仿生矿化的机理和应用研究进展

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...     

基于生物矿化的生物壳工程

生物矿化是生物体提高自身存活能力的重要手段,可以通过无机非生命体实现对有机生命体的保护和功能化.得益于这些自然现象的启发,我们将生物矿化原理应用于各种生物单元的功能化改造,进一步提出了仿生壳工程概念.经过生物矿化改造后,生物体系可以维持原有生物性质但又被人工材料赋予了新功能,在材料、生物、医学等各个领域有着重要的价值.本文对基于生物矿化的壳工程修饰方法及其应用进行了介绍,并对该领域的研究前景进行了展望.     

模拟生物矿化过程原位合成活性纳米碳酸钙

生物矿化是一种广泛而复杂的固液之间、有机物和无机物间的物理化学过程．以少量有机质为模板,进行分子操作,高度有序地组合成无机材料．有机基质能作为构造支持的惰性底质或矿物沉淀的局限空间和核化作用的表面,确定矿物质点的形态大小、空间排列、结晶取向和同质多晶类型,并与生物晶体一起确定生物矿物硬体的机械性质．     

生物矿化、仿生合成与形貌调控

介绍了生物矿化材料的种类、结构、特点、形貌调控原则以及基于微生物、蛋白质、多肽、氨基酸和核酸等晶体调节剂的生物矿化材料的合成,总结了近年来生物矿化和彷生合成领域的研究进展.     

仿生矿化与硬组织修复

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。     

仿生矿化增强材料

近年来,随着材料科学领域的发展,机械性能优异且具有特定功能的有机-无机复合材料成为了研究热点。而天然的生物矿化过程产生了在自然界中分布广泛、结构特征多样性、机械性能优异的天然生物矿物,比如牙齿、骨骼、珍珠、贝壳、海胆刺、海洋红虫颚等。这些天然复合增强材料中的矿化组织结构特点和矿化机理为仿生设计与合成具有特定结构、特定功能和优异机械性能的材料提供了理论依据。通过模拟天然过程的仿生矿化方法,利用有机基质调控无机矿物成核生长为固态矿物,最终能够定向组装具有特定有序结构和先进功能的有机-无机复合材料。本文主要综述了自然界中通过生物矿化过程得到的高强度、高韧性的天然复合增强材料,以及受生物矿化增强现象的启发,在化学与材料仿生矿化合成中出现的一些有机-无机复合的增强材料。     

从生物矿化到仿生矿化：构筑新功能生命体

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。     

生物矿化:无机化学和生物医学间的桥梁之一

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。     

生物矿化中的凝聚态化学

不同于研究体相或分子与分子之间的常规化学,凝聚态化学重点关注的是多层次结构的凝聚态物质,主要研究凝聚态物质的化学性质与功能、构筑机制、凝聚态物质之间的反应以及结构与功能间的关系,也是生物矿化研究中特别感兴趣的科学问题。生物矿化是通过有机基质调控无机矿物的生成,构筑具有多层次结构和特殊功能(如保护、传感和运动等)的生物凝聚态物质。研究生物矿化中的化学构筑与结构-功能关系,通过仿生矿化可以设计并制备具有类生物矿物结构和先进功能的仿生凝聚态材料。本文从凝聚态化学的角度介绍生物矿化和仿生矿化领域的概况以及取得的重要成果和新认识,重点综述了本课题组近年来受生物矿化启发,基于无机离子寡聚体的仿生新材料构筑和功能方面的研究成果。相信生物矿化将为新兴凝聚态化学的研究和发展提供良好参考,同时从凝聚态化学的新高度看待和指导生物矿化,也将促进生物矿化研究走向新的台阶。     

无机材料的仿生合成

生物矿化重要的特征之一是细胞分泌的有机基质调制无机矿物的成核和生长, 形成具有特殊组装方式和多级结构特点的生物矿化材料(如骨、牙和贝壳)。仿生合成就是将生物矿化的机理引入无机材料合成, 以有机物的组装体为模板, 去控制无机物的形成,制备具有独特显微结构特点的无机材料, 使材料具有优异的物理和化学性能。仿生合成已成为无机材料化学的研究前沿。本文综述了无机材料仿生合成的发展现状。     

青藏高原湖泊影响锂元素迁移和富集的矿物、元素及环境因素——以西藏郭扎错钻孔沉积物为例

作为我国战略性矿产的锂矿,主要赋存于青藏高原盐湖中。湖泊系统中,锂的富集和迁移规律关系到锂矿的高效提取和未来锂矿的储量估算。本文以西藏咸水湖郭扎错的钻孔沉积物为例,结合AMS14C年代和Mg元素含量变化,系统分析了孔隙水、碳酸盐矿物和硅酸盐矿物的锂含量变化,探讨了矿物、镁元素、环境变化和早期成岩作用等对锂元素迁移和富集的影响。郭扎错沉积物中锂和镁大部分存在于硅酸盐矿物中,锂和镁较高的相关性说明二者存在于相同的硅酸盐矿物中,如粘土矿物。大约90%的锂赋存在硅酸盐矿物中,约8.5%的锂赋存在碳酸盐矿物中,孔隙水中的锂含量占比仅约1.5%。碳酸盐矿物中Mg/Li摩尔比值为78–270,是孔隙水中10多倍,而硅酸盐矿物中的Mg/Li摩尔比值稳定在24–29之间。水–沉积物相互作用促进硅酸盐矿物中锂的释放,咸水环境下释放的锂多于淡水环境下。碳酸盐矿物中,锂和镁主要存在于方解石中。镁离子对锂离子的迁移具有阻碍作用,低温、高盐度下的阻碍作用更强。湖泊沉积物可能是湖水锂的一个重要来源。     

