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1.
Methods Mol Biol ; 2273: 85-102, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33604846

RESUMO

Cells have a remarkable ability to self-organize and rearrange in functional organoids, this process was greatly boosted by the recent advances in 3D culture technologies and materials. Presently, this approach can be applied to model human organ development and function "in a dish" and can be used to predict drug response in a patient specific fashion.Here we describe a protocol that allows for the derivation of functional cardiac mini organoids consisting of cocultured cardiomyocytes and cardiac fibroblast. Cells are suspended in a drop of medium and encapsulated with hydrophobic fumed silica powder nanoparticles. These nanoparticles are treated with hydrophobic chemicals, hexamethyldisilazane (nHMDS), and result in the formation of microbioreactors. These microenvironments are defined as "liquid marbles," stimulating cell coalescence and 3D aggregation. Then nHMDS shell ensures optimal gas exchange between the interior liquid and the surrounding environment. This microbioreactor makes working in smaller volumes possible and is therefore amenable for higher throughput applications. Moreover, the properties of liquid marble microbioreactors makes it an excellent culture technique for cocultures. Here we demonstrate how cocultures of cardiac fibroblast and cardiomyocytes in a cardiosphere can be a valuable tool to model cardiac diseases in vitro and to assess cell interactions to decipher disease mechanisms.


Assuntos
Técnicas de Cultura de Células/métodos , Miócitos Cardíacos/metabolismo , Organoides/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Carbonato de Cálcio/química , Comunicação Celular/fisiologia , Sobrevivência Celular , Fibroblastos/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Dióxido de Silício/química , Esferoides Celulares
2.
Food Chem ; 348: 128740, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33493844

RESUMO

The bioaccessibility and bioavailability of a functionalized Calcium (Ca) salt as food ingredient, based on modified Ca carbonate and hydroxyapatite (FCC), was determined and compared with frequently used Ca sources (Ca citrate tetrahydrate (CCT), tri-Ca phosphate (triCP) and Ca carbonate (CC). Results showed a similar Ca bioaccessibility for CCT (76.44 ± 9.73%), CC (73.7 ± 8.18%) and FCC (74.4 ± 1.87%) and a lower value for tri-CP (46.07 ± 8.68%). FCC showed the highest bioavailability, 5.68 ± 0.26%, compared to CC, CCT and tri-CP (3.93 ± 0.99%, 3.41 ± 0.33%, 1.85 ± 0.34%, respectively). The innovative chemical composition and structure of FCC based on amorphous hydroxyapatite combined with Ca carbonate, a greater porosity, lower agglomerates and particle size, improve the Ca solubility in the intestinal media, explaining the similar bioaccessibility but higher bioavailability of FCC compared to CCT, tri-CP and CC.


Assuntos
Carbonato de Cálcio/química , Carbonato de Cálcio/farmacocinética , Ingredientes de Alimentos/análise , Disponibilidade Biológica , Fosfatos de Cálcio/química , Porosidade , Solubilidade
3.
ACS Appl Mater Interfaces ; 13(2): 3259-3269, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33410679

RESUMO

The polymer layer-by-layer assembly is accounted among the most attractive approaches for the design of advanced drug delivery platforms and biomimetic materials in 2D and 3D. The multilayer capsules can be made of synthetic or biologically relevant (e.g., natural) polymers. The biopolymers are advantageous for bioapplications; however, the design of such "biocapsules" is more challengeable due to intrinsic complexity and lability of biopolymers. Until now, there are no systematic studies that report the formation mechanism for multilayer biocapsules templated upon CaCO3 crystals. This work evaluates the structure-property relationship for 16 types of capsules made of different biopolymers and proposes the capsule formation mechanism. The capsules have been fabricated upon mesoporous cores of vaterite CaCO3, which served as a sacrificial template. Stable capsules of polycations poly-l-lysine or protamine and four different polyanions were successfully formed. However, capsules made using the polycation collagen and dextran amine underwent dissolution. Formation of the capsules has been correlated with the stability of the respective polyelectrolyte complexes at increased ionic strength. All formed capsules shrink upon core dissolution and the degree of shrinkage increased in the series of polyanions: heparin sulfate < dextran sulfate < chondroitin sulfate < hyaluronic acid. The same trend is observed for capsule adhesiveness to the glass surface, which correlates with the decrease in polymer charge density. The biopolymer length and charge density govern the capsule stability and internal structure; all formed biocapsules are of a matrix-type, other words are microgels. These findings can be translated to other biopolymers to predict biocapsule properties.


