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1.
生物磷灰石是动物和人体骨骼及牙釉质的主要无机矿物成分,磷灰石矿物晶体的组成和结构影响了骨及牙釉质的机械强度和生理功能。羟基磷灰石空间群的确定一直存在争议,其中羟基存在两种不同排列方式,使得其具有六方和单斜两种晶相。另外,磷灰石晶体结构中的类质同象替换,影响了其结构、物理和化学特性。本文综述了计算机模拟方法在原子及分子水平上对磷灰石晶体的空间群确定、磷灰石替代机制、小分子及生物大分子相互作用的研究,对磷灰石晶体化学、界面化学及开发生物材料的深入研究具有一定的科学意义和较强的应用价值。  相似文献   

2.
生物矿物及其矿化过程   总被引:5,自引:0,他引:5  
生物体内有机基质指导矿物晶体的成核、生长和聚集,使得生物矿物具有特定的形貌、取向和组装方式,从而产生特殊的功能.本文从有机基质与矿物的晶格匹配、立体化学互补和空间定位、静电作用和电荷匹配,以及分子间弱相互作用力等方面综述了生物矿化过程中所涉及的机理,并讨论了生物矿物的分布和特性、生物矿化过程中的有机基质、生物矿化的过程和类型.  相似文献   

3.
受生物启发模拟合成生物矿物材料及其机理研究进展   总被引:3,自引:0,他引:3  
自然界中存在大量复杂、高度功能化的生物矿物材料如贝壳、珍珠、牙齿、骨骼等,其中很多是非常普通的无机矿物材料。运用仿生合成的思路来制备形貌可控、结构特殊且具有独特性质的材料一直是交叉学科研究的热点,如何模拟生物矿化方法合成功能化材料,正逐渐引起科学界的关注。碳酸钙等生物矿物材料广泛存在于生物和地质体系中,对生物体的特异功能起着极其重要的作用。本文将重点回顾有关碳酸钙等生物矿物材料的生物模拟合成研究的进展。生物矿物合成的微环境主要包括模板和溶液相。本文即从这两方面着手,评述了近年来利用软、硬模板法模拟合成生物矿物的研究进展。  相似文献   

4.
钙硅生物矿化的结构特征及其矿化机制   总被引:3,自引:0,他引:3  
讨论了生物体系中生物矿化作用的主要原理,阐述了钙,硅化合物被生物体作为生物矿物的原因和生物矿物的形成机制,并着重讨论了钙,硅矿化过程的差异,概括了生物矿物的类型,分析了生物矿物及生物矿化的特征。  相似文献   

5.
杨刚  杨高文  徐桦  侯文华 《化学学报》2004,62(2):153-159
应用带有分子碎片相互作用、分子轨道分析等功能的量子化学程序MOAN及分子动力学模拟软件Materials Studio计算了矿物表面的电子结构及其与巯基类浮选剂的相互作用.确定了矿物相的最可几计算模型,提出了合理的吸附作用模型及浮选剂在矿物表面的吸附排列方式,对其吸附作用机理及吸附剂与矿物表面之间的多种电子转移形式作了合理解释,发现巯基苯并类浮选剂的p-π共轭结构对浮选作用有重要的影响,从理论上确定的矿物表面单位面积内单层饱和吸附分子数与实验值接近.讨论了三种不同共轭效应、诱导效应的官能团取代浮选剂的苯环氢原子,对浮选剂的活性及选择性的影响.本研究将对理解浮选的高捕收性和选择性有着重要的意义,直接指导定向合成新型高效浮选剂,浮选试验结果与理论计算基本一致.  相似文献   

6.
生物矿化(Biomineralization)是生物硬组织(软体动物的外壳,脊椎动物的骨和牙等)形成的重要环节,是生物体调控矿物沉积,并利用矿物增强硬组织机能的重要生物策略。生物矿化所形成的生物矿物具有多级有序的结构、优异的机械性能和重要的生理功能,启发了有机-无机复合生物材料的设计和仿生矿化制备,为体内外硬组织修复提供研究思路和奠定材料基础。本文主要综述了生物矿化的基本原理和主要生物矿物,矿物结晶原理和新认识,与硬组织修复密切相关的胶原矿化机制和最新进展,硬组织材料的多级结构特征,以及仿生矿化在硬组织修复中的前沿进展。  相似文献   

