载药聚乳酸—羟基乙酸共聚物纤维增韧磷酸钙骨水泥研究

发布时间：2018-06-17 12:17

本文选题：磷酸钙骨水泥 + 电纺纤维　；参考：《西南交通大学》2014年硕士论文

【摘要】：磷酸钙骨水泥(Calcium Phosphate Cements, CPC)因具有良好的生物相容性、骨传导性和可注射性,已作为骨替代材料应用于临床,此外其制备过程中避免了高温烧结工艺,适合作药物和生物活性因子等的载体。但由于CPC易脆、强度低和降解速率慢,只能用在非承重部位且不利于骨组织的生长。纤维常通过桥联、拉拔、负荷传递等作用增强无机材料的力学性能。电纺纤维制备方法简单经济,且与细胞外基质的形态结构相似,已被广泛应用于组织工程。因此,本论文的目的是利用载阿仑膦酸钠(ALN)电纺聚乳酸-羟基乙酸共聚物(PLGA)纤维增韧CPC,同时实现ALN的局部控释。此外ALN还作为改善PLGA纤维在CPC中润湿性的“表面活性剂”。载ALN的PLGA纤维植入机体后可降解形成孔隙,促进新骨的生长,从而更好的满足其临床需求。采用静电纺丝技术分别制备PLGA纤维和载药PLGA纤维。通过扫描电镜(SEM)、酶标仪和接触角测试仪等测定纤维的形貌、尺寸、载药率及接触角等。选用Biocement D磷酸钙骨水泥配方,以磷酸盐缓冲液为液相,液固比为0.45mL/g,将PLGA纤维与CPC混合制备含不同百分含量PLGA纤维CPC,并通过X射线衍射(XRD)、Gillmore双针法、力学性能测试以及SEM检测含PLGA纤维CPC的相成分、凝固时间、力学性能和表面形貌等。采用正交实验优化及分析定向和非定向PLGA纤维、非载药和载药PLGA纤维及PLGA纤维含量对CPC力学性能的影响,并研究最优组表面形貌、凝固时间、相成分、体外降解及药物释放动力学等。此外,采用与成骨细胞(MC3T3-E1)共培养研究各组CPC上细胞黏附、增殖及分化的能力。 PLGA形貌分析表明：纤维表面光滑、分布均匀、持续且纤维彼此分离,空白PLGA纤维和载药PLGA纤维的平均直径分别为1.25±0.18μm和1.16±0.2μmALN的加入并未改变纤维的形貌及尺寸,但减少了纤维的疏水性,接触角由116.8±2.3°降低到94.1±2.5°,药物的包封率可达到56.20±0.99%。含PLGA纤维CPC力学性能测试表明：PLGA纤维的加入可提高CPC弯曲强度、弹性模量,并能显著性提高其韧性,且随着PLGA纤维含量的增加其韧性不断显著提高。正交实验表明最优组合为7wt.%非定向载药PLGA纤维CPC。ALN可改善PLGA纤维在CPC中的润湿性,从而改善PLGA纤维与CPC结合,进一步显著性提高CPC的韧性。材料断口形貌及材料的载荷位移曲线分析表明载药PLGA纤维的加入明显改变了CPC的断裂方式,由脆性断裂变为准脆性断裂。CPC由脆性材料变为准脆性材料。Gillmore双针法测试和相成分结果显示：与空白CPC相比,非载药PLGA纤维和载药PLGA纤维均降低了CPC的初凝和终凝时间。物相分析结果表明加入非载药PLGA纤维或载药PLGA纤维到CPC中,阻碍a-TCP和DCPD的转化,但CPC水化终产物主要为a-TCP和HA以及少量的DCPD和CaCO3。含载药PLGA纤维CPC的药物释放动力学显示第1天的药物释放较快(释放量达10%),而随后药物释放较缓慢,因此可大致分为突释和缓释两个阶段。药物释放动力学符合Higuchi扩散释放模型,持续释放90天药物累积释放量约为89%。XRD检测结果显示,释放90天后CPC中的物相主要为HA；红外分析及SEM检测证明载药PLGA纤维完全降解,且降解后在CPC中留下孔隙。各组CPC与成骨细胞共培养后,活细胞荧光染色和SEM结果表明：各组CPC样品表面都黏附大量的成骨细胞,成骨细胞主要呈多边形,具有强烈的立体感并形成大量的细胞连接。细胞周围伸展出大量伪足,通过伪足与样品表面紧密黏附,呈现良好的细胞活性。Almar Blue和碱性磷酸酶(ALP)检测分析结果表明：各组CPC均呈现有较好的成骨细胞增殖及分化能力,尤其是载药PLGA纤维CPC,释放出促进骨组织生长药物ALN,呈现更好的细胞分化能力。本研究制备了含载药PLGA纤维CPC,载药PLGA纤维能显著提高CPC韧性,同时可实现药物的长时间可持续局部控释,促进骨组织生长。因此载药PLGA纤维CPC适合作为骨填充材料。
[Abstract]:Calcium Phosphate Cements (CPC), because of its good biocompatibility, bone conductivity and injectable, has been used as a bone substitute for clinical application. In addition, it avoids the high temperature sintering process and is suitable for the carrier of drugs and bioactive factors. But because CPC is brittle, low in strength and slow in degradation rate. It can only be used in non load-bearing parts and is not conducive to the growth of bone tissue. The mechanical properties of inorganic materials are enhanced by the effects of bridging, drawing and load transfer. The preparation of electrospun fibers is simple and economical, and is similar to the morphological structure of the extracellular matrix. Sodium lendronate (ALN) toughened CPC by electrospun poly (lactic acid hydroxy acetic acid) copolymer (PLGA) fiber and locally controlled release of ALN. In addition, ALN is also used as a "surfactant" to improve the wettability of PLGA fibers in CPC. The ALN's PLGA fibers can be degraded to form pores and promote the growth of new bone, so as to better meet their clinical needs.
PLGA fibers and drug loaded PLGA fibers were prepared by electrostatic spinning technology. The morphology, size, drug loading rate and contact angle of the fibers were measured by scanning electron microscopy (SEM), enzyme labeling instrument and contact angle tester. The formula of Biocement D calcium phosphate cement was selected, the phosphate buffer solution was liquid phase and the liquid to solid ratio was 0.45mL/g, and the PLGA fiber was mixed with CPC. PLGA fiber CPC with different percentage content was prepared by X ray diffraction (XRD), Gillmore double needle method, mechanical properties test and SEM detection of phase composition of PLGA fiber CPC, solidification time, mechanical properties and surface morphology. Orthogonal experiment was used to optimize and analyze directional and non directional PLGA fiber, non carrier and drug carrying PLGA fiber and PLGA fiber content. The effects on the mechanical properties of CPC were studied, and the surface morphology, solidification time, phase composition, in vitro degradation and drug release kinetics were studied. In addition, the ability of cell adhesion, proliferation and differentiation on CPC was studied by co culture with osteoblast (MC3T3-E1).
The PLGA morphology analysis shows that the fiber surface is smooth, the distribution is uniform, and the fiber is separated from each other. The average diameter of the blank PLGA fiber and the drug loaded PLGA fiber is 1.25 + 0.18 mu m and 1.16 + 0.2 mu mALN, respectively, but the fiber's water thinability is reduced, the contact angle is reduced from 116.8 + 2.3 to 94.1 + 2.5 degrees. The encapsulation efficiency of the drug can reach 56.20 + 0.99%.
The mechanical properties test of CPC containing PLGA fiber shows that the addition of PLGA fiber can improve the flexural strength, modulus of elasticity of CPC, and improve its toughness remarkably, and with the increase of PLGA fiber content, the toughness is continuously improved. The orthogonal experiment shows that the optimal combination of 7wt.% non directional carrier PLGA fiber CPC.ALN can improve the performance of PLGA fiber in CPC. Wettability, thus improving the combination of PLGA fiber and CPC, and further significantly improving the toughness of CPC. Analysis of fracture morphology and load and displacement curves of material shows that the addition of drug PLGA fiber obviously changes the fracture mode of CPC, from brittle fracture to quasi brittle fracture.CPC from brittle material to quasi brittle material.Gillmore double needle method test. The results of the phase composition show that compared with the blank CPC, the non loaded PLGA fibers and the drug loaded PLGA fibers both reduce the initial and final setting time of the CPC. The results of phase analysis show that the addition of non loaded PLGA fiber or PLGA fiber to CPC prevents the conversion of a-TCP and DCPD, but CPC hydration end products are mainly a-TCP and HA, and a small amount of CPC.
The drug release kinetics of the drug loaded PLGA fiber CPC showed that the release of the drug was faster in first days (10%), and the subsequent release of the drug was slow, so it could be roughly divided into two stages of sudden release and sustained release. The drug release kinetics accorded with the Higuchi diffusion release model, and the cumulative release of the drug for 90 days was about the result of the detection of the drug. 90 days after release, the phase of CPC was mainly HA; infrared analysis and SEM test showed that the drug PLGA fiber was completely degraded, and the pores were left in CPC after degradation. After co culture of CPC and osteoblasts in each group, the fluorescent staining of living cells and the results of SEM showed that the surface of CPC samples adhered to a large number of osteoblasts, and the osteoblasts were mainly multilateralism It has a strong sense of stereoscopic and a large number of cell connections. A large number of pseudo feet are extended around the cells, and the cells are closely adhered to the surface of the sample by the pseudo foot. The results show that the good cell activity.Almar Blue and alkaline phosphatase (ALP) detection and analysis show that all groups of CPC have a better ability of osteoblast proliferation and differentiation, especially the load. The drug PLGA fiber CPC released ALN, which promoted bone tissue growth, and showed better cell differentiation ability.
In this study, the drug loaded PLGA fiber CPC was prepared, and the drug loaded PLGA fiber could significantly improve the toughness of the CPC. At the same time, the long-term local controlled release of the drug could be realized and the growth of bone tissue was promoted. Therefore, the drug loaded PLGA fiber CPC was suitable as a bone filling material.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R318.08

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