Assuntos
Carbonato de Cálcio/química , Polímeros/química , Cápsulas , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Polieletrólitos/química , Porosidade
4.
Food Chem ; 338: 127842, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32822902

RESUMO

Cadmium, inorganic arsenic and, potentially, dimethyl arsenic acid are carcinogens widely elevated in rice. Here it was identified that the food-safe and common cadmium chelator citric acid efficiently removed cadmium from intact grain via pre-soaking procedure, while also reducing arsenic species. A twostep pre-soaking stage was developed whereby rice was first incubated, at ambient temperature, in 1 M citric acid for 12 h, and then in 1 M calcium carbonate for another 12 h, the latter step to neutralize pH, followed by cooking. When 10 different individual types of rice were processed in such a way this resulted in removal rates of 79% for cadmium, 81% for inorganic arsenic and a 66% for DMA. The technology is particularly suitable for bulk food processing and could be deployed in the most cadmium and arsenic impacted regions where rice is a staple.


Assuntos
Arsenicais/química , Ácido Cacodílico/química , Cádmio/química , Contaminação de Alimentos/análise , Oryza/química , Arsenicais/análise , Ácido Cacodílico/análise , Cádmio/análise , Carbonato de Cálcio/química , Ácido Cítrico/química , Culinária/métodos , Concentração de Íons de Hidrogênio , Espectrometria de Massas/métodos , Oryza/metabolismo
5.
Ecotoxicol Environ Saf ; 207: 111512, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254392

RESUMO

This study investigated 324 groundwater samples collected from the southwest plain of Shandong Province during the dry and wet seasons. Groundwater fluoride in the study area and the influencing factors were characterized and discussed using statistical analysis, ion ratios, Piper diagrams, the saturation index (SI) and ArcGIS software. In addition, the risk posed by groundwater fluoride to human health was assessed. The results showed that groundwater in the study area had elevated fluoride concentrations, with average dry and wet season concentrations of 1.15 mg·L-1 and 1.08 mg·L-1, respectively. Groundwater fluoride showed consistent spatial variations during the dry and wet seasons, with a significant regionalization pattern of low concentrations in the east and high concentrations in the west. Groundwater F- was significantly negatively correlated with Ca2+ and positively correlated with pH, HCO3- and Na+. Important factors identified as having an effect on groundwater F- in the study area included the balance of dissolution of fluorite and calcite, the weakly alkaline environment and cation exchange. In addition, hydrochemical types of high-fluoride groundwater in the study area were identified as mainly HCO3-Na and SO4·Cl-Na. The assessment of the risk of high groundwater fluoride to human health showed that children are more at risk compared to adults, with the risk during the dry season exceeding that over the wet season. It is recommended that water quality management in the study area prioritize the formulation of measures to mitigate high concentrations of fluoride in groundwater .


Assuntos
Monitoramento Ambiental , Fluoretos/análise , Poluentes Químicos da Água/análise , Adulto , Carbonato de Cálcio/química , Criança , China , Água Subterrânea/química , Saúde , Humanos , Minerais/análise , Sódio/análise , Qualidade da Água
6.
Chemosphere ; 262: 128357, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182098

RESUMO

The cost-effective recovery of phosphate is of great significance to the mitigation of phosphorus resource depletion crisis. The electrochemical-decomposition of dolomite was developed to recover phosphate and ammonium from aqueous solution. The dolomite ore is mainly composed of CaMg(CO3)2 (53.73%), CaCO3 (28.93%) and SiO2 (16.59%). The continuous release of Mg2+ and Ca2+ were achieved by electrochemically decomposing dolomite ore, accompanied by the generation of base solution (9.0-10.5). The main factors affecting the recovery performance of phosphate (PO4-P) and ammonium (NH4-N) are current, initial concentration of PO4-P and NH4-N, initial pH of feed solution and feed rate. For a 30-d operation, the recovery rate of PO4-P was maintained at 90-97% and that of NH4-N at 50-60% under optimized operating conditions. The recovered product had low water solubility but high citric-acid-soluble, and was proposed as a slow-release fertilizer for crops. The proposed process as a simple, effective and green route may serve as a new strategy for recovering PO4-P and NH4-N from wastewaters.


