DOCSLIB.ORG

Synthetic Seashells: Biomimetic Mineral Nucleation at a Langmuir Monolayer E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Synthetic Seashells: Biomimetic Mineral Nucleation at a Langmuir Monolayer E Synthetic Seashells: Biomimetic Mineral Nucleation at a Langmuir Monolayer E. DiMasi1, V.M. Patel2, S. Munisamy2, M. Olszta2, and L.B. Gower2 1Brookhaven National Laboratory 2University of Florida Biogenic minerals, formed by living organisms, registry between the template and the final crystal is have properties quite different from those of their inor- called into question – the template may still influence ganic counterparts. Mollusk shells are exemplary crystallization, but the mechanisms for crystallization biominerals. They are laminates, composed of calcium from a dilute solution are likely to be quite different from carbonate, layered with an organic matrix. These ma- those of crystallization from a dense viscous or solid terials are structured in a hierarchical manner, in which phase. Neither optical microscopy nor electron diffrac- micron-scale mineral crystallites of controlled shape and tion can provide the necessary structural information orientation are arranged into the larger pattern. Ther- to clarify this problem. modynamically stable and unstable mineral forms can In-situ synchrotron x-ray scattering studies can fill coexist within the same organism, such as for the red this gap and shed new light on the mechanisms of abalone (Haliotis rufescens) where the exterior of the biomineralization. In this article we describe recent ex- shell is calcite, but the nacre (mother-of-pearl) layer is periments on biomimetic calcium carbonate nucleation. composed of crystals of aragonite, a less stable poly- Our model system consists of a liquid subphase and a morph of calcium carbonate. Nacre is twenty times surfactant monolayer, and provides several advantages. stronger, in terms of both fracture toughness and spe- First, the monolayer template’s surface charge and lat- cific flexural strength, than inorganic calcium carbon- tice spacing may be tuned through careful choice of ate, due to its laminated structure [1]. Such structural the organic surfactant, and by the application of sur- organization on nanometer to micron length scales in face pressure [4]. Similarly, the ingredients of the synthetic materials would be highly desirable, but this subphase can be controlled, and may include the nucle- goal has not yet been achieved. ating species along with additional metals or organic What will it take to “grow” biomimetic (that is, syn- molecules thought to influence crystallization. Most thetic but bio-inspired) composites? It is clear that the importantly, in-situ x-ray scattering allows us to deter- routes to biomineralization are very diverse. For ex- mine the structure of the mineral from its inception as a ample, certain crustaceans, sponges, and other organ- collection of calcium ions at a monolayer interface, to isms produce amorphous CaCO3 [2]; abalone shell is various bulk phases including macroscopic crystals as microcrystalline; and sea urchin spines are millimeter- well as amorphous thin films. We make use of two long “single crystals” with exceptional alignment across complementary techniques. X-ray reflectivity is a sen- domain boundaries [3]. The complex morphology of sitive probe of the density profile along the surface nor- biogenic minerals is controlled by two important aspects mal direction. It is essentially a measurement of inter- of their environment during mineralization: the soluble ference between x-rays reflecting from boundaries par- chemical species present, which affect the rate of crystal allel to the surface: in our case, the air-monolayer and nucleation and growth, and can also stabilize different monolayer-mineral or monolayer-water interfaces are crystal faces; and an organic insoluble substrate, which identified and the density of each region can be mod- can provide a template for controlled nucleation of spe- eled and fit to the data [5]. In-plane diffraction mea- cific crystallographic phase or orientation, and acts as surements are also conducted, with the x-ray beam at a boundary surface for controlling crystal size and grazing incidence to the surface, so that the near-sur- shape. The relative importance of the template versus face region rather than the bulk is probed. This way, the kinetics is not understood in a general way for the surfactant molecule spacing in the plane as well as biomineralizing systems. One reason for this is that up the crystallinity of