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Purpose: To demonstrate a modified surgical approach for horizontal ridge augmentation that allows for safe manipulation and predictable management of the buccal plate and avoids creation of a secondary surgical site. Materials and Methods: This pilot randomized controlled clinical trial included 24 patients who required horizontal alveolar ridge augmentation. Patients were assigned to one of the three groups: Group A was treated with the buccal plate repositioning (BPR) technique and grafted with silica calcium phosphate nanocomposite (SCPC) graft, group B was similarly managed and grafted using demineralized freeze-dried bone allograft (DFDBA), and group C was augmented using mandibular ramus autogenous bone block graft (ABBG). The primary outcome was the coronal crest width, which was measured at 6 months using CBCT. Results: The BPR technique resulted in horizontal augmentation with a mean of 4.30 ± 0.94 mm for group A, showing no significant difference from either group B (4.98 ± 1.13 mm) or group C (3.68 ± 0.27 mm). All augmented ridges allowed for successful implant placement with good primary stability. Conclusions: The BPR technique resulted in horizontal bone gain in extremely narrow alveolar ridges. It allowed for implant placement in a vascular cancellous bed protected by intact cortical plate. Different types of bone grafts, whether alloplast or allograft, resulted in successful augmentation comparable to that gained from autogenous block grafting. [ABSTRACT FROM AUTHOR]

The global diffusion of antibiotic resistance poses a severe threat to public health. Addressing antibiotic-resistant infections requires innovative approaches, such as antibacterial nanostructured surfaces (ANSs). These surfaces, featuring ordered arrays of nanostructures, exhibit the ability to kill bacteria upon contact. However, most currently developed ANSs utilize bioinert materials, lacking bioactivity crucial for promoting tissue regeneration, particularly in the context of bone infections. This study introduces ANSs composed of bioactive calcium phosphate nanocrystals. Two distinct ANSs were created through a biomineralization-inspired growth of amorphous calcium phosphate (ACP) precursors. The ANSs demonstrated efficient antibacterial properties against both Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) antibiotic resistant bacteria, with up to 75 % mortality in adhered bacteria after only 4 h of contact. Notably, the ANS featuring thinner and less oriented nano-needles exhibited superior efficacy attributed to simultaneous membrane rupturing and oxidative stress induction. Moreover, the ANSs facilitate the proliferation of mammalian cells, enhancing adhesion, spreading, and reducing oxidative stress. The ANSs displayed also significant bioactivity towards human mesenchymal stem cells, promoting colonization and inducing osteogenic differentiation. Specifically, the ANS with thicker and more ordered nano-needles demonstrated heightened effects. In conclusion, ANSs introduced in this work have the potential to serve as foundation for developing bone graft materials capable of eradicate site infections while concurrently stimulating bone regeneration. Nanostructured surfaces with antibacterial properties through a mechano-bactericidal mechanism have shown significant potential in fighting antibiotic resistance. However, these surfaces have not been fabricated with bioactive materials necessary for developing devices that are both antibacterial and able to stimulate tissue regeneration. This study demonstrates the feasibility of creating nanostructured surfaces of ordered calcium phosphate nano-needles through a biomineralization-inspired growth. These surfaces exhibit dual functionality, serving as effective bactericidal agents against Gram-negative and Gram-positive antibiotic-resistant bacteria while also promoting the proliferation of mammalian cells and inducing osteogenic differentiation of human mesenchymal stem cells. Consequently, this approach holds promise in the context of bone infections, introducing innovative nanostructured surfaces that could be utilized in the development of antimicrobial and osteogenic grafts. [Display omitted] [ABSTRACT FROM AUTHOR]

The cell (plasma) membrane is enriched with numerous receptors, ligands, enzymes, and phospholipids that play important roles in cell-cell and cell-extracellular matrix interactions governing, for instance, tissue development and repair. We previously showed that plasma membrane nanofragments (PMNFs) act as nucleation sites for bone formation in vivo , and induce in vitro mineralization within 1 day. In this study, we optimized the methods for generating, isolating, and applying PMNFs as a cell-free therapeutic to expedite bone defect repair. The PMNFs were isolated from different mouse cell lines (chondrocytes, osteoblasts, and fibroblasts), pre-conditioned, lyophilized, and subsequently transplanted into 2 mm critical-sized calvarial defects in mice (n = 75). The PMNFs from chondrocytes, following a 3-day pre-incubation, significantly accelerated bone repair within 2 weeks, through a coordinated attraction of macrophages, endothelial cells, and osteoblasts to the healing site. In vitro experiments confirmed that PMNFs enhanced cell adhesion. Comparison of the PMNF efficacy with phosphatidylserine, amorphous calcium phosphate (ACP), and living cells confirmed the unique ability of PMNFs to promote accelerated bone repair. Importantly, PMNFs promoted nearly complete integration of the regenerated bone with native tissue after 6 weeks (% non-integrated bone area = 15.02), contrasting with the partial integration (% non-integrated bone area = 56.10; p < 0.01, Student's test) with transplantation of ACP. Vickers microhardness tests demonstrated that the regenerated bone after 6 weeks (30.10 ± 1.75) exhibited hardness similar to native bone (31.07 ± 2.46). In conclusion, this is the first study to demonstrate that cell membrane can be a promising cell-free material with multifaceted biofunctional properties that promote accelerated bone repair. • For the first time, the cell (plasma) membrane is used as material for bone repair. • The plasma membrane from chondrocytes promoted rapid bone repair within 2 weeks, with complete integration of the newly formed bone with the surrounding native tissue. • The plasma membrane from chondrocytes presented multifaceted effects, strongly promoting the attraction of macrophages, endothelial cells and osteoblasts to the healing site. [Display omitted] [ABSTRACT FROM AUTHOR]

