Composition Of Biominerals Research Articles

Organochlorine Exposure Influences the Cellular Morphology of Red Algae Eucheuma denticulatum (N.L. Burman) Collins & Hervey, 1917

Higlight Research The research demonstrates the negative impact of organochlorine content on the morphological structure and biomineral composition of E. denticulatum, highlighting the need for effective measures to prevent and reduce organochlorine pollution in marine environments. Further research could focus on specific mechanisms of organochlorine toxicity and potential remediation strategies. Abstract Organochlorine compounds not only pollute marine waters but also interfere with the survival of marine biota. Organochlorine compounds absorbed by organisms disrupt metabolism and inhibit cellular functions. The implication of this research is to prevent and reduce the disposal of organochlorines into the environment because they can accumulate in soil, water, and air, remaining for years in the environment. This accumulation can affect food chains and negatively affect ecosystems and marine animals.This research aimed to investigate the impact of organochlorine content on the surface morphology and biomineral characteristics of the red alga E. denticulatum cells. Electron Microscope (SEM) analysis was used to observe particle morphology surfaces down to 1 nm, while Energy Dispersive Spectroscopy (EDS) was used to analyze the specimens' element composition and chemical characteristics. Energy Dispersive Spectroscopy (EDS) analysis revealed that red algae had the highest content of Chlorine (Cl) at 57.20%, followed by Sodium (Na) at 34.84%, Oxygen (O) at 5.21%, Calcium (Ca) at 1.64%, and the lowest element being Sulfur (S) at 1.11%. Overall, this research demonstrates the negative impact of organochlorine content on the morphological structure and biomineral composition of E. denticulatum, highlighting the need for effective measures to prevent and reduce organochlorine pollution in marine environments. Further research could focus on specific mechanisms of organochlorine toxicity and potential remediation strategies.

Biomineral-Based Composite Materials in Regenerative Medicine.

Regenerative medicine aims to address substantial defects by amplifying the body's natural regenerative abilities and preserving the health of tissues and organs. To achieve these goals, materials that can provide the spatial and biological support for cell proliferation and differentiation, as well as the micro-environment essential for the intended tissue, are needed. Scaffolds such as polymers and metallic materials provide three-dimensional structures for cells to attach to and grow in defects. These materials have limitations in terms of mechanical properties or biocompatibility. In contrast, biominerals are formed by living organisms through biomineralization, which also includes minerals created by replicating this process. Incorporating biominerals into conventional materials allows for enhanced strength, durability, and biocompatibility. Specifically, biominerals can improve the bond between the implant and tissue by mimicking the micro-environment. This enhances cell differentiation and tissue regeneration. Furthermore, biomineral composites have wound healing and antimicrobial properties, which can aid in wound repair. Additionally, biominerals can be engineered as drug carriers, which can efficiently deliver drugs to their intended targets, minimizing side effects and increasing therapeutic efficacy. This article examines the role of biominerals and their composite materials in regenerative medicine applications and discusses their properties, synthesis methods, and potential uses.

Novel Developments in Advanced Materials Fields: Porous and Non-Porous Biomaterials Used in Regenerative Medicine and Tissue Engineering

Abstract In this brief review, porous and non-porous biomaterials used as scaffolds in regenerative medicine and tissue engineering and new innovative techniques to obtain biomaterials were discussed. Various methods have been presented to obtain advanced materials used as scaffolds, such as (i) 3D printed biomineral composites obtained with bacteria-loaded ink (bactoInk), (ii) the use of vegetable waste, such as rice husks, parsley, spinach or cocoa in the development of bioplastics, (iii) the use of natural biological materials of animal origin (such as bovine bones, corals, snail shells or eggshells) from waste, or (iv) the creation of new biomaterials that can reduce or combat the infection of scaffolds after implantation.

