本文選題：聚乳酸 + 乙交酯-丙交酯共聚物��； 參考：《北京化工大學(xué)》2010年碩士論文

【摘要】： 生物降解高分子已經(jīng)被廣泛的用于組織工程制備支架材料。為了模仿天然的細(xì)胞外基質(zhì),要求支架具有高的孔隙率,纖維直徑在50-500納米,且具有三維孔間結(jié)構(gòu)。目前制備支架的方法有很多,如靜電紡絲法、自組裝技術(shù)、相分離技術(shù)等,但它們都存在各自的優(yōu)缺點(diǎn),為了彌補(bǔ)這些缺點(diǎn)可以采用多種方法相結(jié)合。相分離法制備纖維結(jié)構(gòu)的過(guò)程為聚合物的溶解-冷凝-溶劑萃取-冷凍干燥,但聚合物能否纖維化的關(guān)鍵是聚合物溶液是否能形成凝膠。 本論文首先采用相分離法和冷凍干燥技術(shù)相結(jié)合的方法制備了結(jié)晶性聚乳酸(PLLA)的納米纖維支架,并研究了冷凝溫度和濃度對(duì)纖維形貌的影響。發(fā)現(xiàn)：冷凝溫度越低越有利于纖維化,但在同一冷凝溫度下,能夠發(fā)生纖維化的聚合物溶液有一個(gè)最佳的濃度范圍。通過(guò)在聚乳酸中復(fù)合碳納米管、石墨片、羥基磷灰石或-磷酸三鈣等粒子,成功地制備了PLLA復(fù)合納米纖維支架。無(wú)機(jī)粒子的復(fù)合改善了單純PLLA纖維支架的力學(xué)性能和生物相容性。 本研究還利用相分離法與致孔劑相結(jié)合的方法,以粒徑為200-400微米的氯化鈉或明膠球?yàn)橹驴讋?制備了孔壁為纖維結(jié)構(gòu)的大孔支架。實(shí)驗(yàn)結(jié)果表明,致孔劑的形態(tài),大小直接影響纖維支架中孔的形貌。本文還采用相分離法,針對(duì)乙交酯-丙交酯共聚物(PLGA)的納米纖維化開展了研究。主要考察了乙醇、丙酮和水三種非溶劑對(duì)PLGA75／5納米纖維化的影響,最終確定以一定比例的THF／H2O混合溶劑為溶劑通過(guò)低溫誘導(dǎo)PLGA溶液凝膠化,然后經(jīng)過(guò)溶劑萃取和冷凍干燥,可獲得PLGA納米纖維化支架。研究結(jié)果表明,采用一定比例的溶劑和非溶劑混合,調(diào)節(jié)PLGA在其中的濁點(diǎn)和凝膠點(diǎn),是使無(wú)定型PLGA通過(guò)相分離法實(shí)現(xiàn)納米纖維化的有效途徑。
[Abstract]:Biodegradable polymers have been widely used in tissue engineering to prepare scaffolds. In order to mimic the natural extracellular matrix, the scaffold must have high porosity, fiber diameter of 50-500 nm, and three-dimensional pore structure. At present, there are many methods for preparing scaffolds, such as electrostatic spinning, self-assembly, phase separation, etc., but they all have their own advantages and disadvantages, in order to remedy these shortcomings, we can use a variety of methods to combine. The process of preparing fiber structure by phase separation is dissolution-condensation solvent extraction-freeze-drying but the key to polymer fibrosis is whether the polymer solution can form gel. In this paper, the crystalline poly (lactic acid) (PLLA) nanofiber scaffolds were prepared by phase separation and freeze-drying techniques, and the effects of condensation temperature and concentration on the morphology of the fibers were studied. It is found that the lower the condensation temperature is, the more favorable the fibrosis is, but at the same condensation temperature, there is an optimum concentration range for the polymer solution which can produce fibrosis. The PLLA composite nanofiber scaffolds were successfully prepared through the preparation of carbon nanotubes, graphite sheets, hydroxyapatite or tricalcium phosphate in poly (lactic acid). The composite of inorganic particles improved the mechanical properties and biocompatibility of pure PLLA fiber scaffolds. In this study, macroporous scaffolds with fiber structure were prepared using sodium chloride or gelatin spheres of 200-400 micron diameter as pore inducers by combining phase separation method with pore-forming agent. The experimental results show that the morphology and size of the pore-forming agent directly affect the morphology of the pores in the fiber scaffold. The nano-fibrosis of glycolide-lactide copolymer (PLGA) was also studied by phase separation method. The effects of three non-solvents, ethanol, acetone and water, on PLGA 75 / 5 nano-fibrosis were investigated. The gelation of PLGA solution was induced by a certain proportion of THF / H _ 2O mixed solvent at low temperature, and then was extracted by solvent and freeze-dried. PLGA nanofibrosis scaffolds can be obtained. The results show that mixing a certain proportion of solvent and non-solvent and adjusting the cloud point and gel point of PLGA is an effective way to realize nano-fibrosis by phase separation of amorphous PLGA.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2010
【分類號(hào)】：R318.08

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 王海;聚乳酸/明膠大孔徑支架的構(gòu)建及其細(xì)胞響應(yīng)[D];大連理工大學(xué);2013年

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本文編號(hào)：2054010