the underlying mineral can be deter- to now, no in-situ probes on atomic length scales have mined. The present work was performed using the been available. This means that even when an organic Harvard-BNL liquid surface spectrometer at NSLS material forming the boundary surface of the biomineral beamline X22B. appears to have a good registry with the atomic posi- Our experimental conditions are illustrated in the tions of the crystal faces, it has been very difficult to top panel of Figure 1. In all cases, the surfactant is confirm that the mineral is in fact crystalline at early arachidic acid (CH3[CH2]18COOH): when spread from growth times. If mineralization proceeds first via an chloroform solution onto an aqueous subphase and amorphous precursor phase, the significance of atomic compressed in a Langmuir trough, the molecules stand NSLS Activity Report 2001 2 - 138 up to form a monolayer at the air-water inter- face. In Scheme (a), the subphase consists of a diluted calcium bicarbonate solution which is acquired by bubbling CO2 through a suspension of calcite crystals [6]. The deprotonated -COOH headgroups are ex- pected to attract a layer of calcium ions (shown as red balls) at the surface. As CO2 gas escapes from the liquid, the calcium carbonate supersaturation is raised and mineralization proceeds. This system was previously shown to favor the nucleation of oriented vaterite crystals at the surface, as opposed to the calcite that forms in the ab- sence of a monolayer [7]. Schemes (b) and (c) incorporate acidic macromolecules and metal ions, as found in biological environ- ments. In scheme (b), poly(acrylic acid) is added to the supersaturated calcium bicar- bonate solution. CO2 gas escape drives mineralization just as in scheme (a). The polymer (shown as scribbles in the figure) retards calcite crystallization and forces mineralization to proceed via a hydrated amorphous phase [8]. In scheme (c), car- bonate supersaturation is controlled in a 2- different way: here, CO3 species are sup- plied by pumping an ammonium carbonate solution into a solution containing Ca2+, along with Mg2+ and poly(aspartic acid) as inhibitors. Under some conditions this recipe forces mineralization through a novel liquid precursor phase discovered very re- cently [9]. This polymer-induced liquid-pre- cursor (PILP) process was previously found to form macroscopic amorphous films at stearic acid monolayers on water, and sub- sequently to crystallize into calcite. An opti- cal micrograph through crossed polarizers, showing a spongy amorphous film along Figure 1. Top: recipes for mineralization, beginning with a surfactant with precursor droplets, is shown in Figure monolayer (arachidic acid, CH3[CH2]18COOH) on an aqueous 2. When the precursor is in the liquid form, subphase. (a) Supersaturated calcium bicarbonate solution diluted it can flow into cavities of arbitrary shape, 1:1 with water to produce an undersaturated solution. Carbon diox- and upon solidification, the crystalline cal- ide gas escape raises calcium carbonate saturation and promotes cite then retains the morphology of the mineralization. (b) Supersaturated calcium bicarbonate subphase with molding space. This process suggests a polyacrylic acid. (c) Calcium and magnesium cations in solution, car- bonate solution pumped into subphase. Bottom: possible outcomes simple mechanism for “molding” crystalline for mineralization. (d) Crystallization controlled directly by atomic biogenic minerals to obtain the curved registry with monolayer template. (e) Amorphous mineral precursor, shapes so often observed in nature, and collected at charged boundary surface. (f) Mineral precursor nucle- for this reason, understanding the liquid ates without interacting with monolayer. Red balls, green balls, bent precursor phase is of special interest. Min- molecules, triangular molecules, and black scribbles represent Ca eralization therefore proceeds through di- cations, Mg cations, water molecules, carbonate groups, and soluble verse routes, which we summarize sche- polymers respectively. matically in the bottom panel of Figure 1. Figure 1(d) shows the template-driven ex- 2 - 139 Science Highlights treme proposed in the literature, where crystal faces region, shown by the corresponding model in Figure align directly at the monolayer template. Figure 1(e) 4(b). This may be explained by Ca2+ ions collecting at describes an amorphous mineral layer (whether liquid the charged headgroups. After a twelve hour interval, or solid), that simply collects at the charged boundary the reflectivity is essentially the same, except for being surface and may subsequently crystallize. We must also much lower near q=0. This is simply due to homoge- be prepared for the situation depicted in Figure 1(f), in neous nucleation of macroscopic calcite crystals from which the mineral phase ignores the “template” and solution, which clutter the surface and interrupt the nucleates on its own. beam at low incident angles. Grazing incidence diffrac- X-ray reflectivity is the most effective way of distin- tion in this case was consistent with hexagonally guishing the structures described above. A reflectivity packed, untilted
