的PLLA仿生支架具有促进PNS、肌腱等组织修复和再生的潜力，可应用于这些组织的TE研究中。
[Abstract]:Tissue engineering study aims to construct artificial tissues / organs with biological activity and function to replace damaged, diseased or aging tissues / organs in vivo. Biomimetic scaffolds simulating extracellular matrix ECM (ECM) structure of target tissue / organ play a key role in te research. The nerve of peripheral nerve, tendon and other tissues of human peripheral nerve are arranged longitudinally in Multiple-channel (MC) structure, and the channel wall is composed of collagen nanofilament (Nanofiberus NFS) which is oriented along the axis. The preparation of te scaffolds with these structural characteristics has been facing many difficulties and challenges. In order to solve this problem, a mold composed of glass tube, needle and spacer was prepared to fabricate MC scaffold. Using the mould, the thermo-induced phase separation (TIPS) technology and the injection molding technology were used to prepare poly (L-lactic acidactic) PLLAMC NF scaffolds. By changing the combination mode of die assembly, size and / or PLLA concentration, the shape and structure of the support can be controlled on the scale of macroscopes and above, submicroscopic (渭 m) and microcosmic (渭 m). The mechanical properties of the scaffold can also be regulated by changing the concentration of PLLA. The structure of the non-NF MC scaffold has many defects, such as too large wall thickness, unreasonable wall hole structure and poor mechanical properties. A low temperature drawing device with ice water as cooling medium was also designed in this paper. PLLA / tetrahydrofuran physical gel could be stretched by this device and oriented NFA ligned-nanofiberine ANFS scaffold could be prepared. It was found that the orientation degree and mechanical properties of PLLA ANF scaffolds increased with the increase of gel tensile ratio, while the morphology and thermal properties of NF were almost unaffected. The mechanism of this process is that the internal polymer rich phase Polymer-rich phase PRA region is irreversibly slippage along the direction of external force, and the deformed PR microregion is fixed and converted to ANFin in the subsequent process. This process solves the problem that tips technology can not control NF directional arrangement and provides the possibility for the preparation of MC ANF scaffolds. The effects of the morphology and structure of the bionic scaffold on protein adsorption, cell adhesion, morphology and function were investigated. The results showed that PLLA MC NF scaffold could adsorb protein in a large amount and homogeneously, and promote cell adhesion effectively. The PLLA ANF scaffold provides a better growth microenvironment for the cells to extend and arrange along the fiber arrangement direction, and has the ability to induce and regulate the cell behavior and function to a certain extent. The results show that the PLLA biomimetic scaffolds have the potential to promote the repair and regeneration of tissues such as PNSs and tendons, and can be used in the te study of these tissues.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R318.08

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