Assuntos
Compostos de Amônio/química , Carbonato de Cálcio/química , Técnicas Eletroquímicas/métodos , Magnésio/química , Fosfatos/química , Eliminação de Resíduos Líquidos/métodos , Compostos de Amônio/isolamento & purificação , Cálcio/química , Eletrodos , Fertilizantes , Concentração de Íons de Hidrogênio , Fosfatos/isolamento & purificação , Fósforo/química , Dióxido de Silício , Soluções , Águas Residuárias/química , Poluentes Químicos da Água/química
7.
Molecules ; 26(1)2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33379374

RESUMO

Polyurethanes have the potential to impart cell-relevant properties like excellent biocompatibility, high and interconnecting porosity and controlled degradability into biomaterials in a relatively simple way. In this context, a biodegradable composite material made of an isocyanate-terminated co-oligoester prepolymer and precipitated calcium carbonated spherulites (up to 60% w/w) was synthesized and investigated with regard to an application as bone substitute in dental and orthodontic application. After foaming the composite material, a predominantly interconnecting porous structure is obtained, which can be easily machined. The compressive strength of the foamed composites increases with raising calcium carbonate content and decreasing calcium carbonate particle size. When stored in an aqueous medium, there is a decrease in pressure stability of the composite, but this decrease is smaller the higher the proportion of the calcium carbonate component is. In vitro cytocompatibility studies of the foamed composites on MC3T3-E1 pre-osteoblasts revealed an excellent cytocompatibility. The in vitro degradation behaviour of foamed composite is characterised by a continuous loss of mass, which is slower with higher calcium carbonate contents. In a first pre-clinical pilot trial the foamed composite bone substitute material (fcm) was successfully evaluated in a model of vertical augmentation in an established animal model on the calvaria and on the lateral mandible of pigs.


Assuntos
Materiais Biocompatíveis/administração & dosagem , Desenvolvimento Ósseo/efeitos dos fármacos , Carbonato de Cálcio/administração & dosagem , Poliésteres/administração & dosagem , Poliuretanos/administração & dosagem , Células 3T3 , Animais , Materiais Biocompatíveis/química , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/administração & dosagem , Substitutos Ósseos/química , Carbonato de Cálcio/química , Linhagem Celular , Força Compressiva/efeitos dos fármacos , Feminino , Camundongos , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Projetos Piloto , Poliésteres/química , Poliuretanos/química , Porosidade , Suínos , Tecidos Suporte/química
8.
Chemosphere ; 254: 126903, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957296

RESUMO

We used discarded oyster shells to prepare vaterite calcium carbonate microparticles and explored the removal effects and the underlying mechanism toward several heavy metal ions. The removal efficiency for each ion type was: Pb2+ (99.9%), Cr3+ (99.5%), Fe3+ (99.3%), and Cu2+ (57.1%). With the exception of Cu2+, vaterite calcium carbonate particles exhibited excellent removal performance on all tested heavy metal ions, with exceptional results for Pb2+. The factor affecting the removal efficiency of heavy metal ions is shown to involve an ion exchange reaction between calcium and the heavy metal ions resulting in recrystallization. Vaterite calcium carbonate particles prepared by this method have the advantage of low price, easy synthesis, and reduction of environmental waste. Thus, this procedure for synthesizing vaterite CaCO3 provides an environmentally responsible method for preparing materials that can be economically incorporated into common consumer products such as household drinking water filtration systems.


Assuntos
Exoesqueleto/química , Carbonato de Cálcio/química , Metais Pesados/análise , Ostreidae , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Animais , Concentração de Íons de Hidrogênio , Troca Iônica , Íons , Microesferas , Propriedades de Superfície
9.
PLoS One ; 15(9): e0238432, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881918