3D printing of living structural biocomposites

Nature fabricates organic/inorganic composites under benign conditions, yet, in many cases, their mechanical properties exceed those of the individual building components it is made from. The secret behind the evolutionary pivot is the unique ability of nature to control structure and local composition of its materials. This tight control is often achieved through compartmentalization of the reagents that can be locally released. Inspired by nature, we introduce an energy-efficient process that takes advantage of the compartmentalization to fabricate porous CaCO3-based composites exclusively comprised of nature-derived materials whose compressive strength is similar to that of trabecular bones. The unique combination of nature-derived materials, 3D printability, and good mechanical properties is achieved through the formulation of these materials: We combine microgel-based granular inks that inherently can be 3D printed with the innate potential of engineered living materials to fabricate bacteria-induced biomineral composites. The resulting biomineral composites possess a porous trabecular structure that comprises up to 93 wt% CaCO3 and thereby can withstand pressures up to 3.5 MPa. We envisage this system to have the potential to be used in art restoration, serve as artificial corals to help the regeneration of marine reefs, and, with additional work, might even allow the reparation of broken or partially disintegrated natural mineral-based materials such as certain parts of bones.

Biominerals in the Cacteae tribe: Chemical-morphological characterization, distribution and systematic perspectives

• The occurrence of silica bodies in the hypodermis of cacti are diagnostic for all the species of Echinocactus , and the exclusion of E. grusonii of this genus is supported by the lack of silica bodies as well as the occurrence of calcium oxalate druses. • Six biomineral habits were found in the Cacteae species studies, being spherulites and prisms the most common. • Extracellular sandstones occur in six species of Mammillaria , commonly in the outer periclinal wall of the epidermis. • For the first time the structure of the biominerals of seven genera ( Cumarinia, Echinomastus, Escobaria, Obregonia, Sclerocactus , Stenocactus) of Cacteae are characterized. Biominerals precipitate by biological activity and are found in various organisms. In the Cactaceae family, biominerals have been described for numerous genera and species and their contribution to systematics has recently been demonstrated. The aims of this study are to characterize the biominerals in the stem of members of Cacteae by describing their shape, position and mineral composition. Twenty-eight genera and 149 species of Cacteae were studied by bright-field and polarized microscopy. The composition of biominerals was analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy in 34 species representing the Cacteae clades. The biominerals of seven genera out of 28 are described for the first time. Only six species of Mammillaria have extracellular biominerals. Sixteen genera and 91 species possess intracellular biominerals in hypodermis, where species of Echinocactus and Ferocactus showed silica bodies. Spherulites, prisms and druses are present in 28 genera, and are distributed in the cortex of 141 species and in the pith of 94 species. Statistical analysis revealed differences between genera for the maximum length of biominerals in the hypodermis and cortex. Notably, Kadenicarpus possesses the smallest biominerals in the cortex and pith (< 35 µm in mean) and the largest mean in the pith for Astrophytum (212 µm). In the Cacteae, calcium oxalates were the most predominant biominerals. Other elements such as magnesium, manganese, and aluminum were also identified. Lophophora is characterized by crystalline aggregates in the cortex of both species with calcium oxalate and traces of silicon and iron, which are not found in other crystalline aggregates of other taxa. We detected a unique combination of biominerals that allowed for us to distinguish the species of some genera, such as Astrophytum and Echinocactus . In conclusion, the occurrence, structure and size of biominerals provide valuable information for systematics at the generic level in Cacteae.

Determination of fluorine distribution in shark teeth by laser-induced breakdown spectroscopy.

Quantifying the chemical composition of fast-growing hard tissues in the environment can shed valuable information in terms of understanding ecosystems both prehistoric and current. Changes in chemical composition can be correlated with environmental conditions and can provide information about the organism's life. Sharks can lose 0.1 to 1.1 teeth/day, depending on species, which offers a unique opportunity to record environmental changes over a short duration of time. Shark teeth contain a biomineral phase that is made up of fluorapatite [Ca5(PO4)3F], and the F distribution within the tooth can be correlated to tooth hardness. Typically, this is determined by bulk acid digestion, energy-dispersive X-ray spectroscopy (EDS), or wavelength-dispersive spectroscopy. Here we present laser-induced breakdown spectroscopy (LIBS) as an alternative and faster approach for determining F distribution within shark teeth. Using a two-volume laser ablation chamber (TwoVol3) with innovative embedded collection optics for LIBS, shark teeth were investigated from sand tiger (Carcharias Taurus), tiger (Galeocerdo Cuvier), and hammerhead sharks (Sphyrnidae). Fluorine distribution was mapped using the CaF 603 nm band (CaF, Β 2Σ+ → X 2Σ+) and quantified using apatite reference materials. In addition, F measurements were cross referenced with EDS analyses to validate the findings. Distributions of F (603 nm), Na (589 nm), and H (656 nm) within the tooth correlate well with the expected biomineral composition and expected tooth hardness. This rapid methodology could transform the current means of determining F distribution, particularly when large sample specimens (350 mm2, presented here) and large quantities of specimens are of interest.

