活性离子掺杂调控磷酸钙生物材料的性能及其对骨髓间充质干细胞的介导行为

发布时间：2018-03-19 14:12

  本文选题：磷酸八钙　切入点：离子掺杂　出处：《华南理工大学》2016年博士论文　论文类型：学位论文

【摘要】：作为生物磷灰石矿物的一种前驱相,OCP有良好的骨传导性和生物降解性,可用作骨替代修复材料,具有很好的临床应用价值。OCP具有促进成骨细胞分化、诱导破骨细胞形成以及促进新骨形成的能力,这些都与其特定的物理化学特性密切相关。本课题从骨矿物组成仿生的角度出发,选取OCP作为磷酸钙矿物研究模型,在生物活性矿物离子(Fe~(3+)或Sr~(2+))环境下,通过研究具有不同组成、形貌和结构的OCP的相关物理化学特性对生物蛋白分子交互作用和干细胞响应的影响机理,深入模拟研究掺杂活性Fe或Sr离子的OCP的骨传导性和生物降解性。同时,通过掺杂活性离子的方式提高OCP材料的生物活性,为其在骨修复领域中的应用作铺垫。研究表明,通过尿素水解介导的化学均相沉淀法合成的OCP晶体纯度高,结晶度好,呈典型的板片状结构。当反应温度高于70℃时,尿素水解反应的剧烈程度才足够提供控制体系pH值的动力。反应过程中的温度与pH值是沉淀合成反应的关键参数,可通过控制尿素浓度、反应初始pH值、反应温度和反应时间综合控制。获得高纯OCP产物的较佳条件为:尿素浓度0.5 M,初始pH值5.9,反应温度90oC和反应时间2 h。与其他用此法合成的磷酸钙材料相比,合成的OCP材料具有更好的细胞亲和性和黏附性能,以及较好或相近的细胞增殖活性和成骨分化能力。通过温和的化学均相沉淀法分别将Fe~(3+)和Sr~(2+)成功地引入到OCP的结构中,且均引起相应的晶格膨胀,这源于Ca2+在原位分别被半径更大的Fe(OH)_2+/Fe(OH)2+或Sr~(2+)替代。Fe/Sr掺杂并未明显改变OCP晶体的形貌和结构,但特别地,Fe-OCP晶体表面诱导了纳米磷酸铁盐颗粒的沉积。Fe/Sr掺杂显著改变了OCP材料的表面物理化学特性包括比表面积、表面电负性和粗糙度,具有更好的BSA和LSZ的吸附性能。Fe/Sr掺杂材料均能诱导体外磷灰石形成,且在矿化过程中能持续稳定地分别释放出Fe~(3+)和Sr~(2+)。相比于空白样,Fe/Sr掺杂材料均具有更好的细胞亲和性,能显著上调整合素基因的表达,有利于细胞黏附铺展,明显促进细胞的增殖活性;显著上调干细胞成骨分化相关蛋白和基因的表达;提高胎牛血清总蛋白的吸附量。在作用机理上,Fe/Sr掺杂通过改变材料表面物理化学性质,影响了材料的初始的蛋白交互作用、细胞膜-材料表面电荷识别以及材料拓扑结构的刺激响应;同时,动态释放的活性Fe~(3+)和Sr~(2+)参与了细胞的矿化钙结节过程,促进了细胞的体外钙化行为,而Fe~(3+)/Sr~(2+)也具有刺激细胞响应的积极作用。以上两者协同介导了干细胞的响应。通过掺杂量调控Fe~(3+)/Sr~(2+)的释放动力学,根据Fe/Sr系列掺杂材料的生物相容性,评估Fe~(3+)/Sr~(2+)的安全有效剂量浓度,其中,Fe的掺杂量控制应在15 mol.%以内,过高则有一定的毒副作用,而Sr在低于25 mol.%范围内均有益于干细胞响应。此外,从高温热稳定性和温和溶液环境稳定性的角度,控制Fe/Sr掺杂材料的处理条件,获得各种OCP-HA转化状态的OCP材料。这些不同的转化产物均比相应的对照样具有相对更活跃的表面,因而会积极地刺激干细胞的响应。此外,相对于空白样,Fe-OCP和Sr-OCP分别具有更低和更高的稳定性。稳定性的差异会分别影响相应的离子溶出动力学尤其是早期的溶出行为,较高剂量的Fe~(3+)溶出会有一定的毒副作用,而较为稳定的Sr~(2+)释放则能显著促进干细胞的响应。因而需要从表面物理化学特性和活性离子的角度综合衡量有益于Fe/Sr掺杂OCP材料生物活性的处理方法和条件。通过综合控制OCP-HA转化可得到高生物活性的活性离子掺杂磷酸八钙材料,从而提高了其临床骨再生修复的应用价值。同时,从生物成分仿生的角度,在矿物离子参与的条件下,也能更全面和准确地理解OCP-HA转化机制,及其与OCP基生物材料生物相容性的相关性。
[Abstract]:As a precursor to biological apatite mineral phase, OCP bone conductivity and good biodegradability, can be used as bone repair material, has good clinical application value of.OCP can promote osteoblast differentiation, induce osteoclast formation and promote bone formation ability, these are their specific physical chemistry the characteristics are closely related. This topic from the perspective of bionic bone mineral composition, OCP is selected as a model of calcium phosphate minerals, the biological activity of mineral ions (Fe~ (3+) or Sr~ (2+)) environment, through research with different composition, morphology and structure of OCP related physical and chemical properties of biological effect mechanism protein molecular interaction and stem cell response, bone conduction and biodegradability of deep simulation on the activity of Fe or Sr ion doped OCP. At the same time, improve the biological activity of OCP materials by doping the active ion mode , in order to pave the way for its application in bone repair in the field. The results show that the chemical urea hydrolysis mediated by homogeneous precipitation of OCP crystals synthesized by high purity, good crystallinity, a typical plate-like structure. When the reaction temperature is higher than 70 DEG C, the severe degree of urea hydrolysis reaction is enough to provide control power system pH value. In the process of reaction temperature and pH value are the key parameters of precipitation reaction, by controlling the concentration of urea, the initial pH value, comprehensive control of reaction temperature and reaction time. The optimum conditions to obtain high purity OCP product is urea concentration 0.5 M, initial pH 5.9, reaction 90oC temperature and reaction time of 2 h. compared with other synthetic method of calcium phosphate materials, synthetic OCP material has better cell affinity and adhesion, and cell proliferation activity better or similar and osteogenic differentiation ability. Through