RESUMO

The carbonate system in two contrasting fjords, Rivers Inlet and Bute Inlet, on the coast of British Columbia, Canada, was evaluated to characterize the mechanisms driving carbonate chemistry dynamics and assess the impact of anthropogenic carbon. Differences in the character of deep water exchange between these fjords were inferred from their degree of exposure to continental shelf water and their salinity relationships with total alkalinity and total dissolved inorganic carbon, which determined seawater buffering capacity. Seawater buffering capacity differed between fjords and resulted in distinct carbonate system characteristics with implications on calcium carbonate saturation states and sensitivity to increasing anthropogenic carbon inputs. Saturation states of both aragonite and calcite mineral phases of calcium carbonate were seasonally at or below saturation throughout the entire water column in Bute Inlet, while only aragonite was seasonally under-saturated in portions of the water column in Rivers Inlet. The mean annual saturation states of aragonite in Rivers Inlet and calcite in Bute Inlet deep water layers have declined to below saturation within the last several decades due to anthropogenic carbon accumulation, and similar declines to undersaturation are projected in their surface layers as anthropogenic carbon continues to accumulate. This study demonstrates that the degree of fjord water exposure to open shelf water influences the uptake and sensitivity to anthropogenic carbon through processes affecting seawater buffering capacity, and that reduced uptake but greater sensitivity occurs where distance to ocean source waters and freshwater dilution are greater.


Assuntos
Carbonatos/análise , Monitoramento Ambiental/métodos , Água do Mar/química , Colúmbia Britânica , Carbonato de Cálcio/química , Carbono/química , Dióxido de Carbono/análise , Ecossistema , Estuários , Concentração de Íons de Hidrogênio , Salinidade , Água do Mar/análise
10.
Ars pharm ; 61(3): 163-168, jul.-sept. 2020. tab, ilus, graf
Artigo em Inglês | IBECS | ID: ibc-195118

RESUMO

INTRODUCTION: The aim of the present study was to develop and to characterize the floating raft system (FRS) of Amoxicillin to enhance gastric residence time and drug release to target Helicobacter pylori effectively. METHOD: In the present study, guar gum, glyceryl monostearate (GMS), calcium carbonate were selected as factors. Gelation duration (h), floating lag time (min), and % Cumulative drug release (CDR) were selected as responses. 23 factorial design with replicates was selected for experimentation. RESULTS: It was observed that guar gum and GMS were the major factors affecting gelation duration, increase in the quantity of both guar gum and GMS increased gelation duration i.e., sustained gelation period (24 h). Floating time increased with an increase in the amount of guar gum and calcium carbonate, whereas an increase in the quantity of GMS decreased floating time. Guar gum, calcium carbonate, and GMS exhibited an antagonistic effect on % CDR. Contour plots were used to identify design space; further numerical analysis yielded 12 best solutions based on desirability. FRS exhibited greater AUCo-t, Cmax, tmax, and t1/2 when compared to marketed formulation approximately 2.30 folds enhancement and prolongation with a sustained release for greater than 24 h that might be due to better gelation CONCLUSIONS: It can be concluded that the floating raft system was successfully developed by the Design of experiment (DoE) application with fewer trails and by utilizing easily available excipients for better floating, gelation, and sustained delivery of the drug


INTRODUCCIÓN: El objetivo del presente estudio fue formular y caracterizar el Sistema Flotante (FRS, siglas en Inglés) de Amoxicilina para prolongar el tiempo de residencia gástrica y liberación del fármaco para el enfoque efectivo del Helicobacter pylori. MÉTODO: Para el presente estudio se seleccionaron como factores goma guar, Monoestearato de glicerilo (GMS), carbonato de calcio. Como reacciones, se seleccionaros el período de congelación (h), el lapso de flotación (min), y el porcentaje acumulado de liberación del fármaco (CDR). Para la experimentación se seleccionaron el diseño factorial 23 con réplicas. RESULTADOS: Se observó que la goma guar y el GMS fueron los factores principales que afectaron el período de congelación y mostraron un efecto sinérgico (positivo). Mientras que la goma guar y el carbonato de calcio mostraron un efecto positivo y el GMS mostró un efecto antagónico (negativo) en el lapso de flotación. El porcentaje CDR mostró un efecto antagónico en todos los factores. Se emplearon curvas de nivel para identificar el diseño del espacio, análisis numéricos posteriores produjeron 12 soluciones óptimas en base a la deseabilidad. El FRS mostró un mayor AUCo-t, Cmax, tmaxy t1/2 cuando se comparó con la formulación comercial, aproximadamente 2.30 cambios múltiplos y prolongación con liberación sostenida por más de 24 h que pudo deberse a una mejor congelación. CONCLUSIONES: Se puede concluir que el sistema flotante se desarrolló satisfactoriamente por la aplicación del Diseño de Experimentos (DoE) con menores ensayos y utilizando fácilmente los excipientes disponibles para una mejor flotación, congelación y suministro constante del fármaco