Changes in phytoplankton and biomineral content of particles during episodic fluxes to abyssal depth

AbstractLarge episodic pulses of particulate organic carbon (POC) at the deep‐sea (~ 4000 m) time‐series Sta. M in the Northeast Pacific Ocean have increased in frequency and magnitude over the past 32 years. We inferred the ecological drivers of these events by quantifying the phytoplankton and biomineral composition within particles collected by bottom‐moored sediment traps immediately before, during, and after 14 high‐flux events. Samples collected during high‐flux events contained a significantly different phytoplankton community from other sampling periods. These particles contained relatively fewer intact phytoplankton cells and a sustained contribution from fragmented diatom frustules from species typical in coastal blooms. Biomineral fluxes did not appear to be driving high‐flux events. We suggest that most of the observed high‐flux events were generated by offshore transport of coastal diatom blooms, but that these particles were also highly transformed by deep‐sea pelagic food webs before reaching bathypelagic depths.

Preliminary Data on Geochemical Characteristics of Major and Trace Elements in Typical Biominerals: From the Perspective of Human Kidney Stones

The chemical composition of biominerals is essential for understanding biomineral formation and is regarded as an attractive subject in bio-mineralogical research on human kidney stones (urinary calculi). In order to obtain more geochemically interpreted data on biogenic minerals, mineralogical compositions and major and trace element concentrations of sixty-six kidney stone samples derived from kidney stone removal surgeries were measured. Infrared spectroscopy results showed that calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) were the two main mineral components of kidney stones. Geochemical results indicated that major and trace element concentrations were present in the following order: Ca &gt; Mg &gt; Na &gt; K &gt; Zn &gt; Fe &gt; Pb &gt; Ba &gt; Cu &gt; Ti &gt; Mo &gt; Cd &gt; Cr. With the exception of Ca, Mg was the second-most abundant element. Zn exhibited higher concentrations relative to other trace elements, which suggests a potential substitution of calcium by metal ions with a similar charge and radius rather than by metals in kidney stone formation. Pb appeared in significantly higher concentrations than in previous studies, which indicates Pb enrichment in the environment. In order to discern multi-element relationships within kidney stones, principal component analysis was applied. Three principal components (PCs, eigenvalues &gt;1) were extracted to explain 64.4% of the total variance. The first component exhibited positively correlated Na-Zn-Cr-Mo-Cd-Pb, while the second component exhibited more positively weighted Mg-K-Ba-Ti. Fe-Cu demonstrated a positive correlation in the third component. This study suggests that Ca exhibits a preference for uptake by oxalates during human urinary stone crystallization, while other alkali metals and alkaline earth metals precipitate with phosphate.

Selective Adsorption of Amino Acids in Crystals of Monohydrocalcite Induced by the Facultative Anaerobic Enterobacter ludwigii SYB1

The morphology, crystal structure, and elemental composition of biominerals are commonly different from chemically synthesized minerals, but the reasons for these are not fully understood. A facultative anaerobic bacterium, Enterobacter ludwigii SYB1, is used in experiments to document the hydrochemistry, mineral crystallization, and cell surface characteristics of biomineralization. It was found that carbonate anhydrase and ammonia production were major factors influencing the alkalinity and saturation of the closed biosystem. X-ray diffraction (XRD) spectra showed that calcite, monohydrocalcite (MHC), and dypingite formed in samples with bacterial cells. It was also found that the (222) plane of MHC was the preferred orientation compared to standard data. Scanning transmission electron microscopy (STEM) analysis of cell slices provides direct evidence of concentrated calcium and magnesium ions on the surface of extracellular polymeric substances (EPS). In addition, high-resolution transmission electron microscopy (HRTEM) showed that crystallized nanoparticles were formed within the EPS. Thus, the mechanism of the biomineralization induced by E. ludwigii SYB1 can be divided into three stages: (i) the production of carbonate anhydrase and ammonia increases the alkalinity and saturation state of the milieu, (ii) free calcium and magnesium ions are adsorbed and chelated onto EPS, and (iii) nanominerals crystallize and grow within the EPS. Seventeen kinds of amino acids were identified within both biotic MHC and the EPS of SYB1, while the percentages of glutamic and aspartic acid in MHC increased significantly (p < 0.05). Furthermore, the adsorption energy was calculated for various amino acids on seven diffracted crystal faces, with preferential adsorption demonstrated on (111) and (222) faces. At the same time, the lowest adsorption energy was always that of glutamic and aspartic acid for the same crystal plane. These results suggest that aspartic and glutamic acid always mix preferentially in the crystal lattice of MHC and that differential adsorption of amino acids on crystal planes can lead to their preferred orientation. Moreover, the mixing of amino acids in the mineral structure may also have a certain influence on the mineral lattice dislocations, thus enhancing the thermodynamic characteristics.

