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During intervertebral disc (IVD) degeneration, microenvironmental challenges such as decreasing levels of glucose, oxygen, and pH play crucial roles in cell survival and matrix turnover. Antacids, such as Mg(OH) 2 and CaCO 3 , entrapped in microcapsules are capable of neutralizing acidic microenvironments in a controlled fashion and therefore may offer the potential to improve the acidic niche of the degenerated IVD and enhance cell-based regeneration strategies. The objectives of this work were, first, to develop and characterize antacid microcapsules and assess their neutralization capacity in an acidic microenvironment and, second, to combine antacid microcapsules with cellular microcapsules in a hybrid gel system to investigate their neutralization effect as a potential therapeutic in a disc explant model. To achieve this, we screened five different pH- neutralizing agents (Al(OH) 3 , Mg(OH) 2 , CaCO 3 , and HEPES) in terms of their pH neutralization capacities, with Mg(OH) 2 or CaCO 3 being carried forward for further investigation. Antacid-alginate microcapsules were formed at different concentrations using the electrohydrodynamic spraying process and assessed in terms of size, buffering kinetics, cell compatibility, and cytotoxicity. Finally, the combination of cellular microcapsules and antacid capsules was examined in a bovine disc explant model under physiological degenerative conditions. Overall, CaCO 3 was found to be superior in terms of neutralization capacities, release kinetics, and cellular response. Specifically, CaCO 3 elevated the acidic pH to neutral levels and is estimated to be maintained for several weeks based on Ca 2+ release. Using a disc explant model, it was demonstrated that CaCO 3 microcapsules were capable of increasing the local pH within the core of a hybrid cellular gel system. This work highlights the potential of antacid microcapsules to positively alter the challenging acidic microenvironment conditions typically observed in degenerative disc disease, which may be used in conjunction with cell therapies to augment regeneration., (© 2024 The Author(s). Journal of Biomedical Materials Research Part A published by Wiley Periodicals LLC.)

Tumor cell death induced by "cuproptosis" is a novel form of tumor death that differs from apoptosis induced by chemotherapy. It is expected to emerge as a new approach for cancer treatment. In this study, our focus was on exploiting the characteristic of "cuproptosis" which necessitates increased aerobic respiration to induce tumor cell death. To achieve this, we developed a novel drug delivery system using a CaCO 3 @CuO 2 lipid coating (CaCO 3 @CuO 2 @L). This system aimed to comprehensively modulate the tumor microenvironment and trigger "cuproptosis" in hepatocellular carcinoma (HCC) through the interaction between copper ions and peroxides. Experimental results revealed that the CaCO 3 @CuO 2 @L exhibited a distinct watermelon shape, with CuO 2 evenly distributed within the CaCO 3 nanoparticles. The nanoparticles had an average size of approximately 191 nm. In vitro studies demonstrated that the nanoparticles released CuO 2 in a slightly acidic environment while simultaneously elevating pH levels, reducing glutathione (GSH), and increasing oxygen production. Within liver cancer cells, the CaCO 3 @CuO 2 @L effectively regulated the acidity, GSH levels, and oxygen-depleted microenvironment through the "trinity" mechanism, ultimately inducing "cuproptosis" in HCC. Furthermore, in mouse models with transplanted tumors and orthotopic liver cancer tumors, the CaCO 3 @CuO 2 @L significantly suppressed tumor growth. By triggering "cuproptosis" in HCC, this study offers valuable insights for developing a comprehensive treatment approach for HCC. Ultimately, this research may pave the way for the clinical implementation of the drug delivery system based on "cuproptosis" in liver cancer treatment.

Bio-calcium derived from fish frames may offer several advantages for osteoporosis prevention. This study aimed to evaluate the effects of bio-calcium derived from skipjack tuna frames on bone loss in ovariectomized rats. Tuna bio-calcium was prepared through enzymatic hydrolysis, defatting, bleaching, and grinding processes. The bioavailability of calcium was tested using the Caco-2 cell monolayer model, showing that 13% of tuna bio-calcium was absorbed, compared to 10% for calcium carbonate. Rats were divided into the five following groups: (1) OVX, (2) sham-operated, (3), OVX + estrogen-treated (4) OVX + calcium carbonate-treated, and (5) OVX + tuna bio-calcium-treated. All groups were raised for eight weeks. Tuna bio-calcium was able to increase BV/TV by 26% in the femur and 29% in the tibia, compared to 13% and 17% in the OVX group, respectively. Trabecular thickness in the femur upsurged to 360 µm in the tuna group, while a thickness of 290 µm was observed in the control. Additionally, osteoclast numbers were reduced to 5 N.Oc/mm in the femur and 6 N.Oc/mm in the tibia in the tuna group, compared to 35 and 45 N.Oc/mm in the control. Overall, tuna bio-calcium effectively prevented bone loss and can serve as a promising natural alternative for managing osteoporosis.

This study aimed to design sustained released biodegradable calcium carbonate nanoparticles loaded with chlorhexidine (CHX-loaded NPs) and to investigate the early osteogenic differentiation and antimicrobial effects on the important bacteria involved in infections of dental implants. The microemulsion method was used to prepare the calcium carbonate nanoparticles loaded with chlorhexidine. The prepared nanoparticles were characterized using conventional methods. The release pattern determination and the biodegradation test were performed for the prepared nanoparticles. For the early osteogenic differentiation test of the prepared nanoparticles, alkaline phosphatase (ALP) activity was detected in human dental pulp stem cells (HDPSCs). The antimicrobial effects of the nanoparticles were evaluated against Escherichia coli, Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, and Pseudomonas aeruginosa. The sizes of free calcium carbonate nanoparticles and CHX-loaded NPs were 105 ± 1.63 and 118 ± 1.47 nm and their zeta potentials were - 27 and - 36, respectively. A 50% degradation of nanoparticles was achieved after 100 days. These nanoparticles showed a two-stage sustained release pattern in vitro. Microscopic images revealed that the morphology of free calcium carbonate nanoparticles primarily took on a spherical calcite form, while CHX-loaded NPs predominantly exhibited a cauliflower-like vaterite polymorph. The nanoparticles increased the activity of ALP in cells in two weeks significantly (p < 0.05). Antimicrobial and antibiofilm results showed an efficient effect of the prepared nanoparticle against the studied bacteria. Calcium carbonate nanoparticles are an efficient multifunctional vector for chlorhexidine and can be used as a bioactive antibacterial agent against various oral microorganisms to prevent implant infections., (© 2024. The Author(s).)

Unfavorable phenotypes characterized by low immunogenicity and acidity within the tumor microenvironment (TME) contribute to immunosuppression and therapeutic resistance. Herein, we rationally synthesized a multifunctional nanoregulator by encapsulating DOX and erianin into calcium carbonate (CaCO 3 )-based nanoparticles using a modified double emulsion method. The DOX and erianin-loaded CaCO 3 -based nanoparticles, termed DECaNPs, could effectively induce the calcium overload by triggering calcium influx and absorbing CaCO 3 nanoparticles. Additionally, DECaNPs also neutralize the acidic TME by interacting with extracellular protons and limiting lactic acid production, a result of metabolic remodeling in cancer cells. As a result, DECaNPs elicit cellular oxidative stress damage, which mediates the activation of ferroptosis/apoptosis hybrid pathways, and profound immunogenic cell death. Treatment with DECaNPs could inhibit the growth of tumors by promoting oxidative stress, acid neutralization, metabolic remodeling, and protective antitumor immunity in vivo . In addition, DECaNPs could synergistically amplify the antitumor effects of αPD-L1 in a bilateral tumor model by eliciting systemic immune responses. In all, our work presents the preparation of CaCO 3 -based nanoregulators designed to reverse the unfavorable TME and enhance αPD-L1 immunotherapy through multiple mechanisms.

The biomimetic nanoparticles (NPs) possessing abilities of tumor targeting and multimodal therapy show great potential for efficient combat of colon cancer. Herein, we developed a multifunctional biomimetic nanoplatform (Fe 3 O 4 @PDA@CaCO 3 -ICG@CM) based on CaCO 3 -modified magnetic polydopamine (PDA) loaded with indocyanine green (ICG), which was encapsulated by a mouse lymphoma cell (EL4) membrane (CM) expressing functional proteins (i.e., lymphocyte function-associated antigen 1, LFA-1; transforming growth factor-β receptor, TGF-βR; programmed cell death protein 1, PD-1; and factor related apoptosis ligand, FasL). Under magnetic attraction and LFA-1/PD-1-mediated endocytosis, Fe 3 O 4 @PDA@CaCO 3 -ICG@CM efficiently targeted CT26 colon tumor cells. The released calcium ion (Ca 2+ ) from the NPs triggered by acidic tumor microenvironment, the enhanced photothermal effect contributed by the combination of PDA and ICG, and FasL's direct killing effect together induced tumor cells apoptosis. Moreover, the apoptosis of CT26 cells induced immunogenic cell death (ICD) to promote the maturation of dendritic cells (DCs) to activate CD4 + /CD8 + T cells, thereby fighting against tumor cells, which could further be boosted by programmed death-ligand 1 (PD-L1) blockage and transforming growth factor-β (TGF-β) scavenging by Fe 3 O 4 @PDA@CaCO 3 -ICG@CM. As a result, in vivo satisfactory therapeutic effect was observed for CT26 tumor bearing-mice treated with Fe 3 O 4 @PDA@CaCO 3 -ICG@CM under laser irradiation and magnetic attraction, which could eradicate primary tumors and restrain distant tumors through dual tumor targeting-assisted multimodal therapy and eliciting adaptive antitumor immune response, generating the immune memory for inhibiting tumor metastasis and recurrence. Taken together, the multifunctional biomimetic nanoplatform exhibits superior antitumor effects, providing an insightful strategy for the field of nanomaterial-based treatment of cancer.