Assuntos
Composição de Medicamentos/métodos , Amoxicilina/química , Infecções por Helicobacter/tratamento farmacológico , Liberação Controlada de Fármacos , Técnicas In Vitro , Helicobacter pylori/efeitos dos fármacos , Amoxicilina/farmacologia , Congelamento , Cyamopsis/química , Carbonato de Cálcio/química , Análise de Variância , Antibacterianos/farmacocinética , Amoxicilina/farmacocinética
11.
PLoS One ; 15(8): e0236745, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785276

RESUMO

Mineral precipitation via microbial activity is a well-known process with applications in various fields. This relevance of microbially induced calcite precipitation (MICP) has pushed researchers to explore various naturally occurring MICP capable bacterial strains. The present study was performed to explore the efficiency of microbially induced calcite precipitation (MICP) via locally isolated bacterial strains and role of guar gum, which is a naturally occurring polymer, on the MICP process. The strains were isolated from local soil and screened for urease activity Further, the urease positive strain was subjected to urea and calcium chloride based medium to investigate the efficacy of isolated strain for microbial induced precipitation. Among screened isolates, the soil bacterium that showed urease positive behaviour and precipitated calcium carbonate was subjected to 16S rRNA gene sequencing. This strain was identified as Bacillus velezensis. Guar gum-a natural polymer, was used as a sole carbon source to enhance the MICP process. It was observed that the isolated strain was able to breakdown the guar gum into simple sugars resulting in two-fold increase in calcium carbonate precipitate. Major bio-chemical activities of isolated strain pertaining to MICP such as ammonium ion concentration, pH profiling, and total reducing sugar with time were explored under four different concentrations of guar gum (0.25%, 0.5%, 0.75% and 1% w/v). Maximum ammonium ion concentration (17.5 µg/ml) and increased pH was observed with 1% guar gum supplementation, which confirms augmented MICP activity of the bacterial strain. Microstructural analysis of microbial precipitation was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, which confirmed the presence of calcium carbonate in different phases. Further, XRD and SEM based studies corroborated that guar gum supplemented media showed significant increase in stable calcite phase as compared to media without guar gum supplementation. Significant diverse group of nitrogenous compounds were observed in guar gum supplemented medium when subjected to Gas Chromatography-Mass spectrometry (GC-MS) profiling.


Assuntos
Bacillus/metabolismo , Carbonato de Cálcio/química , Carbonato de Cálcio/metabolismo , Galactanos/química , Mananas/química , Gomas Vegetais/química , Precipitação Química
12.
Int J Nanomedicine ; 15: 4049-4062, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606663

RESUMO

Background: Calcium carbonate (CC) nanoparticles have broad biomedical utilizations, owing to their multiple intrinsic merits. However, bare CC nanoparticles do not allow for the development of multifunctional devices suitable for advanced drug delivery in cancer therapy. Methods: Phospholipid-modified phospholipid-CC hybrid nanoparticles were prepared in our study using a combination of vapor-diffusion and solvent-diffusion methods to offer optimized pharmaceutical capabilities. Results: Considering that particle size is a critical parameter that plays an important role in both in vitro and in vivo behaviors of nanoparticles, we here for the first time a present detailed protocol for the size-controlled preparation of hybrid nanoparticles, as well as analysis of the in vitro/in vivo behaviors of differently sized hybrid nanoparticles. Conclusion: Our results might significantly advance the application of this promising material in more varied fields.


Assuntos
Carbonato de Cálcio/química , Nanopartículas/química , Tamanho da Partícula , Fosfolipídeos/química , Animais , Linhagem Celular , Permeabilidade da Membrana Celular , Sistemas de Liberação de Medicamentos/métodos , Endocitose , Feminino , Humanos , Lisossomos/metabolismo , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Nanopartículas/ultraestrutura , Coelhos , Esferoides Celulares/metabolismo , Eletricidade Estática , Temperatura , Fatores de Tempo , Distribuição Tecidual
13.
Chemosphere ; 260: 127527, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673868