Advanced characterization of biomineralization at plaque layer and inside rice roots amended with iron- and silica-enhanced biochar

Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates rice yield by increasing plant uptake of mineral nutrients. With alterations of the nutrient status in roots, element homeostasis (e.g., Fe) in the biochar-treated rice root was related to the formation of biominerals on the plaque layer and in the cortex of roots. However, the in situ characteristics of formed biominerals at the micron and sub-micron scale remain unknown. In this study, rice seedlings (Oryza sativa L.) were grown in paddy soil treated with BCF and conventional fertilizer, respectively, for 30 days. The biochar-induced changes in nutrient accumulation in roots, and the elemental composition, distribution and speciation of the biomineral composites formed in the biochar-treated roots at the micron and sub-micron scale, were investigated by a range of techniques. Results of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that biochar treatment significantly increased concentrations of nutrients (e.g., Fe, Si, and P) inside the root. Raman mapping and vibrating sample magnetometry identified biochar particles and magnetic Fe nanoparticles associated with the roots. With Fe plaque formation, higher concentrations of FeOx− and FeOxH− anions on the root surface than the interior were detected by time-of-flight secondary ionization mass spectrometry (ToF-SIMS). Analysis of data from scanning electron microscopy energy-dispersive spectroscopy (SEM-EDS), and from scanning transmission electron microscopy (STEM) coupled with EDS or energy electron loss spectroscopy (EELS), determined that Fe(III) oxide nanoparticles were accumulated in the crystalline fraction of the plaque and were co-localized with Si and P on the root surface. Iron-rich nanoparticles (Fe–Si nanocomposites with mixed oxidation states of Fe and ferritin) in the root cortex were identified by using aberration-corrected STEM and in situ EELS analysis, confirming the biomineralization and storage of Fe in the rice root. The findings from this study highlight that the deposition of Fe-rich nanocomposites occurs with contrasting chemical speciation in the Fe plaque and cortex of the rice root. This provides an improved understanding of the element homeostasis in rice with biochar-mineral fertilization.

Segmental long bone regeneration guided by degradable synthetic polymeric scaffolds.

ABSTRACTRecent developments in synthetic bone grafting materials and adjuvant therapeutic agents have opened the door to the regenerative reconstruction of critical-size long bone segmental defects resulting from trauma, osteoporotic fractures or tumour resections. Polymeric scaffolds with controlled macroporosities, degradability, useful surgical handling characteristics, and the ability to deliver biotherapeutics to promote new bone ingrowth have been developed for this challenging orthopaedic application. This review highlights major classes of degradable synthetic polymers and their biomineral composites, including conventional and amphiphilic polyesters, polyanhydrides, polycarbonates, and polyethylene glycol-based hydrogels, that have been explored for the regenerative reconstruction of critical-size long bone segmental defects over the past two decades. The pros and cons of these synthetic scaffold materials are presented in the context of enabling or impeding the functional (mechanical and radiographic) repair of a long bone segmental defect, with the long bone regeneration outcomes compared with healthy long bone controls or results achieved with current grafting standards.

Resolving Internal Structures and Composition of Biominerals: The Case of Calcitic Prisms of Mollusk Shells

Resolving Internal Structures and Composition of Biominerals: The Case of Calcitic Prisms of Mollusk Shells

The effect of biomineral composition on the biochemical parameters of animal blood

The article presents the results of scientific and experimental studies on the creation of a biomineral composition intended for the prevention of diseases and improve animal health. The possibility of creating biomineral compositions based on wormwood of bitter and siliceous rocks - flasks of Western Kazakhstan, taking into account their chemical, mineralogical and biological properties. Based on experimental studies, the choice of siliceous rock, flasks of the West Kazakhstan region, is scientifically justified by the criterion of a high content of amorphous and finely divided silica, which gives the following advantages: - highly dispersed silica, guarantees effective sorption of mycotoxins, salts of heavy metals, chemical toxins, radionuclides, gases and other metabolic products in the animal’s body due to the huge sorbing surface. Wormwood as a biological active component enhances immunity and acts as an antifungal, antimicrobial, anti-inflammatory agent. As a result of scientific and experimental work, it was found that the proposed biomineral composition has high biological activity and significant pharmacological action, which is manifested by an improvement in the morphological and biochemical parameters of the blood of cows.