Load more

Recommended publications
  • Four Hundred Million Years of Silica Biomineralization in Land Plants
    Four hundred million years of silica biomineralization in land plants Elizabeth Trembath-Reicherta,1, Jonathan Paul Wilsonb, Shawn E. McGlynna,c, and Woodward W. Fischera aDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125; bDepartment of Biology, Haverford College, Haverford, PA 19041; and cGraduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan Edited by Thure E. Cerling, University of Utah, Salt Lake City, UT, and approved February 20, 2015 (received for review January 7, 2015) Biomineralization plays a fundamental role in the global silicon Silica is widely used within plants for structural support and cycle. Grasses are known to mobilize significant quantities of Si in pathogen defense (19–21), but it remains a poorly understood the form of silica biominerals and dominate the terrestrial realm aspect of plant biology. Recent work on the angiosperm Oryza today, but they have relatively recent origins and only rose to sativa demonstrated that silica accumulation is facilitated by taxonomic and ecological prominence within the Cenozoic Era. transmembrane proteins expressed in root cells (21–24). Phy- This raises questions regarding when and how the biological silica logenetic analysis revealed that these silicon transport proteins cycle evolved. To address these questions, we examined silica were derived from a diverse family of modified aquaporins that abundances of extant members of early-diverging land plant include arsenite and glycerol transporters (19, 21, 25, 26). A clades, which show that silica biomineralization is widespread different member of this aquaporin family was recently identi- across terrestrial plant linages. Particularly high silica abundances fied that enables silica uptake in the horsetail Equisetum,an are observed in lycophytes and early-diverging ferns.
    [Show full text]
  • Biomineralization and Global Biogeochemical Cycles Philippe Van Cappellen Faculty of Geosciences, Utrecht University P.O
    1122 Biomineralization and Global Biogeochemical Cycles Philippe Van Cappellen Faculty of Geosciences, Utrecht University P.O. Box 80021 3508 TA Utrecht, The Netherlands INTRODUCTION Biological activity is a dominant force shaping the chemical structure and evolution of the earth surface environment. The presence of an oxygenated atmosphere- hydrosphere surrounding an otherwise highly reducing solid earth is the most striking consequence of the rise of life on earth. Biological evolution and the functioning of ecosystems, in turn, are to a large degree conditioned by geophysical and geological processes. Understanding the interactions between organisms and their abiotic environment, and the resulting coupled evolution of the biosphere and geosphere is a central theme of research in biogeology. Biogeochemists contribute to this understanding by studying the transformations and transport of chemical substrates and products of biological activity in the environment. Biogeochemical cycles provide a general framework in which geochemists organize their knowledge and interpret their data. The cycle of a given element or substance maps out the rates of transformation in, and transport fluxes between, adjoining environmental reservoirs. The temporal and spatial scales of interest dictate the selection of reservoirs and processes included in the cycle. Typically, the need for a detailed representation of biological process rates and ecosystem structure decreases as the spatial and temporal time scales considered increase. Much progress has been made in the development of global-scale models of biogeochemical cycles. Although these models are based on fairly simple representations of the biosphere and hydrosphere, they account for the large-scale changes in the composition, redox state and biological productivity of the earth surface environment that have occurred over geological time.