Strengthening tumor cellular adhesion through regulating the concentration of extracellular Ca 2+ is highly challenging and promising for antimetastasis. Herein, a pH-responsive conjugated polymer-calcium composite nanoparticle (PFV/CaCO 3 /PDA@PEG) is developed for calcium-mediated cell adhesion enhancement-based antimetastasis and reactive oxygen species (ROS)-triggered calcium overload and photodynamic therapy (PDT) synergistic tumor treatment. PFV/CaCO 3 /PDA@PEG is mainly equipped with conjugated poly(fluorene- co -vinylene) (PFV-COOH)-composited CaCO 3 nanoparticles, which can be rapidly decomposed under the tumor acidic microenvironment, effectively releasing Ca 2+ and the photosensitizer PFV-COOH. The high extracellular Ca 2+ concentration facilitates the generation of dimers between two adjacent cadherin ectodomains, which greatly enhances cell-cell adhesion and suppresses tumor metastasis. The inhibition rates are 97 and 87% for highly metastatic tumor cells 4T1 and MCF-7, respectively. Such a well-designed nanoparticle also contributes to realizing PDT, mitochondrial dysfunction, and ROS-triggered Ca 2+ overload synergistic therapy. Furthermore, PFV/CaCO 3 /PDA@PEG displayed superior in vivo inhibition of 4T1 tumor growth and demonstrated a marked antimetastatic effect by both intravenous and intratumoral injection modes. Thus, this study provides a powerful strategy for calcium-mediated metastasis inhibition for tumor therapy.

Osteosarcoma (OS) is a "cold" tumor enriched in noninflammatory M2 phenotype tumor-associated macrophages (TAMs), which limits the efficacy of immunotherapy. The acidic tumor microenvironment (TME), generated by factors such as excess hydrogen (H + ) ions and high lactate levels, activates immunosuppressive cells, further promoting a suppressive tumor immune microenvironment (TIME). Therefore, a multitarget synergistic combination strategy that neutralizes the acidic TME and reprograms TAMs can be beneficial for OS therapy. Here, a calcium carbonate (CaCO 3 )/polydopamine (PDA)-based nanosystem (A-NPs@(SHK+Ce6)) is developed. CaCO 3 nanoparticles are used to neutralize H + ions and alleviate the suppressive TIME, and the loaded SHK not only synergizes with photodynamic therapy (PDT) but also inhibits lactate production, further reversing the acidic TME and repolarizing TAMs to consequently lead to enhanced PDT-induced tumor suppression and comprehensive beneficial effects on antitumor immune responses. Importantly, A-NPs@(SHK+Ce6), in combination with programmed cell death protein 1 (PD-1) checkpoint blockade, shows a remarkable ability to eliminate distant tumors and promote long-term immune memory function to protect against rechallenged tumors. This work presents a novel multiple-component combination strategy that coregulates the acidic TME and TAM polarization to reprogram the TIME., (© 2024 Wiley‐VCH GmbH.)

Objective: In this study, dentine surface was analysed through Environmental-scanning-electron-microscopy (ESEM) with energy-dispersive-X-ray-spectrometry (EDX) and Fourier-transform-infrared-spectroscopy (FTIR) with attenuated total-reflectance (ATR) to assess the morpho-chemical changes and variations in mineralization degree after demineralizing treatment, after five toothpastes application (HA & Citrate toothpaste, Zinc-HA toothpaste, Calcium Sodium Phosphosilicate toothpaste, Arginine & Calcium carbonate toothpaste, Colgate-Triple-Action, and Control toothpaste), after soaking in artificial saliva and after citric acid attack., Methods: Ca/P, Ca/N and P/N ratios were calculated from EDX atomic data to evaluate the mineralization degree of dentine surface. The IR calcium phosphate (CaP)/collagen and carbonate/collagen ratios has been evaluated to assess the remineralization changes in dentine; the carbonate/collagen IR ratio was calculated to identify the nucleation of B-type-carbonated apatite and calcium carbonate., Results: ESEM-EDX and ATR-FTIR showed residuals of toothpastes after the treatments in all cases, with a general increase in the mineralization degree after soaking in artificial saliva and a decrease after acid attack. Treatment with Arginine & Calcium carbonate toothpaste showed the highest Ca/P value after treatment (Ca/P 1.62) and acid attack (Ca/P 1.5) in confirmation, IR showed the highest amount of carbonate after treatment and soaking in artificial saliva. Arginine and calcium carbonate toothpaste and HA and citrate toothpaste remained to a higher extent on the dentine surface and revealed a higher remineralization activity. These formulations showed higher resistance to demineralization attack, as demonstrated by a higher I CaP /I Amide II intensity ratio than those obtained after EDTA treatment., Conclusions: Toothpastes that remained to a higher extent on dentine surface (arginine and calcium carbonate toothpaste in particular) were more able to promote remineralization. The formed calcium phosphate (CaPs) phase was intimately bound to dentine rather than a simple deposit., (© 2023 The Authors. International Journal of Dental Hygiene published by John Wiley & Sons Ltd.)

Background: Challenges such as poor drug selectivity, non-target reactivity, and the development of drug resistance continue to pose significant obstacles in the clinical application of cancer therapeutic drugs. To overcome the limitations of drug resistance in chemotherapy, a viable treatment strategy involves designing multifunctional nano-platforms that exploit the unique physicochemical properties of tumor microenvironment (TME)., Methods: Herein, layer-by-layer nanoparticles with polyporous CuS as delivery vehicles, loaded with a sonosensitizer (tetra-(4-aminophenyl) porphyrin, TAPP) and sequentially functionalized with pH-responsive CaCO 3 , targeting group hyaluronic acid (HA) were designed and synthesized for synergistic treatment involving chemodynamic therapy (CDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and calcium overload. Upon cleavage in an acidic environment, CaCO 3 nanoparticles released TAPP and Ca 2+ , with TAPP generating 1 O 2 under ultrasound trigger. Exposed CuS produced highly cytotoxic ·OH in response to H 2 O 2 and also exhibited a strong PTT effect., Results: CuS@TAPP-CaCO 3 /HA (CTCH) delivered an enhanced ability to release more Ca 2+ under acidic conditions with a pH value of 6.5, which in situ causes damage to HeLa mitochondria. In vitro and in vivo experiments both demonstrated that mitochondrial dysfunction greatly amplified the damage caused by reactive oxygen species (ROS) to tumor, which strongly confirms the synergistic effect between calcium overload and reactive oxygen therapy., Conclusion: Collectively, the development of CTCH presents a novel therapeutic strategy for tumor treatment by effectively responding to the acidic TME, thus holding significant clinical implications., Competing Interests: The authors declare no competing interest in this work., (© 2024 Zhang et al.)

