Papers by Keyword: Biomineralization

Abstract: Layered double hydroxides (LDHs) materials are widely used in the cathodes of high-performance supercapacitors. However, current preparation methods suffer from issues such as high energy consumption, complex processes, and significant safety hazards. In this study, based on a mild biomineralization reaction route, flower-like nano-sheet structured cobalt-based LDHs (COH) cathode was successfully prepared. The COH cathode achieved an outstanding specific capacitance of 829.0 F g^-¹ at a current density of 1 A g^-¹ and retained 90.9% of its initial capacitance after 4000 cycles. This biomineralization strategy holds promise for widespread application in the preparation of nanostructured electrode materials.

Abstract: Calcium phosphate is a natural biomineral and the major inorganic constituent of bones and teeth. Therefore, synthetic calcium phosphates that mimic the biogenic ones possess excellent biocompatibility as well as biodegradability and are promising materials for medicine. Due to their unique physiochemical properties, calcium phosphate nanoparticles (CaP NPs) are extensively exploited in nanomedicine as carriers of biomolecules, including peptides, proteins, and nucleic acids. In this regard, peptides are of particular interest as they are exceptionally selective and efficacious for the treatment of a broad range of diseases. Among various peptides for biomedical applications, cardio-specific peptides are particularly interesting since they represent a valuable alternative to conventional treatments. Moreover, they can contribute to overcome important clinical limitations, including drug resistance and non-specific biodistribution of traditional drug products. In this work, we have investigated the loading of a therapeutic mimetic peptide, which was previously shown to improve myocardial contraction and results in the restoration of cardiac function. Peptide-loaded CaP NPs were prepared by exploiting a biomineralization approach, by using a mineralizing solution containing Ca²⁺, Mg²⁺, and PO₄^3- ions. Several experimental conditions were tested by varying the reaction time, as well as the drug concentration. Colloidal stability, morphology, size, as well as drug loading were evaluated to identify the best candidate to be tested in vitro in the future.

Abstract: The paper presents the results of the assessment of the effect of bacterial microorganism Sporosarcina pasteurii and CaCl₂ and CH₄N₂O precursors as agents initiating carbonate mineralization processes on the construction and technical properties of binders. In order to achieve this, a preliminary bacterial solution with precursors was prepared, which was introduced into the system instead of mixing water in the range of 0–10% with interval of 2%. The effect of the bacterial solution as a complex additive on the physical and mechanical properties of cement paste and stone is shown: normal density, setting time, water segragation, strength in compression and bending. The introduction of the solution provides a reduction in the setting time of cement without loss of strength both at the initial and at the final stages of hardening.

Abstract: In-vitro experiment method was used to study biomineralization properties of carbonate apatite bulk and electrophoresis coating with different carbonate contents. The mineralization processes in SBF solution were investigated by means of XRD, SEM and so on. Research results show that the apatite with poor crystallization and small grain size induced by the carbonate substitution is beneficial to the sintering of the bulk and the formation of the bone-like hydroxyl-carbonate apatite (HCA) layer on the surface after soaking in the SBF. However, the carbonate substitution greatly reduces the pore size and porosity of coating, which is not conducive to the deposition and growth of the mineralized layer, thus weakens the biomineralization properties of the coating.

Abstract: We have focused on the metal-reducing bacterium, Shewanella algae that are able to reduce and deposit platinum group metals (Pt (IV), Pd (II) and Rh (III)) and gold (Au (III)) in neutral solutions at room temperature under anaerobic conditions. When processing the aqua regia solution of spent automotive catalysts, the solution pH was adjusted to the optimal range for S. algae activity between pH 4 and 7. After this pH adjustment, the S. algae cells were able to rapidly and selectively reduce and accumulate the platinum group metal ions from the leaching solution into the bacterial cells as metallic nanoparticles. The biotechnological procedure also has the potential to allow the recovery of Au (III) ions from the leaching solution of electronic waste. We also found that the S. algae cells were also applicable to the adsorption of rare metal ions from acidic solutions. We achieved selective adsorption of indium (In (III)) ions on the bacterial cells from the leaching solution of waste liquid crystal displays by adjusting its pH, because the pH range necessary for S. algae to act as an effective adsorbent differs for different metal ions. Our proposed microbial methods enable the rapid and highly efficient recovery of precious and rare metals sourced from post-consumer products.