    [Show full text]
  • A Perspective on Underlying Crystal Growth Mechanisms in Biomineralization: Solution Mediated Growth Versus Nanosphere Particle Accretion
    CrystEngComm A perspective on underlying crystal growth mechanisms in biomineralization: solution mediated growth versus nanosphere particle accretion Journal: CrystEngComm Manuscript ID: CE-HIG-07-2014-001474.R1 Article Type: Highlight Date Submitted by the Author: 01-Dec-2014 Complete List of Authors: Gal, Assaf; Weizmann Institute of Science, Structural Biology Weiner, Steve; Weizmann Institute of Science, Structural Biology Addadi, Lia; Weizmann Institute of Science, Structural Biology Page 1 of 23 CrystEngComm A perspective on underlying crystal growth mechanisms in biomineralization: solution mediated growth versus nanosphere particle accretion Assaf Gal, Steve Weiner, and Lia Addadi Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel 76100 Abstract Many organisms form crystals from transient amorphous precursor phases. In the cases where the precursor phases were imaged, they consist of nanosphere particles. Interestingly, some mature biogenic crystals also have nanosphere particle morphology, but some are characterized by crystallographic faces that are smooth at the nanometer level. There are also biogenic crystals that have both crystallographic faces and nanosphere particle morphology. This highlight presents a working hypothesis, stating that some biomineralization processes involve growth by nanosphere particle accretion, where amorphous nanoparticles are incorporated as such into growing crystals and preserve their morphology upon crystallization. This process produces biogenic crystals with a nanosphere particle morphology. Other biomineralization processes proceed by ion-by-ion growth, and some cases of biological crystal growth involve both processes. We also identify several biomineralization processes which do not seem to fit this working hypothesis. It is our hope that this highlight will inspire studies that will shed more light on the underlying crystallization mechanisms in biology.
    [Show full text]
  • An Overview of Biomineralization Processes and the Problem of The
    11 An Overview of Biomineralization Processes and the Problem of the Vital Effect Steve Weiner Department of Structural Biology Weizmann Institute of Science 76100 Rehovot Israel Patricia M. Dove Department of GeoSciences Virginia Tech Blacksburg, Virginia 24061 U.S.A. “Biomineralization links soft organic tissues, which are compositionally akin to the atmosphere and oceans, with the hard materials of the solid Earth. It provides organisms with skeletons and shells while they are alive, and when they die these are deposited as sediment in environments from river plains to the deep ocean floor. It is also these hard, resistant products of life which are mainly responsible for the Earth’s fossil record. Consequently, biomineralization involves biologists, chemists, and geologists in interdisciplinary studies at one of the interfaces between Earth and life.” (Leadbeater and Riding 1986) INTRODUCTION Biomineralization refers to the processes by which organisms form minerals. The control exerted by many organisms over mineral formation distinguishes these processes from abiotic mineralization. The latter was the primary focus of earth scientists over the last century, but the emergence of biogeochemistry and the urgency of understanding the past and future evolution of the Earth are moving biological mineralization to the forefront of various fields of science, including the earth sciences. The growth in biogeochemistry has led to a number of new exciting research areas where the distinctions between the biological, chemical, and earth sciences disciplines melt away. Of the wonderful topics that are receiving renewed attention, the study of biomineral formation is perhaps the most fascinating. Truly at the interface of earth and life, biomineralization is a discipline that is certain to see major advancements as a new generation of scientists brings cross-disciplinary training and new experimental and computational methods to the most daunting problems.
    [Show full text]
  • Effect of Ph Change on Exoskeletons of Selected Saltwater Organisms Which Rely on Calcium Fixation Derya Z
    Journal of Emerging Investigators Effect of pH change on exoskeletons of selected saltwater organisms which rely on calcium fixation Derya Z. Tansel1, Ariadna Arreaza2, Berrin Tansel2 1 Coral Gables Senior High, Coral Gables, FL 2 Florida International University, Miami, FL Summary increase in H+ concentration in the last 200 years (1,2,3). The projections for rising atmospheric carbon dioxide According to atmospheric CO2 projections, ocean surface concentrations indicate that the pH levels of the ocean pH levels are estimated to decrease by 0.3-0.4 units by surface could decrease by 0.3-0.4 units by the end of the end of the 21st century. This decrease corresponds the 21st century. The objective of this research was to to an increase in the hydrogen ion concentration of about evaluate the effect of pH on the exoskeletons of six aquatic organisms commonly found in South Florida 100-150% above the levels in the late 1800s (4,5). The coastal waters. The exoskeleton samples studied were impacts of ocean acidification can be 10–50% higher from the common nutmeg (Cancellaria reticulate), near coastal areas due to proximity to anthropogenic lettered olive (Oliva sayana), stiff pen shell (Atrina rigida), sources (6). kitten’s paw (Plicatulidae), fan coral (Gorgonia ventalina), Although some species can tolerate pH changes, and common slipper shell (Crepidula fornicate). The many marine organisms and processes can be impacted, exoskeleton samples were exposed to saltwater (34% including the composition of communities and food webs salinity) at pH levels ranging from 8.3 to 6.0 for 5 days.