Starvation therapy has shown promise as a cancer treatment, but its efficacy is often limited when used alone. In this work, a multifunctional nanoscale cascade enzyme system, named CaCO 3 @MnO 2 -NH 2 @GOx@PVP (CMGP), was fabricated for enhanced starvation/chemodynamic combination cancer therapy. CMGP is composed of CaCO 3 nanoparticles wrapped in a MnO 2 shell, with glucose oxidase (GOx) adsorbed and modified with polyvinylpyrrolidone (PVP). MnO 2 decomposes H 2 O 2 in cancer cells into O 2 , which enhances the efficiency of GOx-mediated starvation therapy. CaCO 3 can be decomposed in the acidic cancer cell environment, causing Ca 2+ overload in cancer cells and inhibiting mitochondrial metabolism. This synergizes with GOx to achieve more efficient starvation therapy. Additionally, the H 2 O 2 and gluconic acid produced during glucose consumption by GOx are utilized by MnO 2 with catalase-like activity to enhance O 2 production and Mn 2+ release. This process accelerates glucose consumption, reactive oxygen species (ROS) generation, and CaCO 3 decomposition, promoting the Ca 2+ release. CMGP can alleviate tumor hypoxia by cycling the enzymatic cascade reaction, which increases enzyme activity and combines with Ca 2+ overload to achieve enhanced combined starvation/chemodynamic therapy. In vitro and in vivo studies demonstrate that CMGP has effective anticancer abilities and good biosafety. It represents a new strategy with great potential for combined cancer therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Among different microbial-induced calcium carbonate precipitation (MICCP) mechanisms utilized for biomineralization, ureolysis leads to the greatest yields of calcium carbonate. Unfortunately, it is reported that urea-induced growth inhibition can delay urea hydrolysis but it is not clear how this affects MICCP kinetics. This study investigated the impact of urea addition on the MICCP performance of Lysinibacillus sphaericus MB284 not previously grown on urea (thereafter named bio-agents), compared with those previously cultured in urea-rich media (20 g/L) (hereafter named bio-agents + or bio-agents-plus). While it was discovered that initial urea concentrations exceeding 3 g/L temporarily hindered cell growth and MICCP reactions for bio-agents, employing bio-agents + accelerated the initiation of bacterial growth by 33% and led to a 1.46-fold increase in the initial yield of calcium carbonate in media containing 20 g/L of urea. The improved tolerance of bio-agents + to urea is attributed to the presence of pre-produced endogenous urease, which serves to reduce the initial urea concentration, alleviate growth inhibition, and expedite biomineralization. Notably, elevating the initial concentration of bio-agents + from OD 600 of 0.01 to 1, housing a higher content of endogenous urease, accelerated the initiation of MICCP reactions and boosted the ultimate yield of biomineralization by 2.6 times while the media was supplemented with 20 g/L of urea. These results elucidate the advantages of employing bio-agents + with higher initial cell concentrations to successfully mitigate the temporary inhibitory effects of urea on biomineralization kinetics, offering a promising strategy for accelerating the production of calcium carbonate for applications like bio self-healing of concrete., (Copyright © 2024 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Tumor microenvironment (TME) plays an important role in the tumor progression. Among TME components, cancer-associated fibroblasts (CAFs) show multiple tumor-promoting effects and can induce tumor immune evasion and drug-resistance. Regulating CAFs can be a potential strategy to augment systemic anti-tumor immunity. Here, the study observes that hydrogen treatment can alleviate intracellular reactive oxygen species of CAFs and reshape CAFs' tumor-promoting and immune-suppressive phenotypes. Accordingly, a controllable and TME-responsive hydrogen therapy based on a CaCO 3 nanoparticles-coated magnesium system (Mg-CaCO 3 ) is developed. The hydrogen therapy by Mg-CaCO 3 can not only directly kill tumor cells, but also inhibit pro-tumor and immune suppressive factors in CAFs, and thus augment immune activities of CD4 + T cells. As implanted in situ, Mg-CaCO 3 can significantly suppress tumor growth, turn the "cold" primary tumor into "hot", and stimulate systematic anti-tumor immunity, which is confirmed by the bilateral tumor transplantation models of "cold tumor" (4T1 cells) and "hot tumor" (MC38 cells). This hydrogen therapy system reverses immune suppressive phenotypes of CAFs, thus providing a systematic anti-tumor immune stimulating strategy by remodeling tumor stromal microenvironment., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Interaction of microbiota with hybrid vaterite-pectin microparticles as an attractive multifunctional vehicle for mucosal delivery should not provoke inflammation. Our purpose was to study the reaction of bacteria E. coli strain Mg1655 and isolate SharL from a patient with Crohn disease on the cultivation with hybrid microparticles and vaterite, and the subsequent activation of neutrophils. Vaterite-pectin microparticles enhanced leakage of ATP from bacteria. For E. coli Mg1655, the concentration of DNA decreased, while intracellular ATP increased. For E. coli SharL, the intracellular ATP decreased with simultaneous growth of DNA. Bacteria and microparticles together did not enhance activation of neutrophils in comparison with the particles per se in the medium without serum and in comparison with bacteria in the medium supplemented with serum; microparticles did not reduce functional activity of neutrophils., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Many organisms incorporate inorganic solids into their tissues to improve functional and mechanical properties. The resulting mineralized tissues are called biominerals. Several studies have shown that nacreous biominerals induce osteoblastic extracellular mineralization. Among them, Pinctada margaritifera is well known for the ability of its organic matrix to stimulate bone cells. In this context, we aimed to study the effects of shell extracts from three other Pinctada species (Pinctada radiata, Pinctada maxima, and Pinctada fucata) on osteoblastic extracellular matrix mineralization, by using an in vitro model of mouse osteoblastic precursor cells (MC3T3-E1). For a better understanding of the Pinctada-bone mineralization relationship, we evaluated the effects of 4 other nacreous mollusks that are phylogenetically distant and distinct from the Pinctada genus. In addition, we tested 12 non-nacreous mollusks and one extra-group. Biomineral shell powders were prepared, and their organic matrix was partially extracted using ethanol. Firstly, the effect of these powders and extracts was assessed on the viability of MC3T3-E1. Our results indicated that neither the powder nor the ethanol-soluble matrix (ESM) affected cell viability at low concentrations. Then, we evaluated osteoblastic mineralization using Alizarin Red staining and we found a prominent MC3T3-E1 mineralization mainly induced by nacreous biominerals, especially those belonging to the Pinctada genus. However, few non-nacreous biominerals were also able to stimulate the extracellular mineralization. Overall, our findings validate the remarkable ability of CaCO 3 biomineral extracts to promote bone mineralization. Nevertheless, further in vitro and in vivo studies are needed to uncover the mechanisms of action of biominerals in bone., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Antimicrobial coatings provide protection against microbes colonization on surfaces. This can prevent the stabilization and proliferation of microorganisms. The ever-increasing levels of microbial resistance to antimicrobials are urging the development of alternative types of compounds that are potent across broad spectra of microorganisms and target different pathways. This will help to slow down the development of resistance and ideally halt it. The development of composite antimicrobial coatings (CACs) that can host and protect various antimicrobial agents and release them on demand is an approach to address this urgent need. In this work, new CACs based on microsized hybrids of calcium carbonate (CaCO 3 ) and silver nanoparticles (AgNPs) were designed using a drop-casting technique. Polyvinylpyrrolidone and mucin were used as additives. The CaCO 3 /AgNPs hybrids contributed to endowing colloidal stability to the AgNPs and controlling their release, thereby ensuring the antibacterial activity of the coatings. Moreover, the additives PVP and mucin served as a matrix to (i) control the distribution of the hybrids, (ii) ensure mechanical integrity, and (iii) prevent the undesired release of AgNPs. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) techniques were used to characterize the 15 μm thick CAC. The antibacterial activity was determined against Escherichia coli , methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa , three bacteria responsible for many healthcare infections. Antibacterial performance of the hybrids was demonstrated at concentrations between 15 and 30 μg/cm 2 . Unloaded CaCO 3 also presented bactericidal properties against MRSA. In vitro cytotoxicity tests demonstrated that the hybrids at bactericidal concentrations did not affect human dermal fibroblasts and human mesenchymal stem cell viability. In conclusion, this work presents a simple approach for the design and testing of advanced multicomponent and functional antimicrobial coatings that can protect active agents and release them on demand.

The ideal and highly anticipated dressing for skin wounds should provide a moist environment, possess antibacterial properties, and ensure sustained drug release. In the present work, a hyaluronic acid-based hydrogel was formed by cross-linking crocetin and CaCO 3 @polyelectrolyte materials (CaCO 3 @PEM) microspheres with HA hydrogels via hydrogen bond and amido bonding (CaCO 3 @PEM@Cro@HA hydrogel, CPC@HA hydrogel). Moreover, the CPC@HA hydrogel had the capability of sustained, controlled release of calcium ions and crocetin via pH-sensitive and accelerated skin wound healing. The experiment results showed that the CPC@HA hydrogel exhibited porous network structures, stable physical properties, and had antibacterial properties and biocompatibility in vitro. In addition, the CPC@HA hydrogel covering on the skin wound could reduce inflammation and promote wound healing. The high expression of angiogenic cytokines (CD31) and epidermal terminal differentiation markers (Loricrin) of wound healing tissue suggested the CPC@HA hydrogel also had the function of promoting the remodeling of regenerated skin. Overall, CPC@HA hydrogel has promising potential for clinical applications in accelerating skin wound repair., (© 2024 Wiley-VCH GmbH.)

In this study, the formation of protein microspheres through lysosomal enzyme-assisted biomineralized crystallization was demonstrated. Spherical micro-sized hybrid CaCO 3 constructs were synthesized and characterized using field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and particle size analysis. Additionally, parameters such as the Brunauer-Emmett-Teller surface area and single-point total pore volume, and adsorption/desorption analysis were used to investigate the mesoporous properties, which are advantageous for lysosomal enzyme (LE) loading. A LE can be used as an organic template, not only as a morphological controller but also for entrapping LE during the crystallization pathway. The hybrid protein microspheres accommodated 2.3 mg of LE with a 57% encapsulation efficiency and 5.1 wt% loading. The peroxidase activity of the microspheres was calculated and found to be approximately 0.0238 mM -1 min -1 . pH-responsive release of the LE from CaCO 3 was observed, suggesting potential biomedical and cosmetic applications in acidic environments. The hybrid LE microsphere treatment significantly alleviated melanin production in a dose-dependent manner and further downregulated the mRNA expression of MITF, tyrosinase, TYRP-1, and TYRP-2. These results indicate skin-whitening effects by inhibiting melanin without inducing cytotoxicity. The data provide the first evidence of the potential use of a LE for obtaining hybrid minerals and the effectiveness of biomineralization-based sustainable delivery of enzyme-based vehicles based on organelle-extract-assisted biomineralization.