7.
李春  于严淏 《应用化学》2022,39(1):74-85
碳酸钙、磷酸钙为代表的生物矿物广泛分布于自然界中,经过不同的矿化过程,在生物体内呈现出多样的结构、形貌和功能,构成生物体多种组织和器官。在人工材料合成领域,仿生矿化通过调控碳酸钙、磷酸钙等矿物的成核与生长,获得具有复杂高级结构和特殊生物功能的无机或无机/有机复合材料。本文重点介绍仿生矿化机理和应用的最近研究进展,包括仿生矿化结晶理论(经典和非经典成核理论)、结晶过程调控方法(无机离子、有机小分子、生物大分子、有机聚合物)以及在生物工程领域的应用(骨组织工程、牙釉质修复、仿生增强材料等),简要展望仿生矿化未来的研究方向,为先进仿生材料的制备与应用提供参考。  相似文献   

8.
南海东北部沉积类型的分布规律   总被引:1,自引:0,他引:1  
本文以沉积物的粒度类型为基础,结合沉积物的生物、矿物、化学组成的特征,从沉积物的成因观点综合分析,把本区沉积物分为陆源碎屑沉积(含五个沉积物带)、生源-陆源沉积(含三个沉积物带),自生-陆源沉积(含某些自生沉积矿物)和火山-陆源沉积(含某些火山碎屑物)等四种沉积类型,并论述了各类型的特征和相互关系及其空间分布等。  相似文献   

9.
王本  唐睿康 《化学进展》2013,(4):633-641
生物矿化是生物体制造生物矿物的过程。在自然界中,生物矿物是在有机基质控制下可控有序组装而成的,这就决定了它不同于实验室中合成的普通矿物。单细胞矿化以及生理和病理性矿化,对于人们开展硬组织生物学研究以及生物材料设计合成具有很好的借鉴和启发意义。作为骨骼、牙齿的基本构筑单元,以及其良好的生物相容性和优异的骨牙整合性,磷酸钙纳米颗粒在生物矿物的组装方面和生物硬组织修复、组织工程等方面扮演着重要的角色。另外,受单细胞生物矿化启发的细胞(或病毒)壳化,可以赋予细胞(或病毒)更好的抗逆境能力。本文综述了生物矿化,尤其是单细胞矿化和生理、病理性矿化对生物医学的启示。结合近年来国内外相关研究进展,我们从骨、牙组织修复,细胞(病毒)壳化两个方面分别阐述了生物矿化作为无机化学和生物医学的桥梁作用。深入研究生物矿化的机理以及基于生物矿化的材料合成,对于生理性矿化的仿生修复、病理性矿化的预防治疗以及细胞界面工程等方面都具有重要的启发和实践意义。  相似文献   

10.
生物矿化是生命体通过调控无机矿物的成核、取向、生长和组装来制造有机-无机复合材料的过程。借鉴生物矿化的原理,可利用有机基质实现无机材料的可控合成,制备出性能优异的新型复合材料。更有趣的是,将材料和生物体从结构和功能两个层面整合,利用材料-生物之间的协同调控,可构筑出新功能生命体,这也是仿生矿化发展的重要方向。本论文首先介绍生物矿化的基本理论和自然界中的生物矿化现象。随后通过对生物矿物结构和功能的阐述,提出仿生构筑新功能生命体的概念,并系统介绍构筑新型材料-生物体的方法,在此基础上系统总结新功能生命体在环保、能源、医学等领域的应用。最后,针对目前该领域存在的局限和问题展开讨论,对实现智能仿生构筑生命体的研究进行展望。我们认为基于仿生矿化构筑新功能生命体的研究能够推动学科边界不断融合,为材料学、化学生物学、生物无机化学以及医学等领域的发展提供新的方向。  相似文献   