RESUMO

Desalination of brackish water is energetically attractive, but the concentrate produced poses a major environmental issue. Intensive research has been carried out to develop demineralization techniques of such concentrates to facilitate their utilization and disposal. Aeration was reported to allow chemical-free and effective demineralization through CaCO3 precipitation. When applied in concentrate treatment, the process was assumed to follow first order kinetics, but second order kinetics were proposed when the process was applied in potable groundwater treatment. In the current study the effect of aeration rates and seed concentration on reaction kinetics was studied in real brackish water desalination concentrates (BWDC). In the absence of or at low aeration, CaCO3(s) precipitation followed second order kinetics characteristic of simple CaCO3(s) precipitation. With increasing aeration rate, the reaction shifted toward first order kinetics, characteristic of gaseous CO2 release. Both aeration rate and seed concentration linearly increased the gas mass transfer coefficient. Under the experimental conditions, maximal removal rate was 1.05 g calcium-CaCO3 L-1 h-1. Calcium removal reached 73% and was found to depend on raw concentrate composition and reaction time. The composition of the softened concentrate corresponded well with the geochemical PHREEQC code simulation of the solution at equilibrium. The precipitates comprised at least 92% calcite, which may be of economic significance. The ability to use the intrinsic precipitates as seed particles may be advantageous in terms of CaCO3 recovery and simplicity of operation.


Assuntos
Purificação da Água/métodos , Carbonato de Cálcio/química , Água Subterrânea/química , Cinética , Águas Salinas
14.
Nature ; 583(7816): 406-410, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32555457

RESUMO

Calcified eggshells protect developing embryos against environmental stress and contribute to reproductive success1. As modern crocodilians and birds lay hard-shelled eggs, this eggshell type has been inferred for non-avian dinosaurs. Known dinosaur eggshells are characterized by an innermost membrane, an overlying protein matrix containing calcite, and an outermost waxy cuticle2-7. The calcitic eggshell consists of one or more ultrastructural layers that differ markedly among the three major dinosaur clades, as do the configurations of respiratory pores. So far, only hadrosaurid, a few sauropodomorph and tetanuran eggshells have been discovered; the paucity of the fossil record and the lack of intermediate eggshell types challenge efforts to homologize eggshell structures across all dinosaurs8-18. Here we present mineralogical, organochemical and ultrastructural evidence for an originally non-biomineralized, soft-shelled nature of exceptionally preserved ornithischian Protoceratops and basal sauropodomorph Mussaurus eggs. Statistical evaluation of in situ Raman spectra obtained for a representative set of hard- and soft-shelled, fossil and extant diapsid eggshells clusters the originally organic but secondarily phosphatized Protoceratops and the organic Mussaurus eggshells with soft, non-biomineralized eggshells. Histology corroborates the organic composition of these soft-shelled dinosaur eggs, revealing a stratified arrangement resembling turtle soft eggshell. Through an ancestral-state reconstruction of composition and ultrastructure, we compare eggshells from Protoceratops and Mussaurus with those from other diapsids, revealing that the first dinosaur egg was soft-shelled. The calcified, hard-shelled dinosaur egg evolved independently at least three times throughout the Mesozoic era, explaining the bias towards eggshells of derived dinosaurs in the fossil record.


Assuntos
Dinossauros , Casca de Ovo/anatomia & histologia , Casca de Ovo/química , Fósseis , Dureza , Animais , Evolução Biológica , Biomineralização , Carbonato de Cálcio/análise , Carbonato de Cálcio/química
15.
Ultrasonics ; 108: 106198, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32590261

RESUMO

Contrast-enhanced ultrasound (CEUS) is widely applied in cancer diagnosis clinically. However, the gas-filled contrast agents are unstable in the blood and exhibit shorter imaging time, which limit their clinical use. In this study, a diagnostic nanoparticle system was developed for dual-mode imaging (ultrasound and fluorescence), which after encapsulation with doxorubicin (DOX) demonstrated simultaneous therapeutic function towards cancer treatment. Thus, calcium carbonate (CaCO3) nanoparticles were encapsulated with doxorubicin (DOX) to obtain CaCO3-DOX. Under acidic conditions, it produced carbon dioxide (CO2) to enhance ultrasound imaging and increase the release of DOX. After intravenously injecting CaCO3-DOX to tumor-bearing mice, in the presence of an ultrasound field, CO2bubbles were sufficiently generated at the tumor tissues for echogenic reflectivity. Also, the indocyanine green (ICG) was encapsulated into CaCO3 nanoparticles, to further detect the tumor with fluorescence. The resultant theranostic nanoparticle system exhibited therapeutic efficacy towards tumour-bearing mice. Overall, this investigation provides an attractive strategy for dual-mode cancer diagnostics.