Memantine, an N-Methyl-D-Aspartate (NMDA) antagonist, has been examined as a potential treatment for Obsessive-Compulsive Disorder (OCD). Yet, there is limited knowledge regarding how it works to reduce compulsive behaviour and whether it has different effects on individuals based on their sex. Herein, we investigated if there are sex differences in the anticompulsive-like effect of memantine in adult Swiss mice. Additionally, we explored whether the nitric oxide (NO) pathway and α-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) receptors play a role in memantine's effects. To start, we assessed the impact of a single intraperitoneal dose of memantine (at 3, 5, and 10 mg/kg) on behaviours exhibited in the open field test (OFT) and the marble-burying test (MBT), the latter being a predictive test for anticompulsive effects. All doses of memantine reduced marble-burying behaviour in both male and female mice without affecting their locomotor activity in the OFT. This anticompulsive-like effect was also confirmed in another predictive test, the nest-building test, with the highest memantine dose (10 mg/kg) reducing nest-building behaviour without significant differences between male and female mice. We observed that pre-treatment with L-arginine, a NO precursor, mitigated the anticompulsive-like effect of memantine in male mice but had no effect in female mice in the MBT. Finally, NBQX, an AMPA receptor antagonist, did not block the anticompulsive-like effect of memantine. In summary, our study suggests that the anticompulsive-like effect of memantine does not appear to be sex-specific, does not depend on AMPA receptors, and involves the NO pathway primarily in male mice., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In 2016, the National Institutes of Health mandated the use of both male and female mice in funded research. The use of both sexes is an important variable to consider; however, it comes with negative consequences such as increased animal expenses. One way to combat these negatives is to explore the option of using a within-subjects design (repeated measures) in behavioral assays that historically use a between-subjects design. Our study aimed to determine if a within-subjects design can be utilized in the marble burying assay. The marble burying assay is used as a tool for screening putative anxiolytic compounds as the assay is thought to measure obsessive-compulsive disorder- or anxiety-like behaviors. First, we compared the effects of sex and digging medium (corn cob or Sani Chip) on the number of marbles buried using CD-1 mice. Second, we determined if mice would continue to bury marbles after repeated exposures to the test arena. Lastly, we tested three positive controls (buspirone, ketamine, and fluoxetine). We found that mice buried significantly more marbles within Sani Chip digging medium, and no sex differences were observed. Next, the number of marbles buried and locomotor activity remained consistent across four test sessions. The positive controls buspirone (3.2-10 mg/kg) ketamine (32 mg/kg), and fluoxetine (10 mg/kg) decreased the number of marbles buried using the within-subjects design. These data suggest that a within-subjects design is optimal for the marble burying assay as it will reduce the number of animals and increase statistical power., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

The application of vaterite microparticles for mucosal delivery depends on their interaction with mucin and immune cells. As we have shown previously, the binding of mucin onto particles enhances the generation of reactive oxygen species by neutrophils. The attenuation of the pro-oxidant effect of the bound mucin through the modification of vaterite could improve its biocompatibility. Hybrid microparticles composed of vaterite and pectin (CCP) were prepared using co-precipitation. In comparison with vaterite (CC), they had a smaller diameter and pores, a greater surface area, and a negative zeta-potential. We aimed to study the cytotoxicity and mucin-dependent neutrophil-activating effect of CCP microparticles. The incorporated pectin did not influence the neutrophil damage according to a lactate dehydrogenase test. The difference in the CC- and CCP-elicited luminol or lucigenin chemiluminescence of neutrophils was insignificant, with no direct pro- or antioxidant effects from the incorporated pectin. Unlike soluble pectin, the CCP particles were ineffective at scavenging radicals in an ABAP-luminol test. The fluorescence of SYTOX Green demonstrated a CCP-stimulated formation of neutrophil extracellular traps (NETs). The pre-treatment of CC and CCP with mucin resulted in a 2.5-times-higher CL response of neutrophils to the CC-mucin than to the CCP-mucin. Thus, the incorporation of pectin into vaterite microspheres enabled an antioxidant effect to be reached when the neutrophils were activated by mucin-treated microparticles, presumably via exposed ligands.

Breast cancer is resistant to conventional treatments due to the specific tumour microenvironment, the associated acidic pH and the overexpression of receptors that enhance cells tumorigenicity. Herein, we optimized the synthesis of acidic resorbable calcium carbonate (CaCO 3 ) nanoparticles and the encapsulation of a low molecular weight model molecule (Rhodamine). The addition of ethylene glycol during the synthetic process resulted in a particle size decrease: we obtained homogeneous CaCO 3 particles with an average size of 564 nm. Their negative charge enabled the assembly of layer-by-layer (LbL) coatings with surface-exposed hyaluronic acid (HA), a ligand of tumour-associated receptor CD44. The coating decreased Rhodamine release by two-fold compared to uncoated nanoparticles. We demonstrated the effect of nanoparticles on two breast cancer cell lines with different aggressiveness - SK-BR-3 and the more aggressive MDA-MB-231 - and compared them with the normal breast cell line MCF10A. CaCO 3 nanoparticles (coated and uncoated) significantly decreased the metabolic activity of the breast cancer cells. The interactions between LbL-coated nanoparticles and cells depended on HA expression on the cell surface: more particles were observed on the surface of MDA-MB-231 cells, which had the thickest endogenous HA coating. We concluded that CaCO 3 nanoparticles are potential candidates to carry low molecular weight chemotherapeutics and deliver them to aggressive breast cancer sites with an HA-abundant pericellular matrix., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: The aim of this study was to compare the addition in culture media of stabilized amorphous calcium carbonate (ACC) versus calcium chloride (CaCl 2 ) or calcium carbonate in crystalline form (CCC) on growth rates among sibling mouse embryos., Methods: We evaluated the effect of different ACC concentrations on the rates of embryo compaction at 60 h, blastocyst rate at 84 h and percentage of fully hatched at 108 h following hCG injection. As ACC is stabilized by tripolyphosphate (TPP), we also evaluated the addition of TPP alone to the culture media. Finally, we compared supplemented ACC culture media to one-step SAGE and Irvine cleavage media., Results: The results revealed that ACC accelerates the compaction and blastocyst rates, as well as the percentage of fully hatched embryos in a dose-dependent manner, with an increased positive effect at 2.5 mM. The magnitude of the effect for ACC-supplemented media on the embryo developmental rate was between 30 to 40% (p < 0.01) faster for each stage, compared to both SAGE and Irvine one-step standard media. Embryos cultured with SAGE or Irvine media with or without supplementation of CaCl 2 or CCC, did not produce the same improvements as observed with ACC., Conclusion: In conclusion, the ACC demonstrates a rapid modulation effect for restoring media optimal pH. ACC can inhibit cathepsin B activity during in vitro culture of fibroblast cells. The beneficial impact of ACC on cleavage mouse embryos is likely due to an improved buffering effect causing slower pH media variations, which may enhance quality and implantation potential of embryos following in vitro culture., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This study aimed to evaluate the efficacy of calcium carbonate nanoparticles (CCNPs) to induce new bone formation in a critical size segmental bone defect in rabbit's radius when used alone, combined with silver nanoparticles (AgNPs) as a paste, or as a composite containing CCNPs, AgNPs, and advanced platelet-rich fibrin (A-PRF). Thirty-six adult apparently healthy male New Zealand White rabbits aging from 5 to 6 months and weighting 3.5 ± 0.5 kg were used. The animals were divided into four groups; control group, CCNPs group, CCNPs/AgNPs paste group, and CCNPs/AgNPs/A-PRF composite group. The animals were investigated at 4, 8, and 12 weeks post-implantation in which the healing was evaluated using computed tomographic (CT) and histopathological evaluation. The results revealed that CCNPs/AgNPs paste and CCNPs/AgNPs/A-PRF composite has a superior effect regarding the amount and the quality of the newly formed bone compared to the control and the CCNPs alone. In conclusion, addition of AgNPs and/or A-PRF to CCNPs has reduced its resorption rate and improved its osteogenic and osteoinductive properties., (© 2023. Springer Nature Limited.)

Calcium (Ca) is a vital component of the human body and plays a crucial role in intracellular signaling and regulation as a second messenger. Recent studies have shown that changes in intracellular Ca 2+ concentration can influence immune cell function. In this study, we developed calcium carbonate nanoparticles (CaNPs) of various sizes using a Nanosystem Platform to modulate intracellular Ca 2+ concentration in vitro and in vivo. Our findings demonstrate that intravenous administration of CaNPs led to changes in the number and ratio of immune cells in the spleen and stimulated the activation of dendritic cells (DCs) and macrophages. Notably, CaNPs exhibited strong adjuvant properties in the absence of antigenic stimuli. These results indicate that CaNPs have the potential to regulate immune cell function by modulating Ca 2+ concentrations, offering a novel approach for disease prevention and treatment in combination with antigens or drugs. Overall, our study emphasizes the importance of modulating intracellular Ca 2+ concentration as a means of regulating immune cell function.

To modify an adhesive system with halloysite clay nanotubes (HNTs) containing arginine and calcium carbonate and to evaluate their cytocompatibility, viscosity and efficacy in reducing dentin permeability. HNTs containing arginine and calcium carbonate were incorporated into the primer and adhesive of a three-step adhesive system (SBMP), and their viscosity was measured. Discs (n = 4/group) were prepared: SBMP (control), HNT-PR (modified primer), HNT-ADH (modified adhesive) and HNT-PR + ADH (modified primer and adhesive) were evaluated regarding cell death and viability. Dentin discs were prepared and randomly assigned into the following treatments (n = 10): NC (no treatment), SBMP, HNT-PR, HNT-ADH, HNT-PR + ADH and COL (Colgate® Sensitive Pro-relief™ prophylaxis paste). After, they were submitted to an erosive-abrasive cycling. Dentin permeability (hydraulic conductance) was evaluated at baseline, 24 h after treatment and after cycling. Both the modified primer and adhesive showed significantly higher viscosity than their controls. Group HNT-PR resulted in significantly higher cytotoxicity when compared to SBMP and HNT-PR + ADH groups. Group HNT-ADH resulted in the highest cell viability compared to all other groups. All groups showed significantly lower dentin permeability when compared to the NC group. Post-cycling, SBMP and HNT-ADH groups showed significantly lower permeability when compared to COL group. The addition of encapsulated arginine and calcium carbonate did not affect the cytocompatibility of the materials nor their ability to reduce dentin permeability., (© 2023 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials published by Wiley Periodicals LLC.)