Objective: Unusual or unexpected effect of treatment Background: Infection control and reconstruction of bone and soft tissue are essential for treating infected nonunion. Continuous local antibiotic perfusion (CLAP) is a drug delivery system that continuously delivers antibiotics at the required concentration, area, and duration. This case report describes the instance of infected nonunion in which infection eradication and bone union were achieved using CLAP and synthetic bone grafting while retaining the implant. Case Report: The case was a 31-year-old woman with an infected nonunion. After she underwent osteosynthesis using nail for open fractures of tibia and fibula, bone union remained unachieved, and she exhibited skin defects and draining of pus. Following the removal of the infected granulation tissue from the bone defects, 2 bone marrow needles, serving as intramedullary antibiotic perfusion (iMAP) pins, were inserted into the medullary cavity tibia. A double-lumen tube was placed in the subcutaneous pocket as the intra-soft tissue antibiotic perfusion (iSAP) tube. No bone mobility was observed around the bone defect and nail, and replacement of the implant was not necessary. Beta-tricalcium phosphate was transplanted to the bone defect, and negative pressure wound therapy was applied. Gentamicin was injected continuously through iMAP and iSAP. Finally, the infection was eradicated, and cortical bone bridging was observed without additional surgery or adverse effects. Conclusions: CLAP emerges as a viable treatment option for infected nonunion, as it enables the delivery of antibiotics at a concentration sufficient for infection control while providing the surgeon with flexibility to design the area, dosage, and duration of antibiotic delivery. [ABSTRACT FROM AUTHOR]

Octacalcium phosphate (OCP), an inorganic compound with a layered structure that can incorporate various carboxylic acids, exhibits fluorescence when aromatic carboxylate ions are present in the inter- layers. However, the incorporation of carboxylate ions into OCP involves molecular selectivity, and the synthesis of novel OCP materials with incorporated terephthalate ion derivatives is particularly challen- ging. In this study, we incorporated 4-(carboxymethyl)benzoate and 1,4-phenylenediacetate ions into OCP for the first time and investigated the resulting fluorescence properties. The relationship between the (100) interplanar spacing and size of the incorporated dicarboxylate ions revealed that 4-(carboxy- methyl)benzoate ions have a relaxed structure in the OCP interlayers, whereas the structure of the 1,4- phenylenediacetate ions is elongated by approximately 10% relative to that of the stable conformation. OCP with incorporated 1,4-phenylenediacetate ions showed blue fluorescence at 286 nm under 254 nm excitation. In contrast, distinct from previously reported fluorescent OCPs, OCP with incorporated 4-(carboxymethyl)benzoate ions exhibited two-colour fluorescence, with pink emission under 254 nm excitation and blue emission under 312 and 365 nm excitation. This OCP material exhibiting fluorescence at two wavelengths in the visible-light range offers new possibilities for practical applications. In particular, these unique fluorescence characteristics combined with the excellent biological properties of OCP can be exploited to develop novel biofriendly fluorescent probes. These findings contribute to an improved understanding of fundamental calcium phosphate chemistry and should encourage further research on functional OCP materials. [ABSTRACT FROM AUTHOR]

The development of synthetic bone substitutes that equal or exceed the efficacy of autologous graft remains challenging. In this study, a rat calvarial defect model was used as a reference to investigate the influence of composition and architecture of 3D-printed cement, with or without bioactives, on tissue regeneration. Printable cement pastes were formulated by combining hyaluronic acid and cement precursors. Cementitious scaffolds were printed with 3 different patterns. After 7 weeks of implantation with or without bone marrow, multiparametric qualitative and quantitative assessments were performed using µCT, SEM, and histology. None of the set-up strategies was as efficient as autologous cancellous bone graft to repair calvarial defects. Nonetheless, the presence of scaffold improved the skull vault closure, particularly when the scaffold was soaked in total bone marrow before implantation. No significant effect of scaffold macro-architecture was observed on tissue mineralization. Magnesium phosphate-based scaffolds (MgP) seemed to induce higher bone formation than their calcium-phosphate-based counterparts. They also displayed a quicker biodegradation and sparse remaining material was found after 7 weeks of implantation. Although further improvements are required to reach clinical settings, this study demonstrated the potential of organo-mineral cements for bone regeneration and highlighted the peculiar properties of MgP-based cements. [ABSTRACT FROM AUTHOR]