chemical and temperature are Precipitation method respectively, Fe~ (3+) and Sr~ (2+) is successfully introduced into the structure of OCP, and cause the corresponding lattice expansion, which originates from the Ca2+ in situ were greater radius of Fe (OH) _2+/Fe (OH) 2+ or Sr~ (2+) morphology and structure instead of.Fe/Sr doping no obvious change of OCP crystal, but in particular, the surface of Fe-OCP crystal induced by nano iron phosphate particles deposition of.Fe/Sr doping significantly changed the surface physical and chemical properties of OCP materials including specific surface area, surface roughness and electronegativity, the adsorption properties of.Fe/Sr doped material has better BSA and LSZ can induce apatite the formation, and in the mineralization process can consistently respectively release Fe~ (3+) and Sr~ (2+). Compared with the blank sample, Fe/Sr doped materials have better cell affinity, can significantly adjust the expression of CYP genes, is conducive to cell adhesion and spreading, significantly promote cell Proliferation; up-regulated expression of stem bone differentiation related gene and protein in cells; improve the adsorption amount of total protein in fetal bovine serum. The mechanism of action, by changing the physical and chemical properties of Fe/Sr doped material surface, the effect of initial protein interaction materials, cell membrane surface charge and material topology recognition at the same time, the activity of stimulus response; dynamic release of Fe~ (3+) and Sr~ (2+) participate in the mineralization of calcium nodule cells, promote cell behavior in vitro calcification, while Fe~ (3+) /Sr~ (2+) also has a positive role to stimulate cell rings. The above two collaborative mediated stem cell response by doping. The regulation of Fe~ (3+) /Sr~ (2+) release kinetics, according to the compatibility of Fe/Sr series doped materials, biological evaluation of Fe~ (3+), /Sr~ (2+) safe and effective dose of concentration, the doping amount of Fe should be controlled within 15 mol.%, high Have certain side effects, while Sr in less than 25 in the range of mol.% are beneficial to stem cell response. In addition, the thermal stability and the stability of mild solution environment angle, processing condition control of Fe/Sr doped materials, to obtain a variety of OCP-HA transformed state OCP materials. These different transformation products all have relatively more active surface than that of the control sample accordingly, thus actively stimulate stem cell response. In addition, compared with the blank sample, Fe-OCP and Sr-OCP respectively with lower and higher stability. The stability of the difference will affect the corresponding ion dissolution kinetics especially the dissolution behavior of the early, the higher dose of Fe~ (3+) dissolution there will be some side effects, and more stable Sr~ (2+) release could significantly promote stem cell response. Therefore need from the surface physical and chemical properties and active ion angle comprehensive measure is beneficial to Fe/Sr The methods and conditions of processing materials doped OCP biological activity. The activity of ion doped phosphate can have high biological activity of eight calcium materials by means of comprehensive control of OCP-HA conversion, so as to improve the application value of the clinical repair of bone regeneration. At the same time, from the view of Bionics in biological components, mineral ions in the conditions, can be more comprehensive and accurate understanding of OCP-HA transformation mechanism and biological OCP based biomaterials correlation.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ132.32;R318.08
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本文编号：1634611