Calcium carbonate (CaCO 3 ) exhibits a variety of crystalline phases, including the anhydrous crystalline polymorphs calcite, aragonite, and vaterite. Developing porous calcium carbonate microparticles in the vaterite phase for the encapsulation of methylene blue (MB) as a photosensitizer (PS) for use in photodynamic therapy (PDT) was the goal of this investigation. Using an adsorption approach, the PS was integrated into the CaCO 3 microparticles. The vaterite microparticles were characterized by scanning electron microscopy (SEM) and steady-state techniques. The trypan blue exclusion method was used to measure the biological activity of macrophages infected with Leishmania braziliensis in vitro. The vaterite microparticles produced are highly porous, non-aggregated, and uniform in size. After encapsulation, the MB-loaded microparticles kept their photophysical characteristics. The carriers that were captured allowed for dye localization inside the cells. The results obtained in this study indicated that the MB-loaded vaterite microparticles show promising photodynamic activity in macrophages infected with Leishmania braziliensis., (© 2023. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)

Magnesium phosphate cement (MPC) has been evaluated as a novel bone substitute owing to its favorable biocompatibility, plasticity, and osteogenic potential. However, the low porosity of MPC prevents growth factors and osteoblasts from fully growing into the material, thereby limiting its clinical use. In this study, different concentrations (0-5%) of calcium carbonate and citric acid (CA) were used as foaming agents to prepare porous MPC. The MPC containing 3% CaCO 3 /CA exhibited the best physicochemical properties, including greater porosity, improved injectability, extended setting time, and decreased hydration temperature. The proliferation and adhesion of cells on 3%CaCO 3 /CA-MPC were higher than those on MPC alone. To explore its osteogenesis in vivo, 3% CaCO 3 /CA-MPC and Bio-Oss® bone powder were implanted into periodontal bone defects in rats for 4 weeks and 12 weeks, respectively. Micro-CT and histological analysis demonstrated the improved bone regeneration of 3%CaCO 3 /CA-MPC compared to the blank group (P < 0.05); it had slightly lower bone regeneration than the Bio-Oss® group but no statistical difference. The results indicated that porous MPC foamed with calcium carbonate and CA improved its physicochemical properties and enhanced its biocompatibility, making it a promising material for bone regeneration., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The search for novel therapeutic strategies to treat fungal diseases is of special importance nowadays given the emerging threat of drug resistance. Various particulate delivery systems are extensively being developing to enhance bioavailability, site-specific penetration, and therapeutic efficacy of antimycotics. Recently, we have designed a novel topical formulation for griseofulvin (Gf) drug, which is currently commercially available in oral dosage forms due to its limited skin permeation. The proposed formulation is based on vaterite carriers that enabled effective incorporation and ultrasonically assisted delivery of Gf to hair follicles improving its dermal bioavailability. Here, we evaluated the effect of ultrasound on the viability of murine fibroblasts co-incubated with either Gf-loaded carriers or a free form of Gf and investigated the influence of both forms on different subpopulations of murine blood cells. The study revealed no sufficient cyto- and hemotoxicity of the carriers, even at the highest investigated concentrations. We also conducted a series of in vivo experiments to assess their multi-dose dermal toxicity and antifungal efficiency. Visual and histological examinations of the skin in healthy rabbits showed no obvious adverse effects after US-assisted application of the Gf-loaded carriers. At the same time, investigation of therapeutic efficiency for the designed formulation in comparison with free Gf and isoconazole drugs in a guinea pig model of trichophytosis revealed that the vaterite-based form of Gf provided the most rapid and effective cure of infected animals together with the reduction in therapeutic procedure number. These findings pave the way to improving antifungal therapy of superficial mycoses and justifying further preclinical studies.

The effect of microbial phytase and limestone particle size (LmPS) was assessed in Lohmann Tradition laying hens from 31 to 35 wk of age. Seventy-two hens were used in a completely randomized trial according to a 2 × 2 factorial arrangement with 2 levels of phytase/basal available P (aP); 0 FTU/kg with 0.30% aP or 300 FTU/kg with 0.15% aP, and 2 limestone particle sizes; fine particles (FL, <0.5 mm) or a mix (MIX) of 75% coarse limestone (CL, 2-4 mm) and 25% FL. Diets contained equivalent levels of Ca (3.5%), phytic P (PP; 0.18%), and aP (0.30%) considering the P equivalency of phytase. Thus, dietary treatments were FL0 and MIX0 without phytase, and FL300 and MIX300 with 300 FTU/kg phytase. Performance were recorded daily and eggshell quality (eggshell weight proportion, weight, thickness, and breaking strength) was measured weekly. At the end of the trial, bone parameters (tibia breaking strength, elasticity, and ash) and the apparent precaecal digestibility (APCD) of P and Ca were determined. No differences were observed between treatments in feed intake, FCR and bone parameters. Addition of MIX increased the eggshell proportion, weight and thickness in groups receiving no phytase (+6.5, +6.9, and +4.5%, respectively) while no effect was observed in groups receiving phytase (Phytase × LmPS, P < 0.05). In hens receiving FL, the APCD of P was lower in diets supplemented with phytase (-14 percentage points; Phytase × LmPS, P < 0.001). A higher phytate disappearance was observed in hens fed diets with phytase in combination with MIX (Phytase × LmPS, P = 0.005). Phytase and MIX together increased the APCD of Ca by 7.3 percentage points (Phytase × LmPS, P < 0.001). In conclusion, addition of CL could limit the formation of Ca-phytate complex thus improving the response of the birds to phytase compared to FL., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The present study aimed to investigate the biocompatibility, antibacterial/anti-biofilm effects of ciprofloxacin-loaded calcium carbonate (Cip- loaded CaCO 3 ) nanoparticles against the common organisms responsible for osteomyelitis. The antibacterial and biofilm inhibitory activities were studied by determination of minimum inhibitory concentrations (MICs) and minimum biofilm inhibitory concentrations (MBICs), respectively. Hemolytic effects were determined for studying hemocompatibility. The SDS-PAGE method was used to study the interaction of Cip- loaded CaCO 3 with plasma proteins. The effects of Cip- loaded CaCO 3 on the cell viability of human bone marrow mesenchymal stem cells (hBM-MSCs) was detected. The Cip- loaded CaCO 3 nanoparticles were shown a significant antimicrobial effect at lower concentrations than free ciprofloxacin. No significant hemolytic effect was observed. The Cip- loaded CaCO 3 nanoparticles have shown interaction with apolipoprotein A1 (28 kDa) and albumin (66.5 kDa). The viability of hBM-MSCs treated with Cip- loaded CaCO 3 was more than 96%. Our results indicated that Cip-loaded CaCO 3 nanoparticles had favorable in vitro compatibility with human red blood cells, antimicrobial effects, and low cytotoxicity., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The growing biomedical challenges impose the continuous development of novel platforms. Ensuring the biocompatibility of drug delivery and implantable biomedical devices is an essential requirement. Calcium carbonate (CaCO3) in the form of vaterite nanoparticles is a promising platform, which has demonstrated distinctive optical and biochemical properties, including high porosity and metastability. In this study, the biocompatibility of differently shaped CaCO 3 vaterite particles (toroids, ellipsoids, and spheroids) are evaluated by bacterial toxicity mode-of-action with a whole-cell biosensor. Different Escherichia coli (E. coli) strains were used in the bioluminescent assay, including cytotoxicity, genotoxicity and quorum-sensing. Firstly, both scanning electron microscopy (SEM) and fluorescence microscopy characterizations were conducted. Bacterial cell death and aggregates were observed only in the highest tested concentration of the vaterite particles, especially in toroids 15-25 µm. After, the bioluminescent bacterial panel was exposed to the vaterite particles, and their bioluminescent signal reflected their toxicity mode-of-action. The vaterite particles resulted in an induction factor (IF > 1) on the bacterial panel, which was higher after exposure to the toroids (1.557 ≤ IF ≤ 2.271) and ellipsoids particles (1.712 ≤ IF ≤ 2.018), as compared to the spheroids particles (1.134 ≤ IF ≤ 1.494), in all the tested bacterial strains. Furthermore, the vaterite particles did not affect the viability of the bacterial cells. The bacterial monitoring demonstrated the biofriendly nature of especially spheroids vaterite nanoparticles., Competing Interests: Declaration of Competing Interest The authors declared no potential conflicts of interest concerning the research, authorship, and/or publication of this article., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective: The aim of the study is to investigate whether nano-calcium carbonate (nano-CaCO 3 ) occupational exposure could induce adverse health effects in workers., Methods: A cross-sectional study was conducted in a nano-CaCO 3 manufacturing plant in China. Then, we have studied the dynamic distribution of nano-CaCO 3 in nude mice and examined the oxidative damage biomarkers of subchronic administrated nano-CaCO 3 on Sprague-Dawley rats., Results: The forced vital capacity (%) and the ratio of FEV1 to FVC is the rate of one second of workers were significantly decreased than unexposed individuals. Dynamic imaging in mice of fluorescence labeled nano-CaCO 3 showed relatively high uptake and slow washout in lung. Similar to population data, the decline in serum glutathione level and elevation in serum MDA were observed in nano-CaCO 3 -infected Sprague-Dawley rats., Conclusions: We found that nano-CaCO 3 exposure may result in the poor pulmonary function in workers and lead to the changes of oxidative stress indexes., Competing Interests: Conflict of interests: None declared., (Copyright © 2022 American College of Occupational and Environmental Medicine.)