蛭石对高钠高钙准东煤结渣特性影响研究

采用一维沉降炉,辅以灰熔点仪的实验方法,将蛭石与高钠高钙准东煤掺混燃烧,研究其对高钠高钙准东煤结渣特性的影响。结果表明,随着蛭石掺烧量的提高,灰熔点温度呈现先降低后升高的趋势,当掺烧量为6%时灰熔点温度最低;蛭石掺烧量越高,高钠高钙准东煤结渣情况改善越明显,当掺烧量达到4%时,渣样变得疏松多孔,质地变脆,渣样与沉积探针之间的黏附性较弱,极易通过吹灰除去,建议蛭石掺烧量为4%;煤灰中原始矿物质以石英、钙铝黄长石或钙黄长石以及辉石类的低熔点矿物质为主,掺烧蛭石后,含钠的绿辉石矿物质被转化为韭闪石,含铁的斜辉石、赤铁矿等矿物质被转化为铁橄榄石,渣样中的矿物质均以高熔点的镁橄榄石为主;蛭石具有固钠的作用,取样温度越低,蛭石掺混量越高,其固钠效果越明显。     

An online method combining a thermal conversion elemental analyzer with isotope ratio mass spectrometry for the determination of hydrogen isotope composition and water concentration in geological samples

An online continuous-flow method, combining a thermal conversion elemental analyzer (TC/EA) with isotope ratio mass spectrometry (MS), is evaluated for the determination of both the hydrogen isotope composition and the water concentration of hydrous and nominally anhydrous minerals. The technique involves reduction of hydrous minerals or nominally anhydrous minerals by reaction with glassy carbon at 1450 degrees C in a helium stream. The product gases, H2 and CO, are separated on a gas chromatographic column prior to analysis in the mass spectrometer. Calibration curves for the H concentration analysis were generated from a standard of benzoic acid (C7H6O2) that has an H concentration of 5.0 wt%; the analytical uncertainties were better than +/-0.05% in our runs. Two standards of material with given D values, polyethylene IAEA-CH-7 and biotite NBS-30, were tested for the purpose of calibrating a natural garnet 04BXL02 representing nominally anhydrous minerals. Preheating at 90 degrees C for 12 h was found to be suitable for removing adsorption water on the sample surface. This results in constant D values and total H2O contents for the garnet, with weighted means of -94 +/- 1 and 522 +/- 11 ppm (wt), respectively. The TC/EA-MS technique allows routine analysis of sample sizes as small as 0.01 microL H2O. For natural minerals, absolute reproducibilities for D values are +/-0.5 to +/-2 (1) and relative uncertainties for total H2O concentrations are at levels of +/-1% to +/-3% (1). Therefore, this online method can be used for the quantitative determination of H isotope composition and H2O concentration of either hydrous or anhydrous minerals.     

Determination of tungsten in rocks and minerals by chelate extraction and atomic-absorption spectrometry

An atomic-absorption method for determination of tungsten in rocks and minerals is proposed. The method involves sample decomposition by acid digestion or by pyrosulphate fusion, followed by chelate extraction of tungsten by N-benzoylphenylhydroxylamine in toluene. Atomic-absorption measurements are made on the organic phase aspirated into a nitrous oxide-acetylene flame. Quantitative extraction with efficient separation from other elements is achieved in a single extraction from strong acid media. The method is rapid and reliable in terms of precision and accuracy and is applicable to rocks and minerals containing tungsten in the range from 100 ppm to 15%.     

几种非金属矿物对硫化氢吸附性能的研究

某些非金属矿物具有吸附性[1 5]。本文测试了硅藻土、浮岩、沸石和麦饭石等非金属矿物的主要理化性能,研究了上述矿物在不同条件下对硫化氢的吸附性能,探讨了吸附剂粒度、用量、吸附时间和温度对吸附率的影响及吸附机理。在适当的条件下,各种材料对硫化氢的吸附率均能达到90%;吸附能力依次为硅藻土>麦饭石>沸石>浮岩。1　实验部分1 1　材料和试剂采集原矿标本硅藻土(抚松露水河)、浮岩(长白山天池)、麦饭石(长白山遥林)、斜发沸石(长春市净月潭),经粗选、粉碎、制备成不同粒径的吸附剂。X荧光光谱仪(PW140/10型,荷兰)和等离子直读光谱…     

Microanalysis by Laser Ablation-Inductively Coupled Plasma-Atomic Emission Spectrometry in Comparison to Spark Ablation of Certified and Found Minerals Galena, Sphalerite, and Pyrite