Effect of Synthesis Medium on the Structure and Physicochemical Properties of Biomineral Composites Based on Hydroxyapatite and Hyaluronic Acid

Dispersions based on sodium hyaluronate and hydroxyapatite, which is synthesized both by the classical method in an aqueous medium to obtain submicron particles and in a bioactive hyaluronan medium with the formation of nanosized particles, are obtained. The synthesized hydroxyapatite nanoparticles have a complex structure based on a monodentate complex hyaluronan–Ca2+ which remains in the dispersion both when adding a hyaluronan solution and when diluted with water. Physicochemical methods show that there is a significant difference between the energy characteristics of the surfaces of biocomposites obtained from dispersions. The rheology of dispersions of hydroxyapatite micro- and nanoparticles is investigated, the effect of dispersed phase concentration on it is revealed, and the viscoplastic behavior of dispersions of microparticles is demonstrated. This behavior disappears upon addition of the hyaluronan solution, which, however, leads to the loss of stability by the system. The introduction of hydroxyapatite nanoparticle additives into hyaluronan solutions has a weak effect on the rheology; no flocculation of nanoparticles occurs. The resulting composites consisting of hydroxyapatite and sodium hyaluronate can be considered a basis of a drug for the rehabilitation treatment of periodontitis.

Kinetic and Metabolic Isotope Effects in Zooxanthellate and Non-zooxanthellate Mediterranean Corals Along a Wide Latitudinal Gradient

Many calcifying organisms exert significant biological control over the construction and composition of biominerals which are thus generally depleted in oxygen-18 and carbon-13 relative to the isotopic ratios of abiogenic aragonite. The skeletal δ18O and δ13C values of specimens of Mediterranean zooxanthellate (Balanophyllia europaea and Cladocora caespitosa) and non-zooxanthellate corals (Leptopsammia pruvoti and Caryophyllia inornata) were assessed along an 8° latitudinal gradient along Western Italian coasts, spanning ~2 °C and ~37 W m-2 of annual average sea surface temperature and solar radiation (surface values), respectively. Seawater δ18O and δ13CDIC were surprisingly constant along the ~850 km latitudinal gradient while a ~2 and ~4 ‰ variation in skeletal δ18O and a ~4 and ~9 ‰ variation in skeletal δ13C was found in the zooxanthellate and non-zooxanthellate species, respectively. Albeit Mediterranean corals considered in this study are slow growing, only a limited number of non-zooxanthellate specimens exhibited skeletal δ18O equilibrium values while all δ13C values in the four species were depleted in comparison to the estimated isotopic equilibrium with ambient seawater, suggesting that these temperate corals cannot be used for thermometry-based seawater reconstruction. Calcification rate, linear extension rate and skeletal density were unrelated to isotopic compositions. The fact that skeletal δ18O and δ13C of zooxanthellate corals were confined to a narrower range at the most isotopically depleted end compared to non-zooxanthellate corals, suggests that the photosynthetic activity may restrict corals to a limited range of isotopic composition, away from isotopic equilibrium for both isotopes. Our data show that individual corals within the same species express the full range of isotope fractionation. These results suggest that metabolic and/or kinetic effects may act as controlling factors of isotope variability of skeleton composition along the transect, and that precipitation of coral skeletal aragonite occurs under controlling kinetic biological processes, rather than thermodynamic control, by yet unidentified mechanisms.

New Insights into the Chemical and Isotopic Composition of Human-Body Biominerals. II: COM Kidney Stones from Greece

New Insights into the Chemical and Isotopic Composition of Human-Body Biominerals. II: COM Kidney Stones from Greece

Identification, distribution, and quantification of biominerals in a deciduous forest.