Postmenopausal osteoporosis transpires due to excessive osteoclastic bone resorption and insufficient osteoblastic bone formation in the presence of oestrogen insufficiency. Kang Shuai Lao Pian (KSLP) is a red ginseng-based traditional Chinese medicine known for its anti-ageing properties. However, studies on its effect on bone loss are lacking. Thus, the current study examined the skeletal protective effects of KSLP in an ovariectomised rodent bone loss model. Three-month-old female Sprague Dawley rats (n=42) were randomised into baseline, sham and ovariectomised (OVX) groups. The OVX rats were supplemented with low- (KSLP-L; 0.15 g/kg), medium- (KSLP-M; 0.30 g/kg), high-dose KSLP (KSLP-H; 0.45 g/kg) or calcium carbonate (1% w/v). The daily supplementation of KSLP was performed via oral gavage for eight weeks. Gavage stress was stimulated in the ovariectomised control with distilled water. The rats were euthanised at the end of the study. Whole-body and femoral bone mineral content and density scans were performed at baseline and every four weeks. Blood samples were obtained for the determination of bone remodelling markers. Histomorphometry and biomechanical strength testing were performed on femurs and tibias. High bone remodelling typically due to oestrogen deficiency, indicated by the elevated bone formation and resorption markers, osteoclast surface, single-labelled surface and mineralising surface/bone surface ratio, was observed in the untreated OVX rats. Whole-body BMD adjusted to body weight and Young's modulus decreased significantly in the untreated OVX rats. High-dose KSLP supplementation counteracted these degenerative changes. In conclusion, KSLP improves bone health by normalising bone remodelling, thereby preventing bone loss and decreased bone strength caused by oestrogen deficiency. Its anti-osteoporosis effects should be validated in patients with postmenopausal osteoporosis., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Nano- and microparticles enter the body through the respiratory airways and the digestive system, or form as biominerals in the gall bladder, salivary glands, urinary bladder, kidney, or diabetic pancreas. Calcium, magnesium, and phosphate ions can precipitate from biological fluids in the presence of mucin as hybrid nanoparticles. Calcium carbonate nanocrystallites also trap mucin and are assembled into hybrid microparticles. Both mucin and calcium carbonate polymorphs (calcite, aragonite, and vaterite) are known to be components of such biominerals as gallstones which provoke inflammatory reactions. Our study was aimed at evaluation of neutrophil activation by hybrid vaterite-mucin microparticles (CCM). Vaterite microparticles (CC) and CCM were prepared under standard conditions. The diameter of CC and CCM was 3.3 ± 0.8 µm and 5.8 ± 0.7 µm, with ƺ-potentials of -1 ± 1 mV and -7 ± 1 mV, respectively. CC microparticles injured less than 2% of erythrocytes in 2 h at 1.5 mg mL -1 , and no hemolysis was detected with CCM; this let us exclude direct damage of cellular membranes by microparticles. Activation of neutrophils was analyzed by luminol- and lucigenin-dependent chemiluminescence (Lum-CL and Luc-CL), by cytokine gene expression (IL-6, IL-8, IL-10) and release (IL-1β, IL-6, IL-8, IL-10, TNF-α), and by light microscopy of stained smears. There was a 10-fold and higher increase in the amplitude of Lum-CL and Luc-CL after stimulation of neutrophils with CCM relative to CC. Adsorption of mucin onto prefabricated CC microparticles also contributed to activation of neutrophil CL, unlike mucin adsorption onto yeast cell walls (zymosan); adsorbed mucin partially suppressed zymosan-stimulated production of oxidants by neutrophils. Preliminary treatment of CCM with 0.1-10 mM NaOCl decreased subsequent activation of Lum-CL and Luc-CL of neutrophils depending on the used NaOCl concentration, presumably because of the surface mucin oxidation. Based on the results of ELISA, incubation of neutrophils with CCM downregulated IL-6 production but upregulated that of IL-8. IL-6 and IL-8 gene expression in neutrophils was not affected by CC or CCM according to RT 2 -PCR data, which means that post-translational regulation was involved. Light microscopy revealed adhesion of CC and CCM microparticles onto the neutrophils; CCM increased neutrophil aggregation with a tendency to form neutrophil extracellular traps (NETs). We came to the conclusion that the main features of neutrophil reaction to mucin-vaterite hybrid microparticles are increased oxidant production, cell aggregation, and NET-like structure formation, but without significant cytokine release (except for IL-8). This effect of mucin is not anion-specific since particles of powdered kidney stone (mainly calcium oxalate) in the present study or calcium phosphate nanowires in our previous report also activated Lum-CL and Luc-CL response of neutrophils after mucin sorption.

To investigate the changes in bone mineral density, bone metabolism, and efficacy of nutritional intervention combined with calcium carbonate D3 tablets in patients with osteoporosis, a RevMan 5.2 software meta-analysis was conducted in this study. According to the therapeutic direction of nutritional intervention combined with calcium carbonate D3 tablets for osteoporosis patients, relevant literature were searched in Wanfang Medical, CNKI, VIP, and PubMed literature databases at home and abroad. Keywords included bone mineral density, bone metabolism, blood calcium (Ca), blood phosphorus (P), osteocalcin (OC), bone mineral density (BMD), serum alkaline phosphatase (ALP), efficacy, osteoporosis, and nutritional intervention. Literature that met the criteria were deleted, and meta-analysis was performed using RevMan 5.2 software. The results indicate that a total of 10 Chinese literature were included. Compared with the monotherapy group, the clinical efficacy, osteocalcin, BMD, alkaline phosphatase, calcium, and phosphorus were significantly higher in the combination group ( P  < 0.05). Based on calcium carbonate D3, treatment combined with nutritional intervention can enhance the clinical efficacy, bone metabolism, and bone mineral density of patients with osteoporosis, and nutritional intervention combined with calcium carbonate D3 tablets is a feasible program to promote the recovery of patients with osteoporosis., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Hua Ni et al.)

Artesunate (AS), the first-line treatment of malaria with a satisfactory safety profile, has been repurposed as a potential anticancer candidate as it mainly generates reactive oxygen species (ROS) through its intrinsic endoperoxide bridge reacting with ferrous-based catalysts to suppress cancer cell growth. However, further clinical translation of AS is hindered by the attenuated anticancer efficacy due to insufficient ROS generation. Herein, we rationally integrated hydrophobic-modified AS (hAS) with biomimetic polydopamine (PDA) and biomineral calcium carbonate to fabricate high AS-loaded nanomedicine (Ca-PDA/hAS@PEG) for cancer chemo-photothermal therapy, which exerted anticancer effects in the following ways: (1) the heat was generated when PDA was irradiated by near-infrared (NIR) light for photothermal therapy. Meanwhile, the increased temperature accelerated the production of ROS from hAS, thus enhancing the anticancer efficacy of hAS-based chemotherapy; (2) hAS-mediated chemotherapy boosted the cancer inhibition effect of photothermal therapy by arousing the intracellular ROS levels in the presence of endogenous ferrous ions and sensitizing cancer cells to thermal ablation; (3) the integration of calcium carbonate into the nanoparticle facilitated the pH-responsive drug release for precise treatment. Such hybrid nanoparticles exhibited a combinational antitumor effect of photothermal therapy and chemotherapy in vivo with no systemic toxicity. Taken together, our work presents a facile strategy to improve the anticancer efficacy of AS by combining chemical modification and photothermal therapy-assisted endoperoxide bridge cleavage, which may offer opportunities to pave the way for clinical translation of AS-based nanomedicines. STATEMENT OF SIGNIFICANCE: The clinical translation of artesunate (AS) is hindered by the attenuated anticancer efficacy due to insufficient ROS generation. Herein, we rationally integrated hydrophobic-modified AS (hAS) with biomimetic polydopamine (PDA) and biomineral calcium carbonate to fabricate high AS-loaded nanomedicine (Ca-PDA/hAS@PEG) for improved cancer chemo-photothermal therapy. The heat generated from PDA in response to near-infrared light irradiation could locally ablate tumor as well as accelerate the production of ROS by hAS, thus enhancing the anticancer efficacy of hAS-based chemotherapy. On the other hand, hAS-based chemotherapy amplified the intracellular oxidative stress, sensitizing cancer cells to thermal ablation. Our work presents a facile strategy to improve the anticancer efficacy of AS by combining chemical modification and photothermal therapy-assisted endoperoxide bridge cleavage., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier Ltd.)