    [Show full text]
  • Biomineralization and Evolutionary History Andrew H
    1 111 Biomineralization and Evolutionary History Andrew H. Knoll Department of Organismic and Evolutionary Biology Harvard University Cambridge, Massachusetts, 02138 U.S.A. INTRODUCTION The Dutch ethologist Niko Tinbergen famously distinguished between proximal and ultimate explanations in biology. Proximally, biologists seek a mechanistic understanding of how organisms function; most of this volume addresses the molecular and physiological bases of biomineralization. But while much of biology might be viewed as a particularly interesting form of chemistry, it is more than that. Biology is chemistry with a history, requiring that proximal explanations be grounded in ultimate, or evolutionary, understanding. The physiological pathways by which organisms precipitate skeletal minerals and the forms and functions of the skeletons they fashion have been shaped by natural selection through geologic time, and all have constrained continuing evolution in skeleton-forming clades. In this chapter, I outline some major patterns of skeletal evolution inferred from phylogeny and fossils (Figure 1), highlighting ways that our improving mechanistic knowledge of biomineralization can help us to understand this evolutionary record (see Leadbetter and Riding 1986; Lowenstam and Weiner 1989; Carter 1990; and Simkiss and Wilbur 1989 for earlier reviews). Figure 1. A geologic time scale for the past 1000 million years, showing the principal time divisions used in Earth science and the timing of major evolutionary events discussed in this chapter. Earlier intervals of time—the Mesoproterozoic (1600–1000 million years ago) and Paleoproterozoic (2500– 1600 million years ago) eras of the Proterozoic Eon and the Archean Eon (> 2500 million years ago)— are not shown. Time scale after Remane (2000).
    [Show full text]
  • Biomineralization & Biominerals “It's a Hard Life”
    Maria Isabel López Fierro Biomineralization Literature Review & Biominerals Chair: Marc A. Meyers “It’s a hard life” Joanna McKittrick Jan Talbot Image credit: Out Of The Blue Aquaculture Ltd 1 Outline Sponge Spicule Introduction & History Basic Biomineralization Principles Saturation, Nucleation, Growth, & Organic Matrix Image credit: http://www.choijinhyuk.com Bleached Coral Biominerals & Biomineralization Models Calcium Carbonate Shells: Nacre Silica Image credit: jroy.abenaza.com2 Sponge Spicule Hydroxyapatite Bone Why do we need to understand biomineralization? Summary & Conclusions Introduction & History of Biomineralization 3 Introduction: The Process Biomineralization is the process by which living form and influence the precipitation of minerals. 5µm No single or ‘grand’ •Crystals from the inner shell layer of the Eastern mechanism. oyster onto a metal implant. •sheets converge forming a“rosette” structure. Combination of efforts •Organic matrix appears like “glue.” from cells, producing Image credit: http://www.scienceasart.org organic and inorganic Skinner and Jahren (2003)4 molecules that combine in various structural ways to form an unique material. Introduction: Why mineralize? Evolution of Biomineralization has provided organisms with a strong building material. o Minerals are stiff and brittle (& cheap energy wise) o Organic materials are soft and pliable Functions include: v Strength & Integrity v Protection. v Mobility v Storage - Biominerals are ion reservoir for cellular functions. v Cutting and grinding v Buoyancy v Optical, magnetic and gravity sensing 5 History of biominerals First biomineralization evidence from microbial stromatolites - 3500M years ago Not controlled deposition of inorganic solids 560M years ago - organisms from different phyla evolved the ability Runnegar and Bengtson (1992) to form different minerals. To date there are 64+ 6 biominerals identified.
