Octacalcium phosphate – a metastable mineral phase controls the evolution of scaffold forming proteins

Pompe, W.; Worch, H.; Habraken, Wouter J. E. M.; Simon, Paul; Kniep, Rüdiger; Ehrlich, Hermann; Paufler, P.

doi:10.1039/c5tb00673b

Cited by 45 publications

(27 citation statements)

References 63 publications

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“…It is the main component of bone and teeth 5a. in which collagen molecules were found as a scaffold assisting the formation of hydroxyapatite nanocrystals . Most of the toughness in bone is contributed by the collagen phase, while the energy dissipation or deformation mechanisms of hydroxyapatite nanocrystals remains unknown .…”

Section: Atomic Scalementioning

confidence: 99%

Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

et al. 2019

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Biological materials found in Nature such as nacre and bone are well recognized as light-weight, strong, and tough structural materials. The remarkable toughness and damage tolerance of such biological materials are conferred through hierarchical assembly of their multiscale (i.e., atomicto macroscale) architectures and components. Herein, the toughening mechanisms of different organisms at multilength scales are identified and summarized: macromolecular deformation, chemical bond breakage, and biomineral crystal imperfections at the atomic scale; biopolymer fibril reconfiguration/deformation and biomineral nanoparticle/nanoplatelet/ nanorod translation, and crack reorientation at the nanoscale; crack deflection and twisting by characteristic features such as tubules and lamellae at the microscale; and structure and morphology optimization at the macroscale. In addition, the actual loading conditions of the natural organisms are different, leading to energy dissipation occurring at different time scales. These toughening mechanisms are further illustrated by comparing the experimental results with computational modeling. Modeling methods at different length and time scales are reviewed. Examples of biomimetic designs that realize the multiscale toughening mechanisms in engineering materials are introduced. Indeed, there is still plenty of room mimicking the strong and tough biological designs at the multilength and time scale in Nature.

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Section: Atomic Scalementioning

confidence: 99%

Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

et al. 2019

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“…The use of autograft tissue (taken from patient) causes the morbidity due to a second surgical site, while the application of allograft (another person's tissue) poses the risk of potential disease transmission and tissue rejection [1,2]. Due to such significant drawbacks of autograft and allograft applications it is crucial to search for efficient biomimetic materials [3][4][5][6] and structures [7][8][9], suitable for skeletal repair without inherent problems.…”

Section: Introductionmentioning

confidence: 99%

Surface-Dependent Osteoblasts Response to TiO2 Nanotubes of Different Crystallinity

et al. 2020

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One of the major challenges of implantology is to design nanoscale modifications of titanium implant surfaces inducing osseointegration. The aim of this study was to investigate the behavior of rat osteoblasts cultured on anodized TiO2 nanotubes of different crystallinity (amorphous and anatase phase) up to 24 days. TiO2 nanotubes were fabricated on VT1–0 titanium foil via a two-step anodization at 20 V using NH4F as an electrolyte. Anatase-phase samples were prepared by heat treatment at 500 °C for 1 h. VT1–0 samples with flat surfaces were used as controls. Primary rat osteoblasts were seeded over experimental surfaces for several incubation times. Scanning electron microscopy (SEM) was used to analyze tested surfaces and cell morphology. Cell adhesion and proliferation were investigated by cell counting. Osteogenic differentiation of cells was evaluated by qPCR of runt-related transcription factor 2 (RUNX2), osteopontin (OPN), integrin binding sialoprotein (IBSP), alkaline phosphatase (ALP) and osteocalcin (OCN). Cell adhesion and proliferation, cell morphology and the expression of osteogenic markers were affected by TiO2 nanotube layered substrates of amorphous and anatase crystallinity. In comparison with flat titanium, along with increased cell adhesion and cell growth a large portion of osteoblasts grown on the both nanostructured surfaces exhibited an osteocyte-like morphology as early as 48 h of culture. Moreover, the expression of all tested osteogenic markers in cells cultured on amorphous and anatase TiO2 nanotubes was upregulated at least at one of the analyzed time points. To summarize, we demonstrated that amorphous and anodized TiO2 layered substrates are highly biocompatible with rat osteoblasts and that the surface modification with about 1500 nm length nanotubes of 35 ± 4 (amorphous phase) and 41 ± 8 nm (anatase phase) in diameter is sufficient to induce their osteogenic differentiation. Such results are significant to the engineering of coating strategies for orthopedic implants aimed to establish a more efficient bone to implant contact and enhance bone repair.

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“…Based on the steady-state pH ($4 h), we also assume that the aqueous solutions have also reached chemical equilibrium in terms of aqueous calcium and orthophosphate speciation. The co-occurrence of OCP and HAP phases is ubiquitous during synthetic growth of Ca-phosphates due to the structural similarity between HAP and OCP, which consists of alternating domains of HAP and of structural water (Zhan et al, 2005;Pompe et al, 2015). As a result, these phases can form lamellar mixtures and easily undergo epitaxial growth (Brown et al, 1962;Fernandez et al, 2003).…”

Section: àmentioning

confidence: 99%

Mineralogical, nanostructural, and Ca isotopic evidence for non-classical calcium phosphate mineralization at circum-neutral pH

Schilling

Brown

Lammers

2018

Geochimica et Cosmochimica Acta

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Growth pathways of calcium (Ca) phosphate minerals are still under debate, but non-classical growth pathways, which encompass any mode of growth involving attachment of primary particles instead of monomer ions, are currently thought to dominate over classical mechanisms under a wide range of growth conditions. Cation desolvation during ion-by-ion growth is associated with the preferential uptake of isotopically light Ca in Ca-bearing phases, so the Ca isotope composition of Cabearing minerals can help to elucidate the dominant growth mechanism. Here, we combine stable Ca isotope analysis with mineralogical characterization and nanoscale imaging of growth features to determine for the first time the rate-dependent Ca isotope fractionation during seeded growth of hydroxyapatite (HAP) involving an octacalcium phosphate (OCP) precursor. Our data reveal that growth rates are strongly attenuated by pH, and that Ca isotope fractionation between the solid and growth solution is independent of growth rate between 1.9 Â 10 À9 and 2.8 Â 10 À8 mol Ca m À2 s À1. Moreover, nanoscale images of surface topography reveal direct deposition of primary particles on the HAP seed surface following sustained growth, providing visual evidence of a non-classical growth pathway. Together, these findings support the hypothesis that hydroxyapatite growth is dominantly non-classical. The process of cluster nucleation from the bulk solution and attachment of these clusters to the seeded HAP apparently does not involve a significant kinetic isotope effect, which implies that abiogenically formed Ca-phosphates likely preserve the Ca isotope composition of the fluid from which the crystals originated.

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Octacalcium phosphate – a metastable mineral phase controls the evolution of scaffold forming proteins

Abstract: The molecular structure of collagen is the result of evolutionary selection in the process of formation of calcium phosphate biocomposites.

Cited by 45 publications

References 63 publications

Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

Surface-Dependent Osteoblasts Response to TiO2 Nanotubes of Different Crystallinity

Mineralogical, nanostructural, and Ca isotopic evidence for non-classical calcium phosphate mineralization at circum-neutral pH

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