Assuntos
Carbonato de Cálcio/farmacologia , Doxorrubicina/farmacologia , Imagem Multimodal , Neoplasias Experimentais/diagnóstico por imagem , Neoplasias Experimentais/tratamento farmacológico , Nanomedicina Teranóstica/métodos , Ultrassonografia/métodos , Animais , Carbonato de Cálcio/química , Dióxido de Carbono/metabolismo , Linhagem Celular Tumoral , Meios de Contraste , Doxorrubicina/química , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Fluorescência , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Microambiente Tumoral
16.
Chemosphere ; 255: 127005, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416395

RESUMO

Recovering phosphorus from livestock wastewater could partly mitigate the global phosphorus resource crisis. Crystallization is a promising method for removing phosphorus from wastewater, but the costs of calcium- and magnesium-containing reagents are increasing. Cheap, available, efficient materials are required to replace conventional calcium and magnesium reagents. Here, we describe a new approach to removing and recovering phosphorus from livestock wastewater of a large pig farm, containing a high phosphorus concentration. The effects of the pH, stirring speed, stirring time, and extract dose (containing calcium and magnesium) on phosphorus removal from livestock wastewater were investigated. The product was characterized by X-ray diffractometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Under optimized conditions (pH 9.0, stirring speed 200 r/m, stirring time 600 s, Ca 207.62 mg/L, Mg 122.86 mg/L), 92% of the phosphorus was removed from livestock wastewater. The product was mainly the hydroxyapatite (Ca5(PO4)3OH) precursor amorphous calcium phosphate but also contained 1.65% (by mass) magnesium ammonium phosphate (MgNH4PO4·6H2O) crystals. The cost of dolomite to treat 1 m3 of high-phosphorus wastewater was 0.20 yuan (45.9%, 25.9%, and 75.9% lower than for pure MgCl2, MgSO4, and CaCl2, respectively) in 2019. Using dolomite to provide calcium and magnesium effectively decreases the crystallization process cost and should encourage the use of crystallization to remove phosphorus from wastewater.


Assuntos
Carbonato de Cálcio/química , Magnésio/química , Fósforo/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Animais , Fosfatos de Cálcio/isolamento & purificação , Cristalização , Fazendas , Gado/crescimento & desenvolvimento , Estruvita/isolamento & purificação , Suínos
17.
Sci Rep ; 10(1): 8696, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32457467

RESUMO

Amorphous calcium carbonate (ACC) is a precursor of crystalline calcium carbonates that plays a key role in biomineralization and polymorph evolution. Here, we show that several bacterial strains isolated from a Hungarian cave produce ACC and their extracellular polymeric substance (EPS) shields ACC from crystallization. The findings demonstrate that bacteria-produced ACC forms in water-rich environment at room temperature and is stable for at least half year, which is in contrast to laboratory-produced ACC that needs to be stored in a desiccator and kept below 10 °C for avoiding crystallization. The ACC-shielding EPS consists of lipids, proteins, carbohydrates and nucleic acids. In particular, we identified large amount of long-chain fatty acid components. We suggest that ACC could be enclosed in a micella-like formula within the EPS that inhibits water infiltration. As the bacterial cells lyse, the covering protective layer disintegrates, water penetrates and the unprotected ACC grains crystallize to calcite. Our study indicates that bacteria are capable of producing ACC, and we estimate its quantity in comparison to calcite presumably varies up to 20% depending on the age of the colony. Since diverse bacterial communities colonize the surface of cave sediments in temperate zone, we presume that ACC is common in these caves and its occurrence is directly linked to bacterial activity and influences the geochemical signals recorded in speleothems.


Assuntos
Bactérias/metabolismo , Carbonato de Cálcio/metabolismo , Bacillus/metabolismo , Bactérias/classificação , Bactérias/genética , Carbonato de Cálcio/química , Cristalização , Microscopia Eletrônica de Varredura , Filogenia , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Stenotrophomonas maltophilia/metabolismo , Temperatura , Água/química
18.
Phys Chem Chem Phys ; 22(17): 9713-9722, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32329476