The marble bury test is a commonly applied behavioral test often used to screen pharmaceuticals for treatment of compulsivity or anxiety disorders and to better understand the underlying neurobiology of these conditions using rodent models. We explore the use of the marble bury test in a repeated fashion over longer time intervals to assess how it may be used in a more chronic context. Assuming that marble bury scores represent a neurobiological phenotype of an individual, we hypothesize that the measurement of this phenotype is repeatable over time in a healthy animal. We performed four trials over the course of 12 weeks, using three overlapping scores for marble burying: 100%, >50%, and >0% buried. Despite intertrial differences in the mean number of marbles buried, we found significant repeatability scores across 12 weeks for two measurements: marbles buried 100% and marbles buried >50%. Exploration of pairwise repeatabilities between the trials revealed highest repeatability during shorter time intervals. Although the effect of time is difficult to disentangle from possible effects of body size/development on the scores, we hypothesize that a combination of these two factors together influence repeatability of scores and should be explored further. Understanding the patterns in repeatability in marble burying scores can inform experimental design to use this test over longer time intervals for chronic conditions or long-term interventions. Additionally, these data indicate that a pre-test, post-test design is possible, which can reduce the number of animals needed for research applications while maintaining statistical power., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Autism spectrum disorder (ASD) is a neurodevelopmental disease characterized by impaired communication, impaired reciprocal social interaction, restricted sociability deficits, and the presence of stereotyped patterns of behaviors. Immune dysregulation has been suggested to play a possible etiological role in ASD. Recent studies have demonstrated that exposure to methylmercury chloride (MeHgCl) leads to abnormal gait, motor deficits, impaired hearing, and memory deficits; however, its effects on behavioral and immunological responses have not been adequately investigated in ASD. In this study, we investigated the effects of MeHgCl exposure on marble burying, self-grooming behaviors, sociability tests, and locomotor activities in BTBR T + Itpr3tf/J (BTBR) mice. We also explored the possible molecular mechanism underlying the effects of MeHgCl administration on IFN-γ-, T-bet-, IL-9-, and IL-17A-producing CD4 + , CXCR5 + , CXCR6 + , and CCR9 + cells isolated from spleens. Furthermore, the effects of MeHgCl exposure on the mRNA expression and levels of pro-inflammatory cytokines in the brain tissue and serum samples were also assessed. Our results demonstrated that MeHgCl exposure caused a significant increase in marble burying, self-grooming behaviors and a decrease in social interactions and adverse effects on locomotor activity in BTBR mice. MeHgCl exposure also significantly increased the production of CD4 + IFN-γ + , CD4 + T-bet + , CCR9 + T-bet + , CXCR5 + IL-9 + , CD4 + IL-9 + , CXCR6 + IL-17A + , and CD4 + IL-17A + cells in the spleen. Furthermore, MeHgCl exposure increased mRNA and protein levels of pro-inflammatory cytokines in the brain and serum respectively in BTBR mice. In conclusion, MeHgCl administration aggravated existing behavioral and immune abnormalities in BTBR mice., (Copyright © 2022 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.)

Injectable bone substitutes (IBS) are increasingly being used in the fields of orthopedics and maxillofacial/oral surgery. The rheological properties of IBS allow for proper and less invasive filling of bony defects. Vaterite is the most unstable crystalline polymorph of calcium carbonate and is known to be able to transform into hydroxyapatite upon contact with an organic fluid (e.g., interstitial body fluid). Two different concentrations of hydrogels based on poly(ethylene glycol)-acetal-dimethacrylat (PEG-a-DMA), i.e., 8% ( w / v ) (VH-A) or 10% ( w / v ) (VH-B), were combined with vaterite nanoparticles and implanted in subcutaneous pockets of BALB/c mice for 15 and 30 days. Explants were prepared for histochemical staining and immunohistochemical detection methods to determine macrophage polarization, and energy-dispersive X-ray analysis (EDX) to analyze elemental composition was used for the analysis. The histopathological analysis revealed a comparable moderate tissue reaction to the hydrogels mainly involving macrophages. Moreover, the hydrogels underwent a slow cellular infiltration, revealing a different degradation behavior compared to other IBS. The immunohistochemical detection showed that M1 macrophages were mainly found at the material surfaces being involved in the cell-mediated degradation and tissue integration, while M2 macrophages were predominantly found within the reactive connective tissue. Furthermore, the histomorphometrical analysis revealed balanced numbers of pro- and anti-inflammatory macrophages, demonstrating that both hydrogels are favorable materials for bone tissue regeneration. Finally, the EDX analysis showed a stepwise transformation of the vaterite particle into hydroxyapatite. Overall, the results of the present study demonstrate that hydrogels including nano-vaterite particles are biocompatible and suitable for bone tissue regeneration applications.

Background: Asymmetric intracellular and extracellular ionic gradients are critical to the survivability of mammalian cells. Given the importance of manganese (Mn 2+ ), calcium (Ca 2+ ), and bicarbonate (HCO 3 - ) ions, any alteration of the ion-content balance could induce a series of cellular responses. HCO 3 - plays an indispensable role for Mn-mediated Fenton-like reaction, but this is difficult to achieve because bicarbonates are tightly regulated by live cells, and are limited in anticancer efficacy. Methods: A responsive and biodegradable biomineral, Mn-doped calcium carbonate integrated with dexamethasone phosphate (DEX) (Mn:CaCO 3 -DEX), was reported to enable synergistic amplification of tumor oxidative stress, reduce inflammation, and induce Ca-overload cell apoptosis by elevating the intracellular and extracellular ionic gradients. Results: Under the acidic environment in tumor region, the ions (Mn 2+ , CO 3 2- , Ca 2+ ) were released by the degradation of Mn:CaCO 3 -DEX and then escalated oxidative stresses by triggering a HCO 3 - -indispensable Mn-based Fenton-like reaction and breaking Ca 2+ ion homeostasis to cause oxidative stress in cells and calcification. The released anti-inflammatory and antitumor drug, DEX, could alleviate the inflammatory environment. The investigations in vitro and in vivo demonstrated that the synergistic oncotherapy could effectively inhibit the growth of subcutaneous tumors and orthotopic liver tumors. Notably, normal cells showed greater tolerance of the synergistic influences. Conclusion: As an ion drug, Mn:CaCO 3 -DEX is an excellent potential diagnostic agent for precise orthotopic tumor management by the generation in situ of toxic ion and drug pools in the environment of tumor region, with synergistic effects of enhanced chemodynamic therapy, calcification, and anti-inflammation effects., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Purpose: Proton pump inhibitors (PPIs) are used for the treatment of acid-related disorders. Demands for enhanced stability and faster onset led to the development of AD-206, a fixed-dose combination of a PPI (esomeprazole) with an antacid salt (calcium carbonate). This study compared the pharmacokinetics (PKs) and pharmacodynamics (PDs) of AD-206 (Addpharma) with conventional esomeprazole (Nexium ® , AstraZeneca)., Materials and Methods: A randomized, open-label, two-treatment, two-sequence crossover study was conducted with 2 different doses of esomeprazole at 20 and 40 mg with a fixed calcium carbonate dose of 600 mg in AD-206. Forty-four subjects were included in each dose group and randomly received either AD-206 or the conventional esomeprazole for 7 consecutive days in each period. After a single- and multiple-dose, blood samples for the PK analysis were analyzed, and 24-hour intragastric pH monitoring was conducted., Results: The systemic exposure of esomeprazole after a multiple-dose of AD-206 was similar to that of the conventional esomeprazole in both doses, but the time to reach the peak concentration was faster in AD-206. The percentage decrease from baseline in the integrated gastric acidity for a 24-hour interval after the dose was not significantly different between the AD-206 and the conventional esomeprazole after a single- and multiple-dose for both doses, and the time to reach pH 4 was faster for AD-206., Conclusion: AD-206 showed a similar systemic exposure and suppression of gastric acid secretion after a multiple-dose compared to the conventional esomeprazole., Competing Interests: The authors report no conflicts of interest in this work., (© 2021 Bae et al.)

Background: Rhizoma drynariae, a traditional Chinese herb, is commonly used in treatment of bone healing in osteoporotic fractures. However, whether the Rhizoma drynariae total flavonoids (RDTF) can promote the absorption of calcium and enhance the bone formation is unclear. The aim of the present study was to investigate the preventive effects of RDTF combined with calcium carbonate (CaCO 3 ) on estrogen deficiency-induced bone loss., Methods: Three-month-old Sprague-Dawley rats were ovariectomized (OVX) and then treated with CaCO 3, RDTF, and their admixtures for ten weeks, respectively. The bone trabecular microstructure, bone histopathological examination, and serum biomarkers of bone formation and resorption were determined in the rat femur tissue. The contents of osteoprotegerin (OPG), receptor activator of the NF-κB (RANK), and its ligand (RANKL) in marrow were analyzed by ELISA, and the protein expressions of Wnt3a, β-catenin, and phosphorylated β-catenin (p-β-catenin) were analyzed by Western blot. Statistical analysis was conducted by using one-way analysis of variance (ANOVA) followed by LSD post hoc analysis or independent samples t test using the scientific statistic software SPSS version 20.0 RESULTS: RDTF combined with CaCO 3 could promote osteosis and ameliorate bone loss to improve the repair of cracked bone trabeculae of OVX rats. Furthermore, RDTF combined with CaCO 3 also could prevent OVX-induced decrease in collagen fibers in the femoral tissue of ovariectomized rats and promote the regeneration of new bone or cartilage tissue, while CaCO 3 supplementation promoted the increase in bone mineral content. Nevertheless, there was no difference in the expression of Wnt3a, β-catenin and p-β-catenin between osteopenic rats and RDTF treated rats, but RDTF combined with CaCO 3 could activate the Wnt3a/β-catenin pathway., Conclusions: RDTF combined with CaCO 3 could ameliorate estrogen deficiency-induced bone loss via the regulation of Wnt3a/β-catenin pathway., (© 2021. The Author(s).)

