本文關(guān)鍵詞： 可降解聚合物 多孔支架 制備 細胞相容性 組織工程　出處：《華南理工大學》2015年博士論文　論文類型：學位論文

【摘要】：可降解聚合物多孔支架是組織工程領(lǐng)域的重要研究方向之一,在組織工程中起著關(guān)鍵的作用。人工合成可降解聚合物具有良好的可調(diào)控性,在組織工程領(lǐng)域中具有廣泛的應(yīng)用。但是,人工合成聚合物支架的親水性差且缺乏可供細胞粘附的結(jié)合位點,導(dǎo)致細胞在該類支架上的生長受到了極大的限制。因此,如何制備出細胞相容性良好的可降解多孔支架是目前該領(lǐng)域的研究熱點和難點。靜電紡絲法制備出的纖維支架可以很好的模擬仿生細胞外基質(zhì),本博士論文對如何改進纖維支架的細胞相容性做了深入的研究和探討。首先基于靜電紡絲法,結(jié)合溶液共混和冷凍干燥技術(shù)制備出了聚碳酸亞丙酯(PPC)與天然高分子明膠(gelatin)的納米級復(fù)合纖維支架、熱塑性聚氨酯和氧化石墨烯(GO)復(fù)合纖維小直徑血管支架和具有PPC微米級纖維/殼聚糖(chitosan)納米級纖維并存的層次結(jié)構(gòu)的纖維支架。研究發(fā)現(xiàn)當gelatin在紡絲液中含量高于10%時,gelatin與PPC在紡絲過程中會發(fā)生嚴重相分離導(dǎo)致紡絲液噴濺、纖維粘接等現(xiàn)象的發(fā)生。加入微量醋酸可改善gelatin與PPC的相容性,使得混合液的紡絲過程順利進行得到尺寸均勻的纖維,且加入的gelatin極大的改善了復(fù)合纖維支架的親水性及細胞相容性;通過自主搭建的旋轉(zhuǎn)型收集裝置制備出具有不同GO和PEI含量的TPU/GO,PCL/PEI小直徑血管支架,探討GO和PEI對復(fù)合纖維支架的結(jié)構(gòu)形態(tài)、親水性能的影響,并以人體血管內(nèi)皮細胞為細胞模型,研究了GO和PEI的含量對細胞的生長形態(tài)的影響,發(fā)現(xiàn)了低含量的GO和PEI對細胞的生長有促進作用,而高含量的GO和PEI會導(dǎo)致細胞的死亡;調(diào)節(jié)溶劑的組成和搭建平行板收集裝置制備出了高度取向的PPC微米纖維支架,通過殼聚糖溶液浸潤和冷凍干燥后處理,在PPC微米纖維支架內(nèi)引入chitosan納米纖維,制備出的支架不僅具有微米級纖維和納米級纖維的層次結(jié)構(gòu),而且含有生物相容性良好的chitosan,細胞培養(yǎng)結(jié)果表明該微納纖維復(fù)合結(jié)構(gòu)為細胞的生長提供了適宜的環(huán)境。其次,在靜電紡絲的基礎(chǔ)上,采用聚己內(nèi)酯(PCL)納米纖維作為shish來誘導(dǎo)在稀溶液的聚合物分子在其表面自發(fā)結(jié)晶形成周期性排列的晶片即kebab,制備出具有串晶結(jié)構(gòu)的纖維支架來改變支架的微觀拓撲結(jié)構(gòu),并采用天然聚合物修飾串晶纖維支架以達到在結(jié)構(gòu)上和功能上能夠仿生細胞外基質(zhì)中膠原纖維的目的。分別研究了shish的組成,kebab溶液的組成對形成的串晶結(jié)構(gòu)的影響。研究發(fā)現(xiàn):采用聚己內(nèi)酯(PCL)/納米級羥基磷灰石(n HA)復(fù)合纖維作為shish制備出的串晶結(jié)構(gòu)具有良好的仿生礦物化性能且有利于人體骨肉瘤細胞(MG63)的生長,且使得纖維支架的力學強度得到改善;與77%的醋酸相比,使用PCL溶解度更低的乙酸戊酯作為溶劑配制的稀溶液有利于在PCL納米纖維上形成規(guī)整的kebab;采用化學接枝的方法在PCL串晶纖維支架表面接枝生物相容性好的基質(zhì)膠(matrigel)可改善纖維支架的親水性和細胞相容性。針對在研究中發(fā)現(xiàn)的溶液共混和化學接枝法的缺點和不足,提出chitosan-PCL共聚物在PCL納米纖維表面結(jié)晶來制備支架的新方法,在結(jié)晶過程中,共聚物中的PCL端會在紡絲纖維表面自發(fā)結(jié)晶形成周期性排列的晶片,而共聚物中的殼聚糖則由于PCL纖維的排斥作用而被暴露在外。采用該思路制備出的纖維支架既使得支架具有串晶結(jié)構(gòu)這一獨特的微觀拓撲形態(tài),又使得復(fù)合纖維支架富含殼聚糖單元來提供細胞的結(jié)合位點。研究發(fā)現(xiàn):采用該設(shè)計思路制備出的支架具有良好的親水性、仿生礦物化性能、細胞相容性以及優(yōu)良的成骨能力。最后,為解決靜電紡絲法制備出的纖維支架規(guī)整性不足且難以制備成特定形狀的多孔支架的缺陷,并且采用簡單的熱致相分離法經(jīng)常涉及到有毒溶劑的使用的問題,提出了一種將擠出發(fā)泡法、瀝濾法以及冷凍干燥法相結(jié)合、并通過材料體系和工藝條件的調(diào)控制備獲得了具有雙峰泡孔結(jié)構(gòu)的富含殼聚糖納米纖維的PCL三維多孔支架的新方法,為批量化生產(chǎn)細胞相溶性好、泡孔率高、內(nèi)部連通性好的三維多孔支架提供新思路。
[Abstract]:Biodegradable polymer porous scaffolds is one of the important research direction in the field of tissue engineering, plays a key role in tissue engineering. Synthetic biodegradable polymer has good regulation performance, is widely used in the field of tissue engineering. However, synthetic polymer scaffolds poor hydrophilicity and lack of binding sites for cell adhesion, leading to the growth of cells in the scaffold has been extremely limited. Therefore, how to prepare a good biocompatibility of biodegradable porous scaffolds is a hot and difficult topic in the field of fibrous scaffolds prepared by electrostatic spinning can simulate the biomimetic extracellular matrix is very good, the doctoral dissertation on how to improve the fiber scaffold biocompatibility to do in-depth research and discussion. Firstly, based on the combination of electrospinning, solution blending and freeze drying technology for preparing poly out carbon Acid propylene (PPC) gelatin and natural polymers (gelatin) nano composite fiber scaffolds, thermoplastic polyurethane and graphene oxide (GO) composite fibers of small diameter vascular stent and a PPC micron fiber / chitosan (chitosan) fiber scaffold hierarchy of nano fiber coexist. The study found that when gelatin in the spinning solution content is higher than 10%, gelatin and PPC will cause serious result in separation of spinning liquid splash in the spinning process, fiber bonding and other phenomena. Adding trace acetic acid can improve the compatibility with PPC gelatin, the spinning process of mixture of smooth uniform size of the fiber, and the addition of gelatin greatly to improve the hydrophilicity and cell compatibility of the composite fiber scaffolds; by rotating the type self built