11.
The effects of seven carboxylic acids, i.e., acrylic acid, maleic acid, tartaric acid, malic acid, succinic acid, and citric acid, on CaCO(3) crystallization were studied using the unseeded pH-drift method along with a light-scattering technique. Experiments were started by mixing solutions of CaCl(2) and NaHCO(3) in the presence or absence of additives. The crystallization was studied by recording the decrease in pH resulting from the reaction Ca(2+)+HCO(3)(-)-->CaCO(3)+H(+). A given amount of carboxylic acid was added to the solution of CaCl(2) or NaHCO(3) before mixing the reactants. The pH profiles obtained in the case of the CaCl(2) solution containing an additive were similar to those for the NaHCO(3) solution containing one, and when an additive was added after the onset of crystallization, the growth of CaCO(3) immediately stopped. The light-scattering observations, in all cases, indicated that CaCO(3) nucleation occurred at 10-20 s after mixing of the reactants. The results indicated that the nucleation of CaCO(3) was not influenced by the presence of carboxylic acids, but CaCO(3) crystal growth was reduced by their adsorption to the surface of the CaCO(3) crystals. These phenomena were explained by assuming a stronger affinity of the carboxylic acids for CaCO(3) particles than for the free Ca(2+) ions in solution. The crystallization of CaCO(3) in the presence of additives was divided into three stages: nucleation, growth incubation, and growth periods. Copyright 2001 Academic Press.  相似文献   

12.
An asymmetric triblock copolymer, poly(styrene-b-acrylic acid-b-ethylene glycol) (PS-b-PAA-b-PEG), was synthesized via reversible addition-fragmentation chain transfer controlled radical polymerization. Micelles of PS-b-PAA-b-PEG with PS core, PAA shell, and PEG corona were then prepared in aqueous solutions, followed by extensive characterization based on dynamic light scattering, zeta-potential, and transmission electron microscopy (TEM) measurements. The well-characterized micelles were used to fabricate hollow nanospheres of CaCO(3) as a template. It was elucidated from TEM measurements that the hollow nanospheres have a uniform size with cavity diameters of ca. 20 nm. The X-ray diffraction analysis revealed a high purity and crystallinity of the hollow nanospheres. The hollow CaCO(3) nanospheres thus obtained have been used for the controlled release of an anti-inflammatory drug, naproxen. The significance of this study is that we have overcome a previous difficulty in the synthesis of hollow CaCO(3) nanospheres. After mixing of Ca(2+) and CO(3)(2-) ions, the growth of CaCO(3) is generally quite rapid to induce large crystal, which prevented us from obtaining hollow CaCO(3) nanospheres with controlled structure. However, we could solve this issue by using micelles of PS-b-PAA-b-PEG as a template. The PS core acts as a template that can be removed to form a cavity of hollow CaCO(3) nanospheres, the PAA shell is beneficial for arresting Ca(2+) ions to produce CaCO(3), and the PEG corona stabilizes the CaCO(3)/micelle nanocomposite to prevent secondary aggregate formation.  相似文献   

13.
CaCO3 crystallization on a chitosan membrane was studied using diffusion of (NH4)2CO3 vapors into a CaCl2 solution containing differing added amounts of two polyacrylic acids (PAAs) with molecular weights of ca. 2.0 x 10(3) and ca. 4.5 x 10(4). The coexistence of PAA and the chitosan membranes produced thin CaCO3 island crystals, which developed into a continuous CaCO3 film on the membranes. Continuous CaCO3 films consisting of only aragonite formed on the chitosan membranes at the optimum amount of PAA. When the amount of PAA is not optimum, the polymorph of CaCO3 switches from aragonite to vaterite, and the morphology has a tendency to become an isolated island structure. The formation of the aragonite and vaterite island crystals and the appearance of a range of added PAA suitable for their formation are explained by the action of two parallel phenomena: (a) the high concentration of Ca2+ ions in the chitosan membrane vicinity is achieved by the interaction between the -COO- groups of PAA adsorbed by the -NH3+ groups of the chitosan membrane through an electrostatic force and free Ca2+ ions in the CaCl2 solution, which produces the high supersaturation with CaCO3 in the membrane vicinity during CO2 diffusion; (b) PAA, remaining as mobile carboxylic anions in the CaCO3 solution, inhibits the growth of the CaCO3 island crystals by its adsorption. The CaCO3 supersaturation in the membrane vicinity is controlled by regulating the balance of these phenomena, which leads to the formation of the desired CaCO3 polymorph.  相似文献   