This study aimed to evaluate the effects of chicken eggshell powder rich in calcium and the inorganic form of calcium carbonate on osteoporotic bone structure using an animal model of ovariectomized rats. Animals were divided into four groups: sham-operated rats (SHAM group); ovariectomized rats untreated (OVX group); OVX rats treated with eggshell powder (Biomin H® OVX + ECa group; total Ca content 1.5%); and OVX rats receiving inorganic calcium carbonate (calcium carbonate precipitated, total Ca content 1.5%; OVX + ICa group) during 8 weeks. Ovariectomy increased total body weight, plasma alkaline phosphatase activity, cortical bone thickness, periosteal bone apposition, and considerably worsened the trabecular bone microarchitecture. Calcium supplementation in both OVX + ECa and OVX + ICa groups elevated blood supply in the cortical bone when compared to OVX rats. Treatment with eggshell powder, unlike the OVX + ICa group, significantly lowered bone resorption, increased plasma calcium level, relative volume of trabecular bone, and secondary osteon population density, which together contributes to the enhanced bone strength. In addition, sizes of Haversian canals and secondary osteons in OVX + ECa group reached the values of SHAM group. Our results suggest that chicken eggshell powder more effectively ameliorates bone loss in ovariectomized rats than precipitated calcium carbonate.

Introduction: Imperfect hemostasis after arteriovenous fistula (AVF) and arteriovenous graft (AVG) cannulation can cause a hematoma or pseudoaneurysm and leads to poor satisfaction. We hypothesized that a hydrogel-coated needle would effectively and rapidly stop bleeding after vascular cannulation in a rat AVF and AVG model., Method: A hydrogel comprised of sodium alginate (SA), hyaluronic acid (HA), and calcium carbonate was coated onto the surface of suture needles using a rotating system. The needles were observed using scanning electron microscopy (SEM) and immunofluorescence. Rat AVF with or without renal failure and AVG were punctured using bare and hydrogel-coated needles. The tissues were examined by histology., Result: The hydrogel was successfully coated onto the surface of 30 G needles and confirmed by SEM. Hydrogel-coated needles rapidly stopped bleeding after AVF and AVG cannulation in rat., Conclusion: In this preliminary animal research, hydrogel-coated needles can stop AVF and AVG puncture-site bleeding; but additional clinical studies are needed to justify whether it is still effective in clinical., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

The nutritional values of limestone, oyster shell and extruded eggshells were evaluated using different methods. In total, 120 ready-to-lay pullets, 18-week-old ISA Brown were distributed into six dietary groups, namely D 1 (4% limestone), D 2 (8% limestone), D 3 (4% oyster shell), D 4 (8% oyster shell), D 5 (4% eggshell) and D 6 (8% eggshell), to assess the effect of calcium sources on egg production, egg quality, dry matter and cholesterol content of the egg. Kitchen-extruded eggshell contained 98.52, 4.24, 29.75 and 14.82% DM, CP, Ca and P, whereas hatchery-extruded eggshell contained 99.20, 13.80, 25.53 and 13.87% DM, CP, Ca and P, respectively. Limestone and Oyster shells contained 99.60 and 99.51% DM, and 37.12 and 35.20% Ca, respectively. Body weight, egg, hen day and egg mass production, and FCR did not differ among diets (p > .05). Egg production tended to increase with the increase of hen-housed egg production (p < .001) in D 6 , followed by D 2 , D 5 , D 3 , D 4 and D 1 , respectively. The lowest production cost and the highest net profit were observed in D 6 , followed by D 2 , D 4 , D 5 , D 1 and D 3 , respectively. Diet with 8% Ca sources performed better than the diets with 4% Ca sources in terms of egg quality and dry matter content, where D 6 was comparable to D 2 or D 4 . The weight of egg, albumen, yolk, eggshell, dry yolk and yolk-albumen ratio increased, while dry albumen and eggshell weight, eggshell strength and thickness, Haugh unit, yolk index and egg-specific gravity decreased with the increase in bird's age. The cholesterol content of yolk was statistically similar among diets. Therefore, no adverse effect of calcium sources on the production of laying hen was observed. Of these, extruded eggshell especially the 8% extruded eggshell may be beneficial to use in the diet of laying hen for producing a quality, safe and profitable egg., (© 2021 The Authors Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Malaria is still a global health problem. Plasmodium is a single-cell protozoan parasite that causes malaria and is transmitted to humans through the female Anopheles mosquito. The previous study showed that Sonchus arvensis L. callus has antiplasmodial activity. Several treatments are needed for callus quality improvement for antimalarial compound production. This study aimed to examine the effect of dolomite [CaMg(CO3)2] on growth (morpho-anatomical structure and biomass), secondary metabolite production, and in vitro antiplasmodial activity of S. arvensis L. callus. In this study, leaf explants were grown in Murashige and Skoog medium with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D, one mg/L) and 6-benzyl amino purine (BAP, 0.5 mg/L) with dolomite (50, 75, 100, 150, and 200 mg/L). The 21 days callus ethanolic and methanolic extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). The antiplasmodial test was performed on a blood culture infected with Plasmodium falciparum strain 3D7 using the Rieckmann method. The results showed that dolomite significantly affected callus growth, metabolite profile, and in vitro antiplasmodial activity. Dolomite (150 mg/L) showed the highest biomass (0.590 ± 0.136 g fresh weight and 0.074 ± 0.008 g dry weight). GC-MS analysis detected four compounds from callus ethanolic extract. Pelargonic acid, decanoic acid, and hexadecanoic acid were major compounds. One new terpenoid compound is based on TLC analysis. S. arvensis L. callus has antiplasmodial activity with the IC50 value of 5.037 μg/mL. It was three times lower than leaf methanolic extract and five times lower than leaf ethanolic extract., Competing Interests: The authors have declared that no competing interests exist.

Calcium carbonate is used as bone-filling material due to its good biocompatibility, bioactivity, and bioabsorbability, but the prevalence of infectious complications associated with calcium carbonate has created a persisting challenge in the treatment of bone defect. Therefore, this greatly necessitate the need to endow calcium carbonate with antibacterial properties. In this study, calcium carbonate powders loaded with silver nanoparticles (Ag-CaCO 3 ) were prepared in attempt to serve as a novel antibacterial inorganic filler material. This objective was achieved using ultrasonic spray-pyrolysis (USSP) route to produce Ag-CaCO 3 with 1, 5 and 10 mol% silver. The size of silver nanoparticles on CaCO 3 microspheres could be regulated by adjusting silver concentration to facilitate effective release of Ag + ions. This was demonstrated in Ag-CaCO 3 (1), where the lowest silver content at 1 mol% achieved the highest Ag + ions release over 28 days. This in turn gave rise to effective antibacterial efficiency against Staphylococcus aureus and Escherichia coli. Furthermore, CaCO 3 (1) could also support osteoblast-like cells (MG-63) at a cell viability of 80%. Overall, this work extends the capabilities in employing USSP to produce inorganic filler materials with sustained antibacterial properties, bringing one step closer to the development of antibacterial products., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Biomineralization is the process by which living organisms generate organized mineral crystals. In human cells, this phenomenon culminates with the formation of hydroxyapatite, which is a naturally occurring mineral form of calcium apatite. The mechanism that explains the genesis within the cell and the propagation of the mineral in the extracellular matrix still remains largely unexplained, and its characterization is highly controversial, especially in humans. In fact, up to now, biomineralization core knowledge has been provided by investigations on the advanced phases of this process. In this study, we characterize the contents of calcium depositions in human bone mesenchymal stem cells exposed to an osteogenic cocktail for 4 and 10 days using synchrotron-based cryo-soft-X-ray tomography and cryo-XANES microscopy. The reported results suggest crystalline calcite as a precursor of hydroxyapatite depositions within the cells in the biomineralization process. In particular, both calcite and hydroxyapatite were detected within the cell during the early phase of osteogenic differentiation. This striking finding may redefine most of the biomineralization models published so far, taking into account that they have been formulated using murine samples while studies in human cell lines are still scarce.

The development of heterogeneous drug delivery systems leads to innovative strategies for targeted therapy of common pathologies, such as cancer, immunological and neurological disorders. Nowadays, it is possible to choose among a great variety of nanoparticles on the basis of the needs they have to satisfy. However, a candidate for the treatment of cardiovascular pathologies is still missing. In this context, a targeted therapy implies the conceptualization of nanoparticles that take active part in the treatment of vascular pathologies. The aim of this work was to provide a method to produce multi-layered calcium carbonate (CaCO 3 ) nanoparticles encapsulating a model protein, bovine serum albumin, with model antibodies on their surface. CaCO 3 nanoparticles were produced by the combination of complex coacervation and mineralization and were engineered using layer-by-layer technique with a polysaccharide, dextran sulfate, and a homo-poly-amino acid, poly-L-arginine. Morphology, biocompatibility, cellular uptake, influence on cell expression of the inflammatory marker matrix metalloproteinase-9, and hemocompatibility of the nanoparticles were studied. The presence of the dextran/poly-L-arginine layers did not negatively affect the nanoparticle overall characteristics and they did not trigger proinflammatory response in vitro. Taking together all the obtained results, we consider the proposed CaCO 3 nanoparticles as a promising tool in cardiovascular field., (Copyright © 2021. Published by Elsevier B.V.)