Abstract: Biomineralization is the process by which living systems produce minerals. At theEuropean scale, this particular scientific field associates researchers of diverse horizons,ranging from zoology, mineralogy, palaeontology, and environmental sciences to materialssciences, dentistry and bone surgery. In this context, the COST Action TD0903, also referredas Biomineralix, was set up in November 2009 under the auspices of the COST Office inBrussels. This scientific network was active during four and half years, until May 2014. Itassociated 17 European countries, and a total of 29 laboratories. Its main objectives weremultiple: 1. To promote biochemical and proteomic research on the biomineralisationprocesses of diverse biological models, ranging from microorganisms to metazoans, such asmolluscs or sea urchins. 2. To characterize biominerals owing to the most advancedbiochemical and biophysical techniques. 3. To use natural biominerals as sentinels to recordenvironmental parameters and pollutions in terrestrial, riverine or marine ecosystems. 4. Totake lessons from natural systems to generate novel biomimetic or bioinspired materials,according to soft chemical processes. These research trends organized the action in fourworking groups. The present paper evaluates four and half years of functioning of thenetwork. It reviews some of the major results, in particular those acquired in the frame ofShort-Term Scientific Missions (STSMs), and lists the corresponding scientific papers.

Abstract: Mollusc shells are organic-inorganic composites that are often preserved in the fossil record. However, the way the organic fraction, also called shell matrix, gets fossilized remains an unsolved question, in spite of several old and more recent studies. In the present paper, we have tried to mimic a diagenetic process by constantly heating for ten days at 100°C fresh nacre powder samples of the Polynesian pearl oyster Pinctada margaritifera. Each day, aliquots of nacre powder were sampled and the matrix was subsequently extracted. It was further analysed by direct weigh quantification, by immunological techniques and by proteomics. Our preliminary data suggest that nacre proteins, when heated at 100°C in dry condition, degrade rather slowly. We evidenced a differential degradation pattern of the soluble and insoluble fractions, and showed that some nacre proteins of the insoluble fraction are stable after ten days of heating. Factors that influence the diagenetic stability of some shell proteins are discussed.

Abstract: The surface membrane is a lamellar structure exclusive of gastropods that is formed during the shell secretion. It protects the surface of the growing nacre and it is located between the mantle epithelium and the mineralization compartment. At the mantle side of the surface membrane numerous vesicles provide material, and at the nacre side, the interlamellar membranes detach from the whole structure. Components of nacre (glycoproteins, polysaccharides and calcium carbonate) cross the structure to reach the mineralization compartment, but the mechanism by which this occurs is still unknown. In this paper we have investigated the ultrastructure of the surface membrane and the associated vesicle layer by means of Transmission Electron Microscopy. Electron Energy Loss Spectroscopy and Energy-dispersive X-ray Spectroscopy were used for elemental analysis. The analyses revealed the concentration of calcium in the studied structures: vesicles, surface membrane, and interlamellar membranes. We discuss the possible linkage of calcium to the organic matrix.

Abstract: High-throughput approaches such as genomics, transcriptomics and proteomics have led to the discovery of a larger set of biomineralization genes than previously foreseen. These gene lists are often difficult to decode in light of the current models of calcification. Here we overview the proteins available in UniProt (Universal Protein Resource), that were identified directly in metazoan calcium carbonate mineralized structures or known to have direct key-functions in calcification processes. Functional annotation of the protein datasets using Gene Ontology reveals that functions like carbohydrate binding, structural and catalytic activities (e.g. hydrolase) are commonly represented across the organic matrices.

Abstract: We revisit the ultrastructural features of different calcareous biominerals and identify remarkable similarities: taxonomically very distant species show a common nanogranular structure, even if different extracellular secretion patterns are employed or calcium carbonate polymorphs formed. By these analyses, we elucidate the locus of the small fraction of intracrystalline organic matrix revealing its intergranular character and localize the intracrystalline amorphous calcium carbonate moiety commonly found in mesocrystalline biominerals and provide a first explanation for the pathway by which it is preserved.