Biomineralization is a common process in most vascular plants, but poorly investigated for trees. Although the presence of calcium oxalate and silica accumulation has been reported for some tree species, the chemical composition, abundance, and quantification of biominerals remain poorly documented. However, biominerals may play important physiological and structural roles in trees, especially in forest ecosystems, which are characterized by nutrient-poor soils. In this context, our study aimed at investigating the morphology, distribution, and relative abundance of biominerals in the different vegetative compartments (foliage, branch, trunk, and root) of Fagus sylvatica L. and Acer pseudoplatanus L. using a combination of scanning electron microscopy and tomography analyses. Biomineral crystallochemistry was assessed by X-ray diffraction and energy-dispersive X-ray analyses, while calcium, silicon, and oxalic acid were quantified in the compartments and at the forest scale. Our analyses revealed that biominerals occurred as crystals or coating layers mostly in bark and leaves and were identified as opal, whewellite, and complex biominerals. In both tree species, opal was mostly found in the external tissues of trunk, branch, and leaves, but also in the roots of beech. In the stand, opal represents around 170kg/ha. Whewellite was found to suit to conductive tissues (i.e., axial phloem parenchyma, vascular bundles, vessel element) in all investigated compartments of the two tree species. The shape of whewellite was prismatic and druses in beech, and almost all described shapes were seen in sycamore maple. Notably, the amount of whewellite was strongly correlated with the total calcium in all investigated compartments whatever the tree species is, suggesting a biologic control of whewellite precipitation. The amount of whewellite in the aboveground biomass of Montiers forest was more important than that of opal and was around 1170 kg/ha. Therefore, biominerals contribute in a substantial way to the biogeochemical cycles of silicon and calcium.

Analytical geochemistry in the service of medicine: An experimental study of urinary stones from Northern Greece

Knowledge of the precise human biomineral composition may allow physicians to recommend an appropriate prophylactic therapy for the patient and thus prevent or delay the stone recurrence. The present study focuses on the application of complementary analytical techniques to the characterization of human urinary stones. Several gallbladder and renal stone samples were obtained from patients dwelling in areas of northern Greece. A comprehensive analytical study took place, employing the following, common in analytical geochemistry, techniques: Environmental Scanning Electron Microscopy (ESEM) coupled to Energy Dispersive System (EDS), X-Ray Diffraction (XRD), thermogravimetry (TG), μRaman spectroscopy and Cathodoluminescence (CL). A detailed determination of morphological, micro-structural, molecular, chemical and mineralogical characteristics of the urinary stone samples was achieved. It was evident by our study the application of powerful analytical techniques could substantially help the medical advisors to ascribe a medical treatment of diseases related to stone formation.

Nacre tablet thickness records formation temperature in modern and fossil shells

Nacre, the iridescent outer lining of pearls and inner lining of many mollusk shells, is composed of periodic, parallel, organic sheets alternating with aragonite (CaCO3) tablet layers. Nacre tablet thickness (TT) generates both nacre's iridescence and its remarkable resistance to fracture. Despite extensive studies on how nacre forms, the mechanisms controlling TT remain unknown, even though they determine the most conspicuous of nacre's characteristics, visible even to the naked eye.Thermodynamics predicts that temperature (T) will affect both physical and chemical components of biomineralized skeletons. The chemical composition of biominerals is well-established to record environmental parameters, and has therefore been extensively used in paleoclimate studies. The physical structure, however, has been hypothesized but never directly demonstrated to depend on the environment. Here we observe that the physical TT in nacre from modern and fossil shallow-water shells of the bivalves Pinna and Atrina correlates with T as measured by the carbonate clumped isotope thermometer. Based on the observed TT vs. T correlation, we anticipate that TT will be used as a paleothermometer, useful to estimate paleotemperature in shallow-water paleoenvironments. Here we successfully test the proposed new nacre TT thermometer on two Jurassic Pinna shells. The increase of TT with T is consistent with greater aragonite growth rate at higher T, and with greater metabolic rate at higher T. Thus, it reveals a complex, T-dependent biophysical mechanism for nacre formation.

Molecular structure and morphology of biomineral composites based on nanohydroxyapatite and hyaluronic acid

New biocomposites based on hydroxyapatite and hyaluronic acid are obtained, and their structural and morphological characteristics are studied. With the use of a set of physicochemical methods, the effect of hyaluronic acid as an active medium in the synthesis of hydroxyapatite used to produce synthetic biocomposites close in structure to native hydroxyapatite is investigated.