    [Show full text]
  • An Introduction to Biomineralization
    MATERIAL SCIENCE MEETS MEDICINE – PRESENTATION ABSTRACTS BIOMINERALIZATION An Introduction to Biomineralization John Dunlop Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam-Golm Many living organisms, ranging from bacteria to plants to animals, can control the formation of mineral both within and around their cells. These bio-minerals play important functional roles in organisms. The most obvious function is structural, with nano-sized mineral particles reinforcing our bones being a well- known example. Biominerals are also used in living systems in many other ways. To name just a few examples; they are used as transparent lenses as well as magnetic sensors and they also store important ions such as calcium used in the metabolism. All of these different functions arise through the exquisite control of the biomineralization process. Nature forms these minerals in incredibly complex shapes, with well-defined sizes and in addition can control what phase of mineral is formed (crystalline or amorphous for example). As such much research has been done to understand the process of biomineralization particularly with its application in the bioinspired design of novel materials. In medicine, and especially in the field of bone biology knowledge of how bone mineral forms is fundamental in the understanding, treatment and control of degenerative diseases such as osteoporosis. This presentation will give a general overview of the concept of biomineralization, and its application to medicine. The idea is to firstly present the evolutionary background of minerals in biology, showing a variety of examples from all domains of life. The presentation will then focus on giving a short summary of how mineralized tissues form, and then give an overview on how minerals organisation controls the tissue mechanical properties.
    [Show full text]
  • Remineralization of Demineralized Dentin Using a Dual-Analog System
    Remineralization of demineralized dentin using a dual-analog system N Saxena1 S Habelitz2 GW Marshall2 LB Gower1 1 – Materials Science and Engineering, University of Florida, Gainesville, FL, USA 2 – Preventative and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA, USA Correspondence to: Laurie Gower Materials Science and Engineering University of Florida 549 Gale Lemerand Dr. Gainesville, FL 32611 [email protected] 1 Abstract Objectives Improved methods are needed to remineralize dentin caries in order to promote conservation of dentin tissued and minimize the surgical interventions that are currently required for clinical treatment. Here we test the hypothesis that bulk substrates can be effectively mineralized via a dual- analog system proposed by others, using a tripolyphosphate “templating analog” and a poly(acrylic acid) or poly(aspartic acid) “sequestration analog”, the latter of which generates the polymer-induced liquid-precursor (PILP) mineralization process studied in our lab. Material & Methods – Demineralized human dentin slices were remineralized with and without pre-treatment with tripolyphosphate. Both poly(acrylic) acid and poly(aspartic acid) were used as PILP process-directing agents or “sequestration analogs”. A control experiment with no polymer present was also conducted. Results – No mineralization was observed in any of the poly(acrylic acid) groups. In both the poly(aspartic acid) and no polymer groups, tripolyphosphate inhibited mineralization on the surfaces of the specimens and promoted mineralization within the interiors of the specimens. Pre- treatment with tripolyphosphate enhanced overall mineralization of the poly(aspartic acid) group. However, when analyzed via TEM, regions with little mineral were still present. Conclusion – Poly(acrylic acid) was unable to remineralize demineralized dentin slices, even when pre-treated with tripolyphosphate.
    [Show full text]
  • Biomineralization of Collagen-Based Materials for Hard Tissue Repair
    International Journal of Molecular Sciences Review Biomineralization of Collagen-Based Materials for Hard Tissue Repair Le Yu 1 and Mei Wei 1,2,* 1 Department of Chemical and Biomolecular Engineering, Ohio University, Athens, OH 45701, USA; [email protected] 2 Department of Mechanical Engineering, Ohio University, Athens, OH 45701, USA * Correspondence: [email protected]; Tel.: +1-740-593-1474 Abstract: Hydroxyapatite (HA) reinforced collagen fibrils serve as the basic building blocks of natural bone and dentin. Mineralization of collagen fibrils play an essential role in ensuring the structural and mechanical functionalities of hard tissues such as bone and dentin. Biomineraliza- tion of collagen can be divided into intrafibrillar and extrafibrillar mineralization in terms of HA distribution relative to collagen fibrils. Intrafibrillar mineralization is termed when HA minerals are incorporated within the gap zone of collagen fibrils, while extrafibrillar mineralization refers to the minerals that are formed on the surface of collagen fibrils. However, the mechanisms re- sulting in these two types of mineralization still remain debatable. In this review, the evolution of both classical and non-classical biomineralization theories is summarized. Different intrafibrillar mineralization mechanisms, including polymer induced liquid precursor (PILP), capillary action, electrostatic attraction, size exclusion, Gibbs-Donnan equilibrium, and interfacial energy guided theories, are discussed. Exemplary strategies to induce biomimetic intrafibrillar mineralization using non-collagenous proteins (NCPs), polymer analogs, small molecules, and fluidic shear stress are discussed, and recent applications of mineralized collagen fibers for bone regeneration and dentin repair are included. Finally, conclusions are drawn on these proposed mechanisms, and the future trend of collagen-based materials for bone regeneration and tooth repair is speculated.
