双缓释药物支架的制备及其生物学评价

发布时间：2018-01-16 15:31

本文关键词：双缓释药物支架的制备及其生物学评价　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：在骨组织工程中,支架材料扮演着重要的角色,它不仅为细胞的增殖、黏附和细胞外基质的沉积提供生长模板,还可以引导组织的再生和血管化。但是单纯利用生物材料自身组分来调控细胞的行为和促进组织再生,其效果是有限的。目前,将促进骨生长的药物与多孔支架结合是加速骨组织生长的理想方法。但是简单地将支架浸泡在药物中,会导致药物释放过快、释放时间短、局部药物浓度过高等后果,不能有效地加速骨愈合。研究表明将药物缓释体系和支架结合构建药物缓释支架能在局部保持长效而稳定的药物释放,促进成骨细胞的生长,加速骨修复。然而目前的研究主要集中在多孔支架与单一药物缓释体系的结合,在骨修复过程只能提供一种药效,不能满足临床上复杂的要求。因此,多孔支架与多级药物缓释体系提供多种药效协同促进骨组织生长被认为是一个新方向。本文采用模板浸出法制备了具有优良贯通性的羟基磷灰石(HA)支架;分别采用化学交联法和双乳液/溶剂挥发法制备载丹酚酸B(Sal-B)的壳聚糖微球(Sal B-CS微球)和载地塞米松(dex)的聚(乳酸,羟基乙酸)微球(dex-PLGA微球)。通过静电相互作用将Sal B-CS和dex-PLGA微球依次固定在预先涂覆海藻酸盐的多孔HA支架上,干燥后获得双缓释药物支架(al-HAs/Sal B-CS/dex-PLGA支架)。本文研究了 al-HAs/SalB-CS/dex-PLGA支架的机械性能和对细胞生长的影响,主要结果如下:(1)Sal B-CS和dex-PLGA微球均为球形,且具有光滑的表面。Sal B-CS和dex-PLGA微球的平均粒径分别为27μm、7μm。(2)Sal B-CS和dex-PLGA微球成功地固定在表面涂覆海藻酸钠的多孔HA支架上,且载Sal B-CS微球均匀并稳定地分布在支架表面,dex-PLGA微球围绕在Sal B-CS微球周围。(3)制备长径比为3:2的长支架用于力学实验,测定几组不同支架的抗压强度和孔隙率结果发现:随着海藻酸盐进入支架表面微孔,HA支架的抗压强度从1.06 MPa增强至1.55 MPa。此外,随着微球与HA支架的结合,支架的孔隙率降低,但都高于70%,满足临床上对于骨修复支架的要求。(4)体外动力学实验结果表明:与Sal B-CS和dex-PLGA微球相比,al-HAs/SalB-CS/dex-PLGA支架的初期药物突释量较低。在30天内,al-HAs/Sal B-CS/dex-PLGA支架培养液的pH值基本保持7.4不变。(5)用支架浸提液培养成骨细胞,结果表明几组支架均无细胞毒性,具有良好的生物相容性。在几种多孔支架表面培养成骨细胞发现大量成骨细胞粘附在支架表面。成骨细胞增殖实验显示:al-HAs/Sal B-CS/dex-PLGA支架比HA裸支架更利于成骨细胞的生长。炎性因子表达实验表明,双缓释药物支架下调IL-6的表达量;ALP表达实验显示,al-HAs/Sal B-CS/dex-PLGA支架能够促进BMSCs向成骨细胞分化。
[Abstract]:Scaffolds play an important role in bone tissue engineering. They not only provide growth templates for cell proliferation, adhesion and deposition of extracellular matrix. It can also lead to tissue regeneration and vascularization. However, the effects of regulating cell behavior and promoting tissue regeneration by using biomaterial components alone are limited. The combination of bone growth-promoting drugs with porous scaffolds is an ideal way to accelerate bone tissue growth. But simply immersing the scaffolds in drugs can lead to drug release too fast and the release time is short. Local drug concentration too high can not effectively accelerate bone healing. Studies have shown that the combination of drug delivery system and stent can maintain long-term and stable drug release. Promote the growth of osteoblasts, accelerate bone repair. However, the current research focuses on the combination of porous scaffolds with a single drug delivery system, which can only provide one drug effect in the bone repair process. Can't meet complex clinical requirements. It is considered a new direction that porous scaffolds and multistage drug delivery systems provide synergistic effects to promote bone tissue growth. In this paper, hydroxyapatite (HA) scaffolds with excellent transfixibility were prepared by template leaching. Poly (lactic acid) was prepared by chemical crosslinking method and double emulsion / solvent volatilization method for preparation of chitosan microspheres carrying Salvianolic acid (Bal Sal-B) and dexamethasone (dexamethasone). Sal B-CS and dex-PLGA microspheres were sequentially immobilized on porous HA scaffolds coated with alginate by electrostatic interaction. Double sustained-release drug stents were obtained after drying. (alHAs-Sal B-CS-dex-PLGA stents). The mechanical properties of al-HAs/SalB-CS/dex-PLGA scaffold and its effect on cell growth were studied. The main results are as follows: Sal B-CS and dex-PLGA microspheres are spherical. The average particle size of Sal B-CS and dex-PLGA microspheres with smooth surface is 27 渭 m, respectively. Sal B-CS and dex-PLGA microspheres were successfully immobilized on porous HA scaffolds coated with sodium alginate. The Sal B-CS microspheres are uniformly and stably distributed on the surface of the scaffold. Dex-PLGA microspheres were surrounded by Sal B-CS microspheres. (3: 2) long scaffolds with aspect ratio of 3: 2 were prepared for mechanical experiments. The results showed that the compressive strength of HA scaffold increased from 1.06 MPa to 1.55 MPA with alginate entering the surface of the scaffold. With the combination of microspheres and HA scaffolds, the porosity of the scaffolds decreased, but were higher than 70%. To meet the clinical requirements for bone repair scaffolds. 4) the results of in vitro kinetic experiments showed that: compared with Sal B-CS and dex-PLGA microspheres. The initial drug release of al-HAs/SalB-CS/dex-PLGA stent was relatively low and within 30 days. The pH value of al-HAs/Sal B-CSR / dex-PLGA scaffold culture medium remained basically unchanged at 7.4.) Osteoblasts were cultured with scaffold extract. The results showed that the scaffolds had no cytotoxicity. Osteoblasts cultured on several porous scaffolds were found to adhere to the scaffold surface. B-CSR dex-PLGA scaffolds were more conducive to osteoblast growth than HA bare scaffolds. The expression of IL-6 was down-regulated by double sustained-release drug stents. ALP expression assay showed that Sal B-CSP-PLGA scaffold could promote the differentiation of BMSCs into osteoblasts.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318.08

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