14.
The oscillating stability of coral reef seawater pH has been maintained at around physiological pH values over the past 300 years (Pelejero et al., 2005). The stability mechanism of its pH has been interpreted in terms of the buffering dissolution/formation reaction of CaCO(3) as well as the proton consumption/generation reaction in CaCO(3)-saturated water. Here the pH-dependent solubility product [HCO(3)(-)][Ca(2+)] has been derived on the basis of the actual pH-dependent reactions for the atmospheric CO(2)/CO(2 (aq.))/HCO(3)(-)/CO(3)(2-)/Ca(2+)/CaCO(3) system. Overbasic pH peaks appeared between pH approximately 8 and approximately 9.5 during sodium hydroxide titration, as a result of simultaneous CaCO(3) formation and proton generation. The spontaneous and prompt water pH recovery from the acidic to the physiological range has been confirmed by the observation of acid/base time evolution, because of simultaneous CaCO(3) dissolution and proton consumption. The dissolution/formation of CaCO(3) in water at pH 7.5-9 does not take place without a proton consumption/generation reaction, or a buffering chemical reaction of HCO(3)(-)+Ca(2+)right arrow over left arrowCaCO(3)+H(+). SEM images of the CaCO(3) fragments showed that the acid water ate away at the CaCO(3) formed at physiological pH values. Natural coral reefs can thus recover the physiological pH levels of seawater from the acidic range through partial dissolution of their own skeletons.  相似文献   

15.
Controlling the process of crystal growth is of importance to the biomineralization and materials science. In this work, some novel morphology of calcium carbonate (CaCO3) was precipitated in an ethanol-water binary solvent (EWBS) with a CaCl2/Na2CO3 reaction system. For the solutions of CaCl2/Na2CO3 in EWBS, the alcoholization and hydration of Ca2+ and CO3(2-) were discussed from the radial distribution functions by molecular dynamics simulations, and the number density profiles of water molecules around and approximately 15 A away from CO3(2-) were employed to reveal the distribution of water molecules. It is found that EWBS has a divisive effect on Ca2+ and CO3(2-), and the local inhomogeneity of EWBS would be enhanced by adding some Na2CO3 into it. This inhomogeneity results in an aqueous two-phase system as x E goes up to 0.7. In addition, the novel morphology of CaCO3 under different molar ratios of Ca2+/CO3(2-) and in different mixed solvents were confirmed by XRD and SEM, and the relationships between the morphology of CaCO 3 and the structural properties of mixed solvents were further explored.  相似文献   

16.
SiO_2包覆超细CaCO_3的微晶分析和XPS研究   总被引:5,自引:0,他引:5  
0引 言 超细碳酸钙在橡胶、塑料、造纸、涂料、油墨、医药、化妆品等工业中有广泛应用。碳酸钙粉末表面具有许多水羟基,表面是亲水疏油性的 ,易形成聚集体 ,分散性能差 ,直接应用效果不好。因此,根据其本身的性质及其应用目的,对其进行表面处理,以相应提高其应用性能。碳酸钙的表面处理是通过物理或化学方法将表面处理剂吸附或反应在碳酸钙的表面,形成表面改性层,使其表面活性化,以改善碳酸钙的表面性能。目前碳酸钙的表面改性大多为有机表面改性、偶连剂表面改性、高分子(聚合物)表面改性等 [1],而无机表面改性却很少有报道。我…  相似文献   

