仿生法制备磷灰石及其应用性研究
发布时间：2018-12-17 15:33
【摘要】：生物矿化材料是指由生命系统参与合成的天然的生物陶瓷和生物高分子复合材料。生物中有各种各样的矿化材料,如骨骼、牙齿、珍珠和贝壳等。这种在生命过程中构建的以无机物为基础的结构过程称为生物矿化。仿生矿化是模拟生物矿化过程合成人工晶体的一种方法。生物矿化中的无机矿物往往是在有机基质的参与下形成的,它们在有机基质上成核,并且在整个结晶过程中受到了有机基质及其它生命活动的调控,因而在晶体的形态、尺寸以及取向上都具有高度的统一和有序性。根据生物矿化中有机分子调控无机矿物成核生长的原理,本课题从以下几个方面进行了研究工作： 本文通过设计发明一种表面活性剂辅助的化学共沉淀法,使得羟基磷灰石晶体在表面活性剂分子模板控制下成核并生长,制备出尺寸大小均匀的羟基磷灰石晶粒。首先将摩尔浓度比为5：3的含Ca2+和HPO4-的溶液同时滴加到表面活性剂浓度为2倍临界胶束浓度(CMC)的碱性溶液(pH≥12.0)中。当Ca2+和HPO4-的溶液滴加完成,使得混合溶液中的表面活性剂浓度正好为1CMC。借助X射线衍射、透射电镜、傅里叶红外转换光谱等方法对样品进行表征,获得如下实验结果：羟基磷灰石晶粒尺寸大致相等,反应温度的提高使得生成的羟基磷灰石的晶型变好,但采用不同的表面活性物质作为分子模板使得生成的羟基磷灰石的形貌差别很大。 此外,本文使用明胶作为有机分子模板,在接近人体生理条件(pH=7.0,37℃)下,成功制备出具有规则六方棱柱结构的氟磷灰石纳米晶体。通过设计对照组实验发现,在明胶分子存在的条件下,反应时间的长短对晶体形貌产生直接影响；另外,明胶分子的存在还影响了氟磷灰石晶体中的晶格置换。 在上述研究的基础上,根据表面活性剂和明胶的物理化学特性,明胶可被制备成凝胶；而且,氟磷灰石和羟基磷灰石就制备条件相比,前者在温和条件下即可制备出纯度很高的物相。本文通过将配制好的含有磷酸氢根和氟离子的离子层凝胶以及不含任何离子的屏蔽层凝胶先后铺在特定基片上,并采用中性氯化钙溶液浸泡,在基片材料上生长出一层均匀致密的氟磷灰石涂层。研究表明,涂层的物相成分主要是氟磷灰石,此外还含有少量的明胶或其水解产物。随着仿生矿化时间的延长,涂层的厚度不断增加(生长速率约为0.8μm/d)。通过对不同生长时间的涂层进行纳米压痕测试,发现表面显微硬度随着涂层厚度的增加而降低,这主要是残留在涂层中的少量有机物质造成的。 最后,本文从分子识别、晶格匹配、静电作用等方面讨论了上述表面活性剂和明胶对磷灰石晶体生长的调控作用。
[Abstract]:Biomineralized materials are natural bioceramics and biopolymer composites which are synthesized by life system. There are a variety of mineralized materials in organisms, such as bones, teeth, pearls and shells. This inorganic-based structural process constructed in the course of life is called biomineralization. Biomimetic mineralization is a method to synthesize intraocular crystals by simulating biomineralization process. Inorganic minerals in biomineralization are often formed with the participation of organic substrates, which nucleate on organic substrates and are regulated by organic substrates and other life activities throughout the crystallization process, and thus in crystal form. Both size and orientation have a high degree of unity and order. According to the principle of organic molecules regulating the nucleation and growth of inorganic minerals in biomineralization, the research work is carried out in the following aspects: in this paper, a surfactant assisted chemical coprecipitation method is developed. The hydroxyapatite crystal was nucleated and grown under the control of surfactant molecular template, and the homogeneously sized hydroxyapatite grains were prepared. At first, the solution containing Ca2 and HPO4-, whose molar ratio was 5:3, was dripped into the alkaline solution (pH 鈮，
本文编号：2384395
[Abstract]:Biomineralized materials are natural bioceramics and biopolymer composites which are synthesized by life system. There are a variety of mineralized materials in organisms, such as bones, teeth, pearls and shells. This inorganic-based structural process constructed in the course of life is called biomineralization. Biomimetic mineralization is a method to synthesize intraocular crystals by simulating biomineralization process. Inorganic minerals in biomineralization are often formed with the participation of organic substrates, which nucleate on organic substrates and are regulated by organic substrates and other life activities throughout the crystallization process, and thus in crystal form. Both size and orientation have a high degree of unity and order. According to the principle of organic molecules regulating the nucleation and growth of inorganic minerals in biomineralization, the research work is carried out in the following aspects: in this paper, a surfactant assisted chemical coprecipitation method is developed. The hydroxyapatite crystal was nucleated and grown under the control of surfactant molecular template, and the homogeneously sized hydroxyapatite grains were prepared. At first, the solution containing Ca2 and HPO4-, whose molar ratio was 5:3, was dripped into the alkaline solution (pH 鈮，
本文编号：2384395
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