Search results for "Biomineralization"
showing 10 items of 131 documents
Stable amorphous calcium oxalate: synthesis and potential intermediate in biomineralization.
2014
Amorphous calcium oxalate nanoparticles with sizes of 10–30 nm were synthesized at room temperature by the hydrolysis of a dimethyl oxalate from ethanol solution.
Enzymatically Synthesized Inorganic Polymers as Morphogenetically Active Bone Scaffolds
2014
In recent years a paradigm shift in understanding of human bone formation has occurred that starts to change current concepts in tissue engineering of bone and cartilage. New discoveries revealed that fundamental steps in biomineralization are enzyme driven, not only during hydroxyapatite deposition, but also during initial bioseed formation, involving the transient deposition and subsequent transformation of calcium carbonate to calcium phosphate mineral. The principal enzymes mediating these reactions, carbonic anhydrase and alkaline phosphatase, open novel targets for pharmacological intervention of bone diseases like osteoporosis, by applying compounds acting as potential activators of …
Effect of bioglass on growth and biomineralization of SaOS-2 cells in hydrogel after 3D cell bioprinting.
2014
We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP …
Snapshots of calcium carbonate formation – a step by step analysis
2017
Abstract Recent advances in our understanding of CaCO3 nucleation from solution have provoked new and challenging questions. We have studied CaCO3 formation using precipitation by carbonate ester hydrolysis which ensures precipitation from a strictly homogeneous solution state and allows “titrating” carbonate to a solution with a given Ca2+ concentration on a timescale suited for kinetic studies. Nucleation and crystallization were traced by combining dynamic light scattering (DLS) and transmission electron microscopy (TEM). DLS served as in situ technique to identify the nucleation time, to monitor particle size evolution, to discriminate different precipitation mechanisms and to validate …
Template induced crystallization of biominerals on self-assembled monolayers of alkylthiols
1998
Abstract We have studied the templated crystallization of the three polymorphs of calcium carbonate on self-assembled monolayers of ω -substituted alkylthiols on gold surfaces. Our interest has been to model biomineralization processes by examining the effect of structured organic templates on heterogeneous nucleation at the inorganic–organic interphase. The crystallization of the three polymorphs was carried out from solution at two different temperatures. The crystals that were formed on the surface were examined using scanning electron microscopy. Phase quantification was achieved through Rietveld analysis of the X-ray diffraction profiles. This study provides significant clues on factor…
Growing and Shaping Metal–Organic Framework Single Crystals at the Millimeter Scale
2020
Controlling and understanding the mechanisms that harness crystallization processes is of utmost importance in contemporary materials science and, in particular, in the realm of reticular solids where it still remains a great challenge. In this work, we show that environments mimicking microgravity conditions can harness the size and shape of functional biogenic crystals such as peptide-based metal–organic frameworks (MOFs). In particular, we demonstrate formation of the largest single crystals with controlled nonequilibrium shapes of peptide-based MOFs reported to date (e.g., those featuring curved crystal habits), as opposed to the typical polyhedral microcrystals obtained under bul…
Biomineralisations in crustaceans: storage strategies
2004
Abstract Crustaceans are a remarkable group of animals because of their ability to elaborate cyclically two kinds of calcified biomineralisations: an unstretchable exoskeleton (or cuticle) and also, for many species, depending of the way of life of the considered animal, transitory calcium deposits. They are in consequence subjected to a cyclic life and notably, to a periodical balance between two sources of calcium, exogenous and/or endogenous. The storage structures, essentially composed of calcium carbonate precipitated within a proteinaceous organic matrix, are very diversified. The calcium carbonate of the cuticle of most of the species is under a crystalline state and/or an amorphous …
Discovery of Ca oxalate crystals associated with fungi in moss travertines (Bryoherms, freshwater heterogeneous stromatolites)
1995
Buffered decalcification of live moss and liverwort (Hepaticae) travertines resulted in the release of a large number of organisms (bacteria, cyanobacteria, fungi, eukaryotic algae, and small animals), which constitute an “organic mat”; (also called an algal mat or biofilm). This mat is calcified and commonly has laminations, allowing moss travertines to be considered as stromatolitic structures. After decalcification of 300 samples of travertines (using dilute acetic acid), only 9 released Ca oxalate crystals in the form of needle bundles, spherulites, and tetragonal bipyramidal prisms. These crystalline forms are identical to those found in some phanerophytes and soils. Mycelian filaments…
Experimental modeling of bacterially-induced Ca carbonate precipitation: new insights on possible mechanisms.
2015
The contribution of microorganisms, particularly bacteria, in carbonate mineral formation, the main natural processes controlling CO2 level in the atmosphere, has played an important role since the Archean Eon. In this study we review our recent experimental work on CaCO3 precipitation induced by two anoxygenic phototrophic bacteria (APB), Rhodovulum steppense A-20sT and Rhodovulum sp. S-17-65, and by cyanobacteria Gloeocapsa sp. f-6gl. These bacteria are representatives of two important groups of photosynthetic organisms present at the Earth surface both in the past and at the present times. The mechanisms of organomineralization deriving from APB and cyanobacteria activities are drastical…
Biofabrication of biosilica-glass by living organisms
2008
Biosilicification is an evolutionarily old and widespread type of biomineralization both in unicellular and multicellular organisms, including sponges, diatoms, radiolarians, choanoflagellates, and higher plants. In the last few years combined efforts in molecular biology, cell biology, and inorganic and analytical chemistry have allowed the first insight into the molecular mechanisms by which these organisms form an astonishing variety of siliceous structures that cannot be achieved by chemical methods. Here we report about the present stage of knowledge on structure, biochemical composition, and mechanisms of biosilica formation, focusing our attention particularly on sponges because of t…