The interconnected structures in a 3D scaffold allows the movement of cells and nutrients. Therefore, this study aimed to investigate the in-vivo bioactivity of 3D-printed β-tricalcium phosphate (β-TCP) and hydroxyapatite (HAP) scaffolds that replicate biological bone. This study included 24-week-old male New Zealand white rabbits. A cylindrical bone defect with a diameter of 4.5 mm and a depth of 8 mm was created in the lateral aspect of the distal femur. A 3D-printed scaffold was implanted in the right femur (experimental side), whereas the left femur was kept free of implantation (control side). Micro-CT analysis and histological observations of the bone defect site were conducted at 4, 8, and 12 weeks postoperatively to track the bone repair progress. No evidence of new bone tissue formation was found in the medullary cavity of the bone defect on the control side. In contrast, on the experimental side, the 3D scaffold demonstrated sufficient bioactivity, leading to the growth of new bone tissue. Over time, new bone tissue gradually extended from the periphery toward the center, a phenomenon evident in both micro-CT images and biopsy staining. In the current study, we observed that the cells involved in bone metabolism adhered, spread, and proliferated on our newly designed 3D-printed scaffold with a bone microstructure. Therefore, it is suggested that this scaffold has sufficient bioactivity to induce new bone formation and could be expected to be a more useful artificial bone than the existing version. [ABSTRACT FROM AUTHOR]

The osteoinductivity of 3D printed calcium phosphate (CaP) ceramics has a large gap compared with those prepared by conventional foaming methods, and improving the osteoinductivity of 3D printing CaP ceramics is crucial for successful application in bone regeneration. Pore architecture plays a critical role in osteoinductivity. In this study, CaP ceramics with a hexagonal close-packed (HCP) spherical pore structure were successfully fabricated using DLP printing technology. Additionally, octahedral (Octahedral), diamond (Diamond), and helical (Gyroid) structures were constructed with similar porosity and macropore diameter. CaP ceramics with the HCP structure exhibited higher compression strength (8.39 ± 1.82 MPa) and lower permeability (6.41 × 10−11 m2) compared to the Octahedral, Diamond, and Gyroid structures. In vitro cellular responses indicated that the macropore architecture strongly influenced the local growth rate of osteoblast-formed cell tissue; cells grew uniformly and formed circular rings in the HCP group. Furthermore, the HCP group promoted the expression of osteogenic genes and proteins more effectively than the other three groups. The outstanding osteoinductivity of the HCP group was confirmed in canine intramuscular implantation studies, where the new bone area reached up to 8.02 ± 1.94 % after a 10-week implantation. Additionally, the HCP group showed effective bone regeneration in repairing femoral condyle defects. Therefore, our findings suggest that 3D printed CaP bioceramics with an HCP structure promote osteoinductivity and can be considered as candidates for personalized precise treatment of bone defects in clinical applications. 1. 3D printing BCP ceramics with high osteoinductivity were constructed through pore architecture optimization. 2. BCP ceramics with HCP structure exhibited relatively higher mechanical strength and lower permeability than those with Octahedral, Diamond and Gyroid structures. 3. BCP ceramics with HCP structure could promote the osteogenic differentiation of MC3T3-E1, and showed the superior in-vivo osteoinductivity and bone regeneration comparing with the other structures. [Display omitted] [ABSTRACT FROM AUTHOR]

Ti-6Al-4V alloy due to high mechanical properties and high corrosion resistance is widely used in the manufacture of biomedical devices, including hip articulations, screws and dental implants. For proper implant performance in the long run, a rapid reaction between the bone and implant should be performed, which depends on the surface properties of the layer doped on the surface of the implant. The surface coating is therefore considered to be the underlying factor in the attenuation of such occurrences. This research aims to assess the modified surface of Ti-6Al-4V by the mixed electric discharge (EDM) process of β-tricalcium phosphate powder to detect potential bioimplants. One of the features of this coating process is the location of the base titanium layer containing β-tricalcium phosphate, thereby improving the substrate properties. For investigating the surface morphology, distribution and dispersion of elements on the modified surface, field emission scanning electron microscope (FE-SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) tests were used. Morphological features have shown that porous surface topography just like natural bone is coated on the surface of Ti-6Al-4V alloy using the AM-EDM process. EDS and XRD examinations showed the coated layer compositions from Ti kα, V, Al, Ca and P and also formation of the biocompatible phases such as Ca 2 P 2 O 7 andCa OH 2 on the surface of Ti-6Al-4V, which caused the better biocompatibility of the alloy, creation of an antibacterial agent for periodical injuries and also improvement of the bone formation on the alloy surface. The results also showed that the size of the resin thickness was 35 micrometers, which contained nanoparticles of tricalcium phosphate, as well as an excellent metallurgical substrate with a strong bond between the substrate and the coating. In this research, the effects of input parameters, such as spark energy and powder concentration on output parameters, including material removal rate, surface roughness and surface hardness, were studied. The results showed that this method has a positive effect on the reduction in the material removal rate, roughness and hardness of the surface of the workpiece. Due to the dispersion of β-tricalcium phosphate particles, the surface roughness diminishes during the electric discharge process. Also, the highest material removal rate occurred in 21 A, the pulse duration of 50 μs and the concentration of 8 g/L, and minimal surface roughness occurred in 6 A, the pulse duration of 100 μs and the concentration of 4 g/L. The hardness of the surface deposited with β-tricalcium phosphate powder is 348 VH, which is 1.75 times more than the original surface. The reason is that the hard oxide is deposited on the surface of the workpiece. [ABSTRACT FROM AUTHOR]