17.
Density functional theory (Perdew-Burke-Ernzerhof) based methods have been used to study the structure and hydration environment of the building blocks of CaCO 3 in aqueous solutions of calcium bicarbonate and calcium carbonate. Car-Parrinello molecular dynamics simulations of Ca(2+)/CO3(2-) and Ca (2+)/HCO3(-) in explicit water were performed to investigate the formation of CaCO3 and the hydration shell of the solvated hetero-ion pair. Our simulations show that the formation of the monomer of CaCO3 occurs with an associative mechanism and that the dominant building block of calcium (bi)carbonate in aqueous solution is Ca[eta(1)-(H)CO3](H2O)5, i.e., the preferred hydration number is five, while the (bi)carbonate is coordinated to the calcium in a monodentate mode. This result agrees with static calculations, where a hybrid approach using a combination of explicit solvent molecules and a polarizable continuum model has been applied to compute the solvation free energies of calcium bicarbonate species. Furthermore, the discrete-continuum calculations predict that the Ca(HCO3)2 and Ca(HCO3)3(-) species are stable in an aqueous environment preferentially as Ca(HCO3)2(H2O)4 and Ca(HCO3)3(H2O)2(-), respectively.  相似文献   

18.
阴离子氨基酸表面活性剂调控碳酸钙的仿生合成   总被引:1,自引:0,他引:1  
室温下, 在乙醇或乙醇-水混合体系中, 利用氨基酸表面活性剂N-酰基十二烷基肌氨酸钠(Sar)调控合成碳酸钙, 采用SEM, XRD和FTIR等技术表征了反应产物. 在乙醇体系中, 首先形成多面体形状的文石, 然后逐渐转变为圆球状的无定形碳酸钙. 在乙醇-水混合体系中, 合成了花簇状多级结构碳酸钙晶体. 增加N-酰基十二烷基肌氨酸钠的用量有助于形成球霰石结构, 当n(Ca2+)∶n(Sar)=1∶1 时, 得到的花状碳酸钙为球霰石和方解石的混合物, 当n(Ca2+)∶n(Sar)=1∶2 时, 得到纯净的球霰石, 其形貌为大小较均一的单分散的球, 直径约为7 μm; 另外, 当n(Ca2+)∶n(Sar)=1∶1时, 混合溶剂中水和乙醇的体积比由1.5∶1依次增加为7∶3和3∶1时, 碳酸钙晶体的形貌由花状逐渐向球形过渡, 晶体中球霰石和方解石的含量也随之变化, 其中, 当水和醇的体积比为7∶3时, 产物主要为球霰石型晶体.  相似文献   

19.
Hierarchically structured CaCO(3) films were synthesized at atmospheric conditions (room temperature and 1 atm) without the use of templates or amphiphilic molecules in this process. The resulting CaCO(3) film was formed by self-organization between Ca(OH)(2) and aqueous CO(2). The building blocks of the CaCO(3) film were thought to be CaCO(3) primary nanoparticles that aligned to build higher level structures with greater size, called mesocrystals, depending on the additives. The soluble additives played a key role in the control of the morphology, crystallinity, and polymorphism of the CaCO(3) film, and the effects strongly depended on the type of additive and their concentrations. The additives used in this study decreased the crystallinity of CaCO(3) (calcite) film in the order of glucose > aspartic acid > serine in a manner inversely proportional to the concentration of the additives. In addition, Mg(2+), K(+), and Na(+) ion additives led to the formation of an aragonite phase, the proportion of which increased with the concentration of ions. The threshold concentrations of these ions for the formation of the aragonite phase in CaCO(3) film were found to be in the order of Na(+) > K(+) > Mg(2+).  相似文献   

20.
通过化学分析、SEM显微分析技术结合RosinRamiler概率统计理论从介观层次研究Na5P3O10CaOH2CO2H2O体系纳米CaCO3的合成反应及其成核和生长过程。结果表明Na5P3O10对CaOH2的碳化反应具有抑制作用。随着Na5P3O10的增加体系中CaCO3的成核速率B0逐渐增大。在Na5P3O10=0ppm时CaCO3结晶的生长由长程扩散和凝聚生长控制Na5P3O10=380.4760.9ppm时前期受短程扩散和界面反应控制、后期受长程扩散控制。Na5P3O10的存在抑制了纳米CaCO3的晶体生长。  相似文献   

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