collection device were prepared with different GO and PEI contents of TPU/GO, PCL/PEI small diameter stent, on G The structure and morphology of O and PEI on the composite fiber scaffolds, effect of hydrophilic properties, and to human endothelial cells as the cell model, the influence on the growth morphology of GO and PEI content of cells, found the role of low content of GO and PEI on cell growth, and high content of GO and PEI can cause cell death; composition and regulation of solvent to build parallel plate collection device fabricated PPC micron fiber scaffold highly oriented, through the infiltration of chitosan solution and freeze-drying postprocessing, the introduction of chitosan nano fiber in PPC micron fiber stent, stent structure prepared not only has the micron fiber and the nano fiber, and with good biocompatibility of chitosan, cell culture results showed that the micro nano fiber composite structure for cell growth and provide a suitable environment. Secondly, based on electrospinning, using Polycaprolactone (PCL) nanofiber as shish induced polymer molecules in dilute solution on the surface of the wafer to form spontaneous crystallization of periodic arrays of kebab, prepared with micro topology on fiber scaffolds to change the crystal structure of stents, and the use of natural polymer modified shish-kebab fibrous scaffolds to collagen fibers the purpose of the biomimetic extracellular matrix in structure and function. The composition of shish were used to investigate effects of components of kebab solution on the formation of shish kebab structure. The study found: with polycaprolactone (PCL) / nano hydroxyapatite (n HA) on crystal structure of composite fiber as shish prepared has the good performance of the biomimetic mineralization and is beneficial to human osteosarcoma cells (MG63) growth, and the mechanical strength of fiber scaffold is improved; compared with 77% acetic acid and amyl acetate with lower solubility of PCL As the solvent dilute solution is conducive to the formation of regular kebab in PCL nano fiber; using the method of chemical grafting on compatibility matrix with good crystal fiber graft stent surface biological in PCL (Matrigel) can improve the fiber scaffold hydrophilicity and biocompatibility. The solution is found in the research of chemical blending grafting of the shortcomings and deficiencies, this paper presents a new method of chitosan-PCL copolymer in surface crystallization of PCL nanofibers scaffolds, in the crystallization process, the copolymer PCL end will form a periodic arrangement of the wafer in the spinning fiber surface spontaneous crystallization, while the copolymer of chitosan is due to repulsion of PCL fiber was exposed outside. Not only makes the stent has a unique crystal structure on micro topology using the fiber scaffold prepared by the idea of system, and make the composite fibrous scaffold containing chitosan unit to provide fine The cell binding sites. The study found: with good hydrophilicity with stent prepared the design ideas for the mineral properties of bionic, biocompatibility and excellent osteogenic ability. Finally, the defect for regular fiber scaffold prepared by electrospinning the solution is insufficient and difficult to prepared porous support to a specific shape and, by a simple heat often involves the use of toxic solvent induced phase separation problem, puts forward a method of combining extrusion foaming, leaching and freeze drying method, and control system through the material and process conditions were obtained a new method of PCL scaffolds with rich chitosan nanoparticles Shuangfeng fiber foam structure for the mass production of cells, good intermiscibility, bubble rate is high, the internal porous scaffold with good connectivity to provide new ideas.

【學位授予單位】：華南理工大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TQ340.64

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本文編號：1491769