【摘要】：生物礦化材料是指由生命系統(tǒng)參與合成的天然的生物陶瓷和生物高分子復(fù)合材料。生物中有各種各樣的礦化材料,如骨骼、牙齒、珍珠和貝殼等。這種在生命過(guò)程中構(gòu)建的以無(wú)機(jī)物為基礎(chǔ)的結(jié)構(gòu)過(guò)程稱為生物礦化。仿生礦化是模擬生物礦化過(guò)程合成人工晶體的一種方法。生物礦化中的無(wú)機(jī)礦物往往是在有機(jī)基質(zhì)的參與下形成的,它們?cè)谟袡C(jī)基質(zhì)上成核,并且在整個(gè)結(jié)晶過(guò)程中受到了有機(jī)基質(zhì)及其它生命活動(dòng)的調(diào)控,因而在晶體的形態(tài)、尺寸以及取向上都具有高度的統(tǒng)一和有序性。根據(jù)生物礦化中有機(jī)分子調(diào)控?zé)o機(jī)礦物成核生長(zhǎng)的原理,本課題從以下幾個(gè)方面進(jìn)行了研究工作： 本文通過(guò)設(shè)計(jì)發(fā)明一種表面活性劑輔助的化學(xué)共沉淀法,使得羥基磷灰石晶體在表面活性劑分子模板控制下成核并生長(zhǎng),制備出尺寸大小均勻的羥基磷灰石晶粒。首先將摩爾濃度比為5：3的含Ca2+和HPO4-的溶液同時(shí)滴加到表面活性劑濃度為2倍臨界膠束濃度(CMC)的堿性溶液(pH≥12.0)中。當(dāng)Ca2+和HPO4-的溶液滴加完成,使得混合溶液中的表面活性劑濃度正好為1CMC。借助X射線衍射、透射電鏡、傅里葉紅外轉(zhuǎn)換光譜等方法對(duì)樣品進(jìn)行表征,獲得如下實(shí)驗(yàn)結(jié)果：羥基磷灰石晶粒尺寸大致相等,反應(yīng)溫度的提高使得生成的羥基磷灰石的晶型變好,但采用不同的表面活性物質(zhì)作為分子模板使得生成的羥基磷灰石的形貌差別很大。 此外,本文使用明膠作為有機(jī)分子模板,在接近人體生理?xiàng)l件(pH=7.0,37℃)下,成功制備出具有規(guī)則六方棱柱結(jié)構(gòu)的氟磷灰石納米晶體。通過(guò)設(shè)計(jì)對(duì)照組實(shí)驗(yàn)發(fā)現(xiàn),在明膠分子存在的條件下,反應(yīng)時(shí)間的長(zhǎng)短對(duì)晶體形貌產(chǎn)生直接影響；另外,明膠分子的存在還影響了氟磷灰石晶體中的晶格置換。 在上述研究的基礎(chǔ)上,根據(jù)表面活性劑和明膠的物理化學(xué)特性,明膠可被制備成凝膠；而且,氟磷灰石和羥基磷灰石就制備條件相比,前者在溫和條件下即可制備出純度很高的物相。本文通過(guò)將配制好的含有磷酸氫根和氟離子的離子層凝膠以及不含任何離子的屏蔽層凝膠先后鋪在特定基片上,并采用中性氯化鈣溶液浸泡,在基片材料上生長(zhǎng)出一層均勻致密的氟磷灰石涂層。研究表明,涂層的物相成分主要是氟磷灰石,此外還含有少量的明膠或其水解產(chǎn)物。隨著仿生礦化時(shí)間的延長(zhǎng),涂層的厚度不斷增加(生長(zhǎng)速率約為0.8μm/d)。通過(guò)對(duì)不同生長(zhǎng)時(shí)間的涂層進(jìn)行納米壓痕測(cè)試,發(fā)現(xiàn)表面顯微硬度隨著涂層厚度的增加而降低,這主要是殘留在涂層中的少量有機(jī)物質(zhì)造成的。 最后,本文從分子識(shí)別、晶格匹配、靜電作用等方面討論了上述表面活性劑和明膠對(duì)磷灰石晶體生長(zhǎng)的調(diào)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，

本文編號(hào)：2384395