    [Show full text]
  • Biomineralization, Biomimetic and Non- Classical Crystallization
    BiomineralizationBiomineralizationBiomineralization,,, biomimeticbiomimeticbiomimeticandand and nonnonnon--- classicalclassicalclassicalcrystallizationcrystallization crystallization WaysWaysWaystoto tounderstandunderstand understand thethethe synthesissynthesissynthesisandand and formationformationformation mechanismsmechanismsmechanismsofof of complexcomplexcomplex materialsmaterialsmaterials HelmutHelmut CölfenCölfen Max-Planck-Institute of Colloids & Interfaces, Colloid Chemistry, Research Campus Golm, D-14424 Potsdam [email protected] CaCOCaCOCaCO333 BiomineralsBiomineralsBiominerals Coccolith (Calcite) Nacre (Aragonite) Herdmania momus (Vaterite) Characteristics of Biominerals: Complex forms generated from inorganic systems with simple structure Characteristics of inorganic crystals: Simple geometrical form but often complicated crystal structure Default: Rhombohedral Calcite ImportantImportantImportantbiomineralsbiominerals biominerals MineralMineral FormulaFormula FunctionFunction Calciumcarbonate CaCO3 Calcite Algae / Exoskeleton Birds / Eggshell Aragonite Fishes / Gravity sensor Mussels / Exoskeleton Vaterite Sea urchins / Spikes Calciumphosphate Hydroxyapatite Ca10(PO4)6(OH)2 Vertebrates / Skeleton, teeth Octa-Calciumphosphate Ca8H2(PO4)6 Vertebrates / Precursor for bone formation Silica SiO2 Algae / Exoskeleton Iron oxide Magnetite Fe3O4 Salmon, Tuna & bacteria / Magnetic field sensor Chitons / teeth EvolutionEvolutionEvolution ofofof aaa musselmusselmussel shellshellshell SEM of broken mussel shell SEM of broken
    [Show full text]
  • Terraced Iron Formations: Biogeochemical Processes Contributing to Microbial Biomineralization and Microfossil Preservation
    geosciences Article Terraced Iron Formations: Biogeochemical Processes Contributing to Microbial Biomineralization and Microfossil Preservation Jeremiah Shuster 1,2,* , Maria Angelica Rea 1,2 , Barbara Etschmann 3, Joël Brugger 3 and Frank Reith 1,2 1 School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia; [email protected] (M.A.R.); [email protected] (F.R.) 2 CSIRO Land and Water, Contaminant Chemistry and Ecotoxicology, PMB2 Glen Osmond, South Australia 5064, Australia 3 School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria 3800, Australia; [email protected] (B.E.); [email protected] (J.B.) * Correspondence: [email protected]; Tel.: +61-8-8313-5352 Received: 30 October 2018; Accepted: 10 December 2018; Published: 13 December 2018 Abstract: Terraced iron formations (TIFs) are laminated structures that cover square meter-size areas on the surface of weathered bench faces and tailings piles at the Mount Morgan mine, which is a non-operational open pit mine located in Queensland, Australia. Sampled TIFs were analyzed using molecular and microanalytical techniques to assess the bacterial communities that likely contributed to the development of these structures. The bacterial community from the TIFs was more diverse compared to the tailings on which the TIFs had formed. The detection of both chemolithotrophic iron-oxidizing bacteria, i.e., Acidithiobacillus ferrooxidans and Mariprofundus ferrooxydans, and iron-reducing bacteria,
    [Show full text]