Objectives: The main purpose of this study was to compare the remineralizing effects of casein phosphopeptide amorphous calcium phosphate fluoride (CPPACPF) and tricalcium phosphate (TCP) on artificially induced enamel white spot lesions (WSLs). Materials and Methods: In this in vitro study, 45 sound extracted premolars were immersed in a demineralizing solution (pH=4.5) for 96 hours, and were randomly divided into 3 groups of TCP, MI Paste Plus, and control. They were exposed to the remineralizing agents for 5 minutes once a day for 30 days. After mounting the teeth in resin blocks and polishing, they underwent a microhardness test at 3 different depths from the enamel surface. Data were analyzed by Prism software, two-way ANOVA, and Tukey's test (α=0.05). Results: The volume percentage of mineral content (VPM) was significantly different among the three groups at 30-, 60- and 90µm depths (P<0.0001). At 30µm depth, CPP-ACPF was significantly more effective than TCP (P<0.0001). At 60- and 90µm depths, there was no significant difference between CPP-ACPF and TCP (P>0.05). Conclusion: Both CPP-ACPF and TCP had significant efficacy for remineralization of artificially induced enamel WSLs under in vitro conditions. [ABSTRACT FROM AUTHOR]

Strontium is known for enhancing bone metabolism, osteoblast proliferation, and tissue regeneration. This systematic review aimed to investigate the biological effects of strontium-doped calcium phosphate biomaterials for bone therapy. A literature search up to May 2024 across Web of Science, PubMed, and Scopus retrieved 759 entries, with 42 articles meeting the selection criteria. The studies provided data on material types, strontium incorporation and release, and in vivo and in vitro evidence. Strontium-doped calcium phosphate biomaterials were produced via chemical synthesis and deposited on various substrates, with characterization techniques confirming successful strontium incorporation. Appropriate concentrations of strontium were non-cytotoxic, stimulating cell proliferation, adhesion, and osteogenic factor production through key signaling pathways like Wnt/β-catenin, BMP-2, Runx2, and ERK. In vivo studies identified novel bone formation, angiogenesis, and inhibition of bone resorption. These findings support the safety and efficacy of strontium-doped calcium phosphates, although the optimal strontium concentration for desired effects is still undetermined. Future research should focus on optimizing strontium release kinetics and elucidating molecular mechanisms to enhance clinical applications of these biomaterials in bone tissue engineering. [ABSTRACT FROM AUTHOR]

The strategies used to associate peptide arginylglycylaspartic acid (RGD) with calcium phosphate grafts to enhance cell–biomaterial interactions have been controversial in the literature. Several works have demonstrated that RGD-functionalized hydroxyapatite (HA) surfaces improve cell adhesion, whereas others claim that RGD-loaded HA has an inhibitory effect when serum is present in the biological medium. To investigate such contradictory results, we associated RGD with the HA surface using physical adsorption and chemical bonding methods and evaluated the cell adhesion and spreading in pre-osteoblasts culture with and without fetal bovine serum (FBS). The effect of functionalization methods on the physicochemical characteristics of both surfaces was analyzed using multiscale techniques. Adsorption assays of serum allowed us to estimate the impact of the association method on the HA surface's reactivity. Physically adsorbed RGD did not increase the number of adhered cells due to the weak interactions between the peptide and the surface. Although chemical binding stabilizes RGD on the HA, the functionalization procedure covered the surface with molecules such as (3-aminopropyl)triethoxysilane (APTEs) and carbodiimide, changing the surface's chemical activity. Serum protein adsorption decreased by 90%, revealing a significant reduction in the surface interactions with molecules of the biological medium. The present study's findings showed that the RGD's physical association with HA did not improve cell adhesion and that this phenomenon is highly dependent on the presence of serum proteins. [ABSTRACT FROM AUTHOR]

Doping of brushite cements with metal ions can entail many positive effects on biological and physicochemical properties. Cu2+ ions are known to exhibit antibacterial properties and can additionally have different positive effects on cells as trace elements, whereas high Cu2+ concentrations are cytotoxic. For therapeutical applications of bone cement, a combination of good biocompatibility and sufficient mechanical properties is required. Therefore, the aim of this study was to investigate different physicochemical and biological aspects, relevant for application, of a brushite cement with Cu2+‐doped β‐tricalcium phosphate, monocalcium phosphate monohydrate and phytic acid as setting retarder. Additionally, the ion release was compared with a cement with citric acid as setting retarder. The investigated cements showed good injectability coefficients, as well as compressive strength values sufficient for application. Furthermore, no antibacterial effects were detected irrespective of the Cu2+ concentration or the bacterial strain. The cell experiments with eluate samples showed that the viability of MC3T3‐E1 cells tended to decrease with increasing Cu2+ concentration in the cement. It is suggested that these biological responses are caused by the difference in the Cu2+ release from the hardened cement depending on the solvent medium. Furthermore, the cements showed a steady release of Cu2+ ions to a lesser extent in comparison with a cement with citric acid as setting retarder, where a burst release of Cu2+ was observed. In conclusion, despite the anticipated antibacterial effect of Cu2+‐doped cements was lacking and mammalian cell viability was slightly affected, Cu2+‐concentrations maintained the physicochemical properties as well as the compressive strength of cements and the slow ion release from cements produced with phytic acid is considered advantageous compared to citric acid‐based formulations. [ABSTRACT FROM AUTHOR]