A double-tandem technique of inductively coupled plasma-atomic emission spectrometry (ICP-AES) involving laser ablation for the analysis of compact or briquetted minerals on one hand and spark ablation for the analysis of powders on the other is presented. The technical arrangement, the design of the optimized sample chamber, the evaluation of operating conditions, and the test of liquid-solid calibration are described. Both techniques can be used for the determination of elemental compositions of minerals providing a dynamic range from tens of mass-percent down to milligrams per kilogram. The objective of this study was to compare laser ablation (LA)-ICP-AES and spark-ICP-AES with regard to accuracy, precision, and sample turnaround time for multielement analysis of the certified minerals galena GF1, sphalerite SF1, and pyrite PS1. A systematic error of smaller than 3% in both techniques and a random error of smaller than 9 and 5%, respectively, is pointed out. The optimized methods were applied to samples of galena, sphalerite, and pyrite from four deposits each to find fingerprints by different contents of major, minor, and trace elements, which characterize the deposits.     

Effect of treatment with acids on the state of the surface of natural clay minerals

The state of the surface of natural clay minerals containing montmorillonite (lamellar structure), clinoptilolite (rigid skeleton structure), and palygorskite (lamellar-banded structure) and of the same minerals modified with a 17% solution of sulfuric acid was examined. It was established that the modification affected the specific surface area and porosity of the minerals studied. It was found that the degree of increase in the specific surface area after treatment (by a factor of 1.8 for montmorillonite and palygorskite and 1.3 for clinoptilolite) depends on the structure of the mineral and on the content of the mineral-forming component. An increase in the content of montmorillonite in the sample causes an increase in the specific surface area by a factor of 3. The product distribution for the conversion of methylbutynol, a test catalytic reaction, on the surface of the minerals studied shows that it contains both acidic and basic sites.

     

Antimicrobial effects of quaternary phosphonium salt intercalated clay minerals on Escherichia coli and Staphylococci aureus

The aim of this research was to determine the antimicrobial properties and influence factors of four clay minerals intercalated by quaternary phosphonium salt (tetradecyl tributyl phosphonium bromide, TDTB) on antimicrobial effects. Escherichia coli (E. coli) and Staphylococci aureus (S. aureus) were chosen for Minimal Inhibitory Concentration (MIC) tests to evaluate the antimicrobial activities of organ-clay minerals. The properties of organ-clay minerals were analyzed by FTIR, XRD, TEM, Z-Average and Zeta potential, and the releasing amount of TDTB into the broth was measured by ICP. The results showed that montmorillonites-TDTB inhibited the growth of E. coli and S. aureus, and the MICs were 200 ± 20 and 80 ± 15 mg/L, respectively. The amount of TDTB released into the broth was 3.42 ± 0.71%. According to the properties of organ-clay mineral, it was indicated that the antimicrobial activities of organ-clay mineral were the synergic effect of the releasing amount of TDTB, Zeta potential, particle size and distribution. The organ-clay mineral with the larger releasing amount of TDTB, the higher Zeta potential, the same particle size with bacterial size and the narrower size distribution exhibited better antimicrobial activity. The present study demonstrated the properties of organ-clay minerals effected their antimicrobial activities, provided theoretically guidance to promote the antimicrobial activity of clay minerals.     

The effect of mineral fillers on impact and tensile properties of polypropylene

Impact and tensile properties of polypropylene filled with various minerals have been measured. The minerals investigated were dolomite, calcium carbonate, mica and wollastonite. The effect of particle shape, size, content and surface treatment on mechanical properties was studied. A special interest was devoted to the measuring of impact strength, since this is an important property in many applications.

The results show that, for stearic acid treated minerals, there is a marked relationship between decreasing particle size and increasing impact strength. This is especially distinct for the results from the staircase method of ASTM-D3029. Comparing the coarsest and finest fraction of particulate fillers studied, there is a 20-fold difference in impact strength at 50% filler content. The staircase method, compared to the instrumented falling weight impact test, shows a higher sensitivity to changes in impact strength, caused by, for example, variations in particle size or content.     

Dissolution of resistate minerals containing uranium and thorium: Environmental implications

Summary Minerals in the soil range from those that easily weather to those that are very resistant to the weathering processes. The minerals used in this study are referred to as “resistates” because of their resistance to natural weathering processes.¹ It is also known that there are some resistate minerals that have a tendency to contain uranium and thorium within their crystal structure. These resistates can contain as much as 15-20% of the total uranium and thorium present in the soil.⁹ Do resistates dissolve in acids, particularly in the HF/HNO₃ procedures, if not what can be done to the HF/HNO₃ process to dissolve more of the resistate minerals? How would these acid techniques compare to the fusion method used for mineral dissolution? Could the resistate minerals contain considerable amount of uranium and thorium? These were the questions addressed in this research. The comparative data indicate that the use of H₂SO₄ in the dissolution process resulted in ~25% overall increase in the minerals dissolving therefore resulting in a higher yield of extracted uranium and thorium.