RESUMO

The fast development of protein therapeutics has resulted in a high demand for advanced delivery carriers that can effectively host therapeutic proteins, preserve their bioactivity and release them on demand. Accordingly, vaterite CaCO3 crystals have attracted special attention as sacrificial templates for protein encapsulation in micro- and nanoparticles (capsules and beads, respectively) under mild biofriendly conditions. This study aimed to better understand the mechanism of protein loading into crystals as a primary step for protein encapsulation. The loading of three therapeutic proteins (250 kDa catalase, 5.8 kDa insulin, and 6.5 kDa aprotinin) was investigated for crystals with different porosities. However, unexpectedly, the protein loading capacity was not consistent with the protein molecular weight. It solely depends on the inter-protein interactions in the bulk solution in the presence of crystals and that inside the crystals. The smallest protein aprotinin aggregates in the bulk (its aggregate size is about 100 nm), which prohibits its loading into the crystals. Insulin forms hexamers in the bulk, which can diffuse into the crystal pores but tend to aggregate inside the pores, suppressing protein diffusion inward. Catalase, the largest protein tested, does not form any aggregates in the bulk and diffuses freely into the crystals; however, its diffusion into small pores is sterically restricted. These findings are essential for the encapsulation of protein therapeutics by means of templating based on CaCO3 crystals and for the engineering of protein-containing microparticles having desired architectures.


Assuntos
Carbonato de Cálcio/química , Sistemas de Liberação de Medicamentos , Proteínas/química , Proteínas/metabolismo , Peso Molecular , Porosidade , Ligação Proteica
19.
Phys Chem Chem Phys ; 22(18): 10056-10062, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32338264

RESUMO

The brittlestar Ophiocoma wendtii is theorised to employ a technique already used in metallurgy in order to optimise the mechanical properties of calcitic microlenses within their skeletons. These microlenses contain arrays of Mg-rich nanoprecipitates, which are proposed to inhibit crack propagation through the compression of the local host lattice. Here, we employ classical molecular dynamics in order to study the effects of Mg-rich nanoprecipitates on lattice strain, stress distributions and crack propagation in calcite. Our quantitative results on lattice strain and stress induced on the host matrix are compatible with empirical estimates. Simulations of crack propagation demonstrate that the inclusion of a Mg-rich region results in an increase in stress required to fracture the crystal, as well as higher residual stress in the fractured crystal. This is the result of an inhomogeneous stress distribution causing a more disordered fracture, as well as deflections of the crack away from the lowest energy (10.4) surface. The results agree with the proposal that the compression of the host lattice inhibits propagation, and offer insight into other mechanisms through which the nanoprecipitates affect crack propagation.


Assuntos
Carbonato de Cálcio/química , Magnésio/química , Nanoestruturas/química , Estrelas-do-Mar/química , Estresse Mecânico , Animais , Simulação de Dinâmica Molecular
20.
PLoS One ; 15(4): e0231414, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267882

RESUMO

Mollusc shells are produced from calcified skeletons and have excellent mechanical properties. Shell matrix proteins (SMPs) have important functions in shell formation. A 16.6 kDa whirlin-like protein (WLP) with a PDZ domain was identified in the shell of Mytilus coruscus as a novel SMP. In this study, the expression, function, and location of WLP were analysed. The WLP gene was highly expressed and specifically located in the adductor muscle and mantle. The expression of recombinant WLP (rWLP) was associated with morphological change, polymorphic change, binding ability, and crystallization rate inhibition of the calcium carbonate crystals in vitro. In addition, an anti-rWLP antibody was prepared, and the results from immunohistochemistry and immunofluorescence analyses revealed the specific location of the WLP in the mantle, adductor muscle, and myostracum layer of the shell, suggesting multiple functions for WLP in biomineralization, muscle-shell attachment, and muscle attraction. Furthermore, results from a pull-down analysis revealed 10 protein partners of WLP in the shell matrices and a possible network of interacting WLPs in the shell. In addition, in this study, one of the WLP partners, actin, was confirmed to have the ability to bind WLP. These results expand the understanding of the functions of PDZ-domain-containing proteins in biomineralization and provide clues for determining the mechanisms of myostracum formation and muscle-shell attachment.


Assuntos
Proteínas de Membrana/metabolismo , Mytilus/metabolismo , Sequência de Aminoácidos , Exoesqueleto/metabolismo , Exoesqueleto/ultraestrutura , Animais , Biomineralização , Carbonato de Cálcio/química , Carbonato de Cálcio/metabolismo , Imuno-Histoquímica , Hibridização In Situ , Proteínas de Membrana/química , Proteínas de Membrana/genética , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Ligação Proteica , Estrutura Secundária de Proteína , Proteômica , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia
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