In recent years, a growing demand for biomaterials has been observed, particularly for applications in bone regenerative medicine. Bone tissue engineering (BTE) aims to develop innovative materials and strategies for repairing and regenerating bone defects and injuries. Polysaccharides, due to their biocompatibility, biodegradability as well as bioactivity, have emerged as promising candidates for scaffolds or composite systems in BTE. Polymers combined with bioactive ceramics can support osteointegration. Calcium phosphate (CaP) ceramics can be a broad choice as an inorganic phase that stimulates the formation of new apatite layers. This review provides a comprehensive analysis of composite systems based on selected polysaccharides used in bone tissue engineering, highlighting their synthesis, properties and applications. Moreover, the applicability of the produced biocomposites has been analyzed, as well as new trends in modifying biomaterials and endowing them with new functionalizations. The effects of these composites on the mechanical properties, biocompatibility and osteoconductivity were critically analyzed. This article summarizes the latest manufacturing methods as well as new developments in polysaccharide-based biomaterials for bone and cartilage regeneration applications. [ABSTRACT FROM AUTHOR]

65Zn, a fission product found in cooling water reactors, poses significant environmental risks due to its toxicity. This study explores the use of Ca–Fe2+ phosphate (SB1) and Ca–Fe3+ phosphate (SB2) as sorbents for Zn(II), prepared via the wet chemical method. The Zn(II) solution, spiked with 65Zn radionuclides, was analyzed radiometrically. Optimal sorption conditions were determined to be pH 4.5, a contact time of 24 h, and a sorbate volume to sorbent mass ratio of 1:10 at 20 °C. The Langmuir isotherm model best fit the adsorption data, indicating monolayer adsorption capacities of 0.574 mmol g−1 for SB1 and 0.621 mmol g−1 for SB2. Sorption kinetics followed a quasi-nth-order model. Furthermore, 0.1 M FeCl3 effectively desorbed 99% of Zn(II) from both sorbents. The sorption process was found to be spontaneous and endothermic. These findings suggest that SB1 and SB2 have potential applications in recycling Zn(II) from the black mass of expired batteries. [ABSTRACT FROM AUTHOR]

Visceral Leishmaniasis is a serious public health problem caused by Leishmania species parasites. Approximately 500 thousand people get Visceral Leishmaniasis (VL) every year. An effective and reliable vaccine against the disease has still not been formulated. Choosing the right adjuvant is important to increase immunogenicity in vaccines prepared with total antigens. In this study, we investigate the ideal adjuvant for use in vaccine formulations against VL. For this purpose, Leishmania antigens (FTLA) obtained from L. infantum parasites by the freeze-thaw method and three different adjuvants (alum-saponin and calcium phosphate) were used. The effectiveness of the formulations was investigated in vitro by cell viability analysis and determination of nitric oxide and cytokine production abilities in J774 macrophage cells. According to the study results, it was determined that formulations prepared with calcium phosphate produced 72% more NO and approximately 7.2 times more IL-12 cytokine. The results obtained showed that calcium phosphate salts can be used as ideal adjuvants in vaccine research against leishmaniasis. [ABSTRACT FROM AUTHOR]

To address the insufficiencies in the systemic research of calcium phosphate/alginate (ALG) microspheres for multi-drug delivery and bone formation, this study investigated the multi-drug release kinetics and osteogenic behaviors of β-tricalcium phosphate/ALG microspheres. The results showed that different loaded drugs exhibited an early burst release phenomenon, and the drug loading capacity decreased as the microsphere particle size decreased. In vitro cell proliferation and dead/live staining demonstrated that the microspheres had excellent cytocompatibility, and in vivo experiments demonstrated the microspheres' exceptional ability to enhance bone regeneration. [ABSTRACT FROM AUTHOR]

Effective healing and regeneration of various bone defects is still a major challenge and concern in modern medicine. Calcium phosphates have emerged as extensively studied bone substitute materials due to their structural and chemical resemblance to the mineral phase of bone, along with their versatile properties. Calcium phosphates present promising biological characteristics that make them suitable for bone substitution, but a critical limitation lies in their low osteoinductivity. To supplement these materials with properties that promote bone regeneration, prevent infections, and cure bone diseases locally, calcium phosphates can be biologically and therapeutically modified. A promising approach involves combining calcium phosphates with drug-containing liposomes, renowned for their high biocompatibility and ability to provide controlled and sustained drug delivery. Surprisingly, there is a lack of research focused on liposome-calcium phosphate composites, where liposomes are dispersed within a calcium phosphate matrix. This raises the question of why such studies are limited. In order to provide a comprehensive overview of existing liposome and calcium phosphate composites as bioactive substance delivery systems, the authors review the literature exploring the interactions between calcium phosphates and liposomes. Additionally, it seeks to identify potential interactions between calcium ions and liposomes, which may impact the feasibility of developing liposome-containing calcium phosphate composite materials. Liposome capacity to protect bioactive compounds and facilitate localized treatment can be particularly valuable in scenarios involving bone regeneration, infection prevention, and the management of bone diseases. This review explores the implications of liposomes and calcium phosphate material containing liposomes on drug delivery, bioavailability, and stability, offering insights into their advantages. [ABSTRACT FROM AUTHOR]

The aim of this study was to prepare and characterize the calcium phosphates modified by different amount of Na+, Cu2+, Zn2+ and CO32−, and to investigate their activity in model solution (at pH = 7.45 and 37 °C) and antibacterial properties against Streptococcus pyogenes. According to XRD and FTIR spectroscopy data the apatite-related phases with partial substitution РО43− → СО32− (B-type) have been prepared. Presence of sodium and carbonate ions led to increase of solubility in model solution during the first 48 h, while modification with both Cu2+ and Zn2+ cations (up to 0.6 wt%) significantly improved antimicrobial properties against Streptococcus pyogenes. [ABSTRACT FROM AUTHOR]

An association of eighteen coprolites (specimens 01–18) and one isolated coprolite (specimen 209,210) were found in a vertebrate fossil-rich paleosol at the Gratkorn site (south-eastern Austria; late Middle Miocene). The specimens consist mostly of calcium phosphate (apatite) and a matrix formed by microglobules. Coprolites 01–18 show cylindrical and spherical morphologies and are considerably smaller than the tube-shaped specimen 209,210, in which no inclusions were observed. In contrast, coprolites 01–18 contain numerous, highly altered bone fragments (sub-mm-sized long bones and several mm-sized trabecular bone remains) as well as hair imprints, plant detritus and palynomorphs. Based on composition, morphology, size, microstructure, and inclusions, and considering the body fossil record of this site, we assume the hyaenid Protictitherium and the barbourofelid Albanosmilus, as producers of coprolites 01–18 and 209,210, respectively. The preserved bone remains in specimens 01–18 suggest that Protictitherium fed on small vertebrates, but possibly also cracked bones of medium-sized animals. The hair imprints found were either from the hyaenid itself or its prey, while the plant material was probably ingested accidentally. The lack of inclusions in specimen 209,210 is related to the presumably hypercarnivorous diet of Albanosmilus, which was certainly the apex predator in this biome. [ABSTRACT FROM AUTHOR]

Re-assembled casein micelles (rCMs), were formulated in the 1970s as a model system to understand native casein micelles (nCMs) in milk. These early works allowed an understanding of the critical factors involved in the formation of rCMs, such as minerals (citrate, phosphate, and calcium), casein type (αs-, β-, and κ-casein) and the extent of their phosphorylation. rCMs were also used to understand the effect of treatments such as ethanol, high hydrostatic pressure and heating on the stability and integrity of the micelles. More recently, the applications of rCMs have been investigated, these include their use as a nanocarrier of bioactive molecules and as electrode-bound substrates to monitor chymosin activity by electrochemistry, to cite a few. Moreover, the potential to use rCMs in both food and non-food applications remains to be fully exploited. The advantage of choosing rCMs over nCMs as an encapsulant and a lucrative food ingredient is due to their more efficient preparation and being free from impurities. In this review, we report on the formulation of rCMs, their physico-chemical properties and their behavior under different physico-chemical treatments, along with the applications and challenges of rCMs in food systems and their industrial production as a dairy ingredient. [ABSTRACT FROM AUTHOR]

Dental enamel is a mineralized extracellular matrix, and enamel defect is a common oral disease. However, the self‐repair capacity of enamel is limited due to the absence of cellular components and organic matter. Efficacy of biomimetic enamel mineralization using calcium phosphate ion clusters (CPICs), is an effective method to compensate for the limited self‐healing ability of fully developed enamel. Preparing and stabilizing CPICs presents a significant challenge, as the addition of certain stabilizers can diminish the mechanical properties or biosafety of mineralized enamel. To efficiently and safely repair enamel damage, this study quickly prepared CPICs without stabilizers using the atomization method. The formed CPICs were evenly distributed on the enamel surface, prompting directional growth and transformation of hydroxyapatite (HA) crystals. The study revealed that the mended enamel displayed comparable morphology, chemical composition, hardness, and mechanical properties to those of the original enamel. The approach of repairing dental enamel by utilizing ultrasonic nebulization of CPICs is highly efficient and safe, therefore indicating great promise. [ABSTRACT FROM AUTHOR]

Allogeneic bone grafts are used to treat bone defects in orthopedic surgery, but the osteogenic potential of artificial bones remains a challenge. In this study, we developed a β-tricalcium phosphate (β-TCP) formulation containing MgO, ZnO, SrO, and SiO2 and compared its bone-forming ability with that of β-TCP without biological elements. We prepared β-TCP discs with 60% porosity containing 1.0 wt% of these biological elements. β-TCP scaffolds were loaded with bone marrow-derived mesenchymal stem cells (BMSC) from 7-week-old male rats and cultured for 2 weeks. ALP activity and mRNA expression of osteogenic markers were evaluated. In addition, scaffolds were implanted subcutaneously in rats and analyzed after 7 weeks. In vitro, the MgO group showed lower Ca concentrations and higher osteogenic marker expression compared to controls. In vivo, the MgO group showed higher ALP activity compared to controls, and RT-qPCR analysis showed significant expression of BMP2 and VEGF. Histopathology, fluorescent immunostaining, and micro-CT also showed relatively better bone formation in the MgO group. β-TCP with MgO may enhance bone morphology in vitro and in vivo and improve the prognosis of patients with substantial and refractory bone defects. [ABSTRACT FROM AUTHOR]

Beta-tricalcium phosphate (β-TCP) scaffolds manufactured through the foam replication method are widely employed in bone tissue regeneration. The mechanical strength of these scaffolds is a significant challenge, partly due to the rheological properties of the original suspension. Various strategies have been explored to enhance the mechanical properties. In this research, β-TCP scaffolds containing varying concentrations (0.25–1.00 wt%) of multi-walled carbon nanotubes (MWCNT) were developed. The findings indicate that the addition of MWCNTs led to a concentration-dependent improvement in the viscosity of β-TCP suspensions. All the prepared slurries exhibited viscoelastic behavior, with the storage modulus surpassing the loss modulus. The three time interval tests revealed that MWCNT-incorporated β-TCP suspensions exhibited faster structural recovery compared to pure β-TCP slurries. Introducing MWCNT modified compressive strength, and the optimal improvement was obtained using 0.75 wt% MWCNT. The in vitro degradation of β-TCP was also reduced by incorporating MWCNT. While the inclusion of carbon nanotubes had a marginal negative impact on the viability and attachment of MC3T3-E1 cells, the number of viable cells remained above 70% of the control group. Additionally, the results demonstrated that the scaffold increased the expression level of osteocalcin, osteoponthin, and alkaline phosphatase genes of adiposed-derived stem cells; however, higher levels of gene expersion were obtained by using MWCNT. The suitability of MWCNT-modified β-TCP suspensions for the foam replication method can be assessed by evaluating their rheological behavior, aiding in determining the critical additive concentration necessary for a successful coating process. [ABSTRACT FROM AUTHOR]

Dental caries is a worldwide public healthcare concern, and is closely related to the acidic environment that caused by bacterial decomposition of food. In this study, a two-step ion exchange liquid-phase stripping method was applied to strip out vermiculite (VMT) nanosheets, then amorphous calcium phosphate (ACP) and dextran were inserted between the VMT nanosheets interlayer to obtain a composite two-dimension nanosheets (VMT/ACP/Dextran). VMT/ACP/Dextran composite nanosheets exhibited excellent biocompatibility and could provide exogenous Ca2+and PO43− from ACP, provide SiO44−, Mg2+, Fe2+ and obtain buffering pH and antibacterial properties from VMT, as well as improve suspension stability and targeting Streptococcus mutans through glucan. The in vitro study showed that the composite materials could promote the mineralization and sealing of dentin tubules by releasing active ions, buffer pH 4.5 (a value close to the pH in the dental plaque environment) to pH 6.6–7.1 (values close to the pH in human saliva) through ion exchange, and exert antibacterial effects by targeting Streptococcus mutans and exerting oxidase like and peroxidase like activities to produce reactive oxygen species (ROS). The in vivo animal study showed that daily cleaning teeth using VMT/ACP/Dextran composite nanosheets could effectively reduce the incidence rate and severity of dental caries in rats. Taking together, the developed VMT/ACP/Dextran composite nanosheets, which integrated the excellent properties of VMT, ACP and dextran, can effectively prevent dental caries through a combination of factors such as buffering acids, antibacterial properties, and promoting calcification, and may be used as an active ingredient for daily oral hygiene or filling materials to prevent and treat dental caries. [ABSTRACT FROM AUTHOR]

Passive radiative cooling materials are widely recognized as attractive innovations for reducing emissions and expanding life-saving cooling access. Despite immense research attention, the adoption of such technologies is limited largely due to a lack of scalability and cost compatibility with market needs. While paint and coating-based approaches offer a more sensible solution, many demonstrations suffer from issues such as a low solar reflectance performance or a lack of material sustainability due to the use of harmful solvents. In this work, we demonstrate a passive radiative cooling paint which achieves an extremely high solar reflectance value of 98% using a completely water-based formulation. Material sustainability is promoted by incorporating size-dispersed calcium phosphate biomaterials, which offer broadband solar reflectance, as well as a self-crosslinking water-based binder, providing water resistance and durability without introducing harmful materials. Common industry pigments are integrated within the binder for comparison, illustrating the benefit of finely-tuned particle size distributions for broadband solar reflectance, even in low-refractive-index materials such as calcium phosphates. With scalability, outdoor durability, and eco-friendly materials, this demonstrated paint offers a practical passive radiative cooling approach without exacerbating other environmental issues. [ABSTRACT FROM AUTHOR]

Calcium phosphate (CaP)-based materials are largely explored in orthopedics, to increase osseointegration of the prostheses and specifically in spine surgery, to permit better fusion. To address these aims, nanostructured biogenic apatite coatings are emerging, since they better mimic the characteristics of the host tissue, thus potentially being better candidates compared to their synthetic counterpart. Here, we compare hydroxyapatite (HA) nanostructured coatings, obtained by ionized jet deposition, starting from synthetic and natural sources. The starting materials and the corresponding films are characterized and compared from a compositional and morphological point of view, then their stability is studied after post-treatment annealing. Although all the films are formed by globular aggregates and show morphological features at different scales (from nano to micro), significant differences are found in composition between the synthetic and naturally derived HA in terms of magnesium and sodium content, carbonate substitution and Ca/P ratio, while differences between the coatings obtained by the different natural HA sources are minor. In addition, the shape of the aggregates is also target-dependent. All coatings have a good stability after over 14 days of immersion in medium, with natural apatite coatings showing a better behavior, as no cracking and detachments are observed during immersion. Based on these results, both synthetic and naturally derived apatitic materials appear promising for applications in spine surgery, with coatings from natural sources possessing physiochemical properties more similar to the mineral phase of the human bone tissue. [ABSTRACT FROM AUTHOR]

Bone grafting is crucial for bone regeneration. Recent studies have proposed the use of calcium citrate (CC) as a potential graft material. Notably, citrate does not inhibit hydroxyapatite (HAp) formation at specific calcium-to-citrate molar ratios. Octacalcium phosphate (OCP)/gelatine (Gel) composites, which are commonly produced from porcine Gel, are valued for their biodegradability and bone replacement capability. This study introduces fish Gel as an alternative to porcine Gel because of its wide acceptance and eco-friendliness. This is the first study to examine the interaction effects between two osteogenic materials, OCP/CC, and the influence of different gelatine matrix components on HAp formation in an SBF. Samples with varying CC contents were immersed in an SBF for 7 d and analysed using various techniques, confirming that high CC doses prevent HAp formation, whereas lower doses facilitate it. Notably, small-sized OCP/CC/porcine Gel composites exhibit a high HAp generation rate. Porcine Gel composites form denser HAp clusters, whereas fish Gel composites form larger spherical HAps. This suggests that lower CC doses not only avoid inhibiting HAp formation but also enhance it with the OCP/Gel composite. Compared with porcine Gel, fish Gel composites show less nucleation but an increased crystal growth for HAp. [ABSTRACT FROM AUTHOR]

It's imperative to create a more ideal biological scaffold for bone defect repair. Calcium phosphate bone cements (CPC) could be used as a scaffold. Some ingredients and osteogenic factors could be added to improve its poor mechanical properties and biological activity. As a macromolecule extracted from traditional Chinese medicine, Hedysarum polysaccharides (HPS) would significantly promote the osteogenic activity of bone biomaterials. Zirconium oxide and starch were added to the solid phase and citric acid was added to the liquid phase to optimize CPC. HPS was loaded onto the scaffold as an osteogenic factor, and the prepared CPS + HPS was characterized. Further, the cytocompatibility of CPS + HPS was assessed according to activity, differentiation, and calcification in neonatal rat calvarial osteoblasts, and the biosafety of CPS + HPS was evaluated according to acute toxicity, pyrogen, sensitization, and hemolysis. The success of CPS + HPS in repairing bone defects was evaluated by using a rabbit femur implantation experiment. After optimization, CPS-20-CA-5 containing 10% starch and 5% citric acid displayed the highest mechanical strength of 28.96 ± 0.03 MPa. HPS-50 was demonstrated to exert the best osteogenic effect. The combination of CPS + HPS achieved HPS-loaded CPC. Material characterization, cytocompatibility, biosafety, and femoral implantation experiments indicated that CPS + HPS possessed better pressure resistance and improved osteogenic ability in bone defect repair.CPS + HPS demonstrated effective pressure resistance and superior osteogenic ability, which may be of great significance for bone defects and bone tissue engineering to promote bone regeneration and repair. [ABSTRACT FROM AUTHOR]

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Introduction: Several calcimimetics, other than cinacalcet, are commercially available; however, their effects on calcium and phosphate levels have not yet been fully studied. We conducted a systematic review and meta‐analysis of randomized controlled trials to evaluate the impact of calcimimetics on the management of serum calcium and phosphate levels in patients with secondary hyperparathyroidism undergoing dialysis. Methods: A systematic literature search through October 2023 and a meta‐analysis were conducted on the effects of upacicalcet, etelcalcetide, evocalcet, and cinacalcet on serum calcium and phosphate levels in patients with secondary hyperparathyroidism undergoing dialysis; we searched PubMed, Ovid MEDLINE, and the Cochrane Central Register of Controlled Trials, and 21 studies comprising 6371 patients undergoing dialysis were included. Results: Participants treated with calcimimetics had lower serum calcium and phosphate levels than placebo. Conclusion: Calcimimetics significantly reduced serum calcium and phosphate levels compared to placebo in patients with secondary hyperparathyroidism undergoing dialysis, independent of therapeutic strategy or concomitant vitamin D treatment. [ABSTRACT FROM AUTHOR]

Titanium (Ti) is widely used in medical and dental implants. Calcium phosphate (CPs) coatings enhance Ti implants' osteoinductive properties, and additives further improve these coatings. Recently, a nano amorphous calcium phosphate (nACP) coating decorated with chitosan oligolactate (ChOL) and selenium (Se) showed immunomodulatory effects. This study investigates the surface morphology, composition, bioactivity, mechanical properties, and Se-release mechanism of the nACP@ChOL-Se hybrid coating on Ti substrates. Amorphous calcium phosphate (ACP) was synthesized, and the nACP@ChOL-Se hybrid coating was deposited on Ti substrates using in situ anaphoretic deposition. Physico-chemical characterization was used to analyze the surface of the coating (scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy). The distribution of Se within the coating was examined with energy-dispersive X-ray spectroscopy (EDS). Bioactivity was evaluated in simulated body fluid (SBF), and adhesion was tested using a scratch test method. In vitro testing determined the release mechanism of Se. SEM images illustrated the surface morphology, while AFM provided a detailed analysis of surface roughness. XRD analysis revealed structural and phase composition, and EDS confirmed Se distribution within the coating. The coating exhibited bioactivity in SBF and showed good adhesion according to the scratch test. In vitro testing uncovered the release mechanism of Se from the coating. This study successfully characterized the surface morphology, composition, bioactivity, and Se-release mechanism of the nACP@ChOL-Se hybrid coating on Ti substrates, offering insights for developing immunomodulatory coatings for medical and dental applications. [ABSTRACT FROM AUTHOR]

In order to enhance the corrosion resistance of calcium-based phosphate coating, the molybdenum-modified coating was successfully prepared by adding Na2MoO4 in a phosphate bath. The prepared composite film layers were studied by EDS, XRD and SEM. The corrosion resistance performances of the films were investigated by electrochemical measurements. The results showed the main composition of molybdenum-modified film was MoO2, MoