多孔生物陶瓷支架载药控释体系的研究

发布时间：2018-04-24 22:43

本文选题：丹酚酸B + 羟基磷灰石球粒　；参考：《西南交通大学》2012年硕士论文

【摘要】：一直以来,临床上棘手于对由创伤、感染和肿瘤切除后所造成的大节段骨缺损进行修复。自体骨虽因其具有优良的骨传导性、骨诱导性、成骨潜能和无免疫原性而被视为骨移植材料的金标准,但自体骨来源数量有限,且取骨手术存在至少10%的并发症,植入体内后,需要较长时间的爬行替代过程。而异体骨和异种骨具有抗原性,尤其在移植较大骨时,常因剧烈的免疫排斥反应导致移植失败,并且还有病原传播危险。近年来,人们开始用组织工程的原理和技术,将具有成骨潜能的细胞诱导分化、增殖并种植于支架材料上,形成工程化人工骨,促进大节段骨缺损的修复。然而,在体外构建大尺寸组织工程骨会因体外培养的细胞在植入体内后存活率较低、血管化问题和临床时限等问题而受到诸多限制。同时,临床上为更好地促进骨的愈合,还会给患者施以药物治疗。但由于骨组织在生物学上的如密度大、血流量低、渗透性差等特殊性,传统给药方式使药物很难按理想状态到达病变部位,从而疗效低。羟基磷灰石(HA)的组成和结构与自然骨的极为相似,有良好的生物相容性、骨传导性和骨诱导性,被广泛应用为骨的替代材料。HA能吸附化学药物小分子和蛋白质等生物大分子,所以将其作为药物载体被广为研究。但其作为药物载体存在有如表面易吸附杂质、载药率低和突释问题。我课题组前期创新地研究并制备了由多孔生物陶瓷球粒堆积的孔隙100%互通、孔隙大小、孔隙率可控且可与生物活性物质均匀混合的大尺寸(Φ1～1.5×3-4cm)多孔支架,以期修复超临界尺寸的骨缺损。本实验旨在在此支架上,负载可促骨生长、促血管化的生物活性物质,使其成为缓释体系,期在修复骨缺损中持续有效地释放活性物质,促进骨生长及愈合。本实验用溶胶-凝胶法和W/O乳化成球技术制备了HA多孔球形颗粒,并对球粒的孔隙结构进行了表征；考察了丹酚酸B (Sal B)对成骨细胞增殖和分化的影响；将HA球粒作为药物载体,利用其吸附性将Sal B负载其上,同时考察分别用几种不同浓度的PLA和几种不同浓度的壳聚糖对载药球粒进行包裹后药物的释放情况,选择出较佳的包裹物质及其浓度,成功制得壳聚糖包裹的Sal B缓释HA球粒,考察该缓释体系对成骨细胞活性的影响。本实验获得的结论如下： 1.采用溶胶/凝胶法和W/O乳化成球技术制备的HA球粒具有组织生长需要的微观孔结构。 2. Sal B能有效地促进成骨细胞增殖、分化及细胞外基质矿化,提高成骨细胞的总代谢活性和碱性磷酸酶的表达从而促进成骨。当Sal B的质量浓度≤160μg/mL时对成骨细胞的增殖和分化有明显的促进作用,且质量浓度越高效果越明显；但当Sal B的质量浓度高于160μg/mL时,便对成骨细胞产生毒性,导致其凋亡。由此得出,Sal B可作为促骨生长和愈合的生物活性物质应用于骨缺损的修复,且最佳药效浓度为160μg/mL。 3.由于PLA的疏水性,其所形成的膜不能很好的附着在HA球粒表面,易脱落,所以几种不同浓度的PLA对载药球粒的包裹效果都不好。而壳聚糖亲水性和成膜性好,且具有良好的细胞相容性,最终选用2%的壳聚糖溶液包裹制得载Sal B的缓释HA球粒。 4.壳聚糖包裹Sal B缓释HA球粒可在体外长时间内释放具有生物活性的Sal B,维持有效促进成骨细胞增殖的浓度并保持成骨细胞的生物学活性,较长时间内促进成骨细胞分裂和增殖,能满足骨创伤治疗中所需要的持续性促进骨形成的能力,为修复大截段骨缺损提供了新的途径。
[Abstract]:It has been clinically difficult to repair large segmental bone defects caused by trauma, infection and tumor resection. The autogenous bone is considered as the gold standard for bone graft, although it has excellent bone conductivity, bone induction, osteogenic potential and no immunogenicity, but the number of autologous bone sources is limited, and at least 1 of the bone removal surgery exists. 0% of the complications, after implantation, need a long time crawling replacement. Allograft and xenogeneic bone are antigenicity, especially in large bone graft, often caused by severe immune rejection, and the risk of pathogen transmission. In recent years, the principles and techniques of tissue engineering have begun to have osteogenic potential. The cells were induced to differentiate, proliferate and grow on scaffold materials to form engineering artificial bones to promote the repair of large segmental bone defects.
However, the construction of large size tissue engineering bone in vitro will be limited by the low survival rate, vascularization and clinical time limit for the cells cultured in vitro. At the same time, it can improve the healing of bone and give the patient the treatment of drugs. But because the bone tissue is very dense in Biology, Because of low blood flow and poor permeability, the traditional way of administration makes it difficult for the drug to reach the lesion according to the ideal state, so its curative effect is low.
The composition and structure of hydroxyapatite (HA) are very similar to those of natural bone. It has good biocompatibility, bone conductivity and bone inducibility. It is widely used as a substitute material of bone,.HA, to adsorb small molecules and proteins such as chemical drugs and proteins, so it is widely studied as a carrier of drug, but it is used as a drug carrier. It is easy to adsorb impurities such as surface, low drug loading rate and sudden release.
In the earlier period, we studied and prepared a large size (1 to 1.5 x 3-4cm) porous scaffold with porous bioceramic spherules 100% interworking, pore size, controlled porosity and uniform mixing with bioactive substances to repair bone loss in supercritical size. This experiment was designed to promote bone growth on this scaffold. A long, vascularized bioactive substance makes it a slow release system, which can effectively release active substances and promote bone growth and healing in repairing bone defects.
In this experiment, the porous HA particles were prepared by sol-gel method and W/O emulsifying technique, and the pore structure of the pellets was characterized. The effect of salvianolic acid B (Sal B) on the proliferation and differentiation of osteoblasts was investigated. HA pellets were used as drug carriers to load Sal B by their adsorbability, and several different kinds of differences were used respectively. The concentration of PLA and several different concentrations of Chitosan on the drug delivery of drug loaded pellets were released. The better inclusion substance and its concentration were selected. The Sal B sustained-release HA pellets coated with chitosan were successfully prepared, and the effect of the sustained release system on the activity of osteoblasts was investigated. The conclusions are as follows:
1. the HA spherules prepared by sol gel method and W/O emulsification technology have the micro pore structure needed for tissue growth.
2. Sal B can effectively promote osteoblast proliferation, differentiation and extracellular matrix mineralization, increase the total metabolic activity of osteoblasts and the expression of alkaline phosphatase to promote osteogenesis. When the mass concentration of Sal B is less than 160 UX, the proliferation and differentiation of osteoblasts is obviously promoted, and the higher the mass concentration, the more obvious, but when the mass concentration is higher, the effect is more obvious. When the mass concentration of Sal B is higher than 160 u g/mL, it is toxic to osteoblasts and leads to its apoptosis. Thus, Sal B can be used as a bioactive substance for bone growth and healing to repair bone defects, and the optimum concentration is 160 mu g/mL..
3. because of the hydrophobicity of PLA, the membrane formed is not very good attached to the surface of the HA pellet, and it is easy to fall off. So the encapsulation effect of several different concentrations of PLA on the pellets is not good. The hydrophilic and film forming property of chitosan is good, and it has good cellular compatibility. Finally, 2% chitosan solution is used to package the slow release HA ball carrying Sal B. Grain.
4. chitosan encapsulated Sal B sustained-release HA pellets can release bioactive Sal B for a long time in vitro, maintain the concentration of osteoblast proliferation effectively and maintain the biological activity of osteoblasts, promote osteoblast division and proliferation for a long time, and can meet the sustained bone formation ability needed in the treatment of bone trauma. It provides a new way for repairing large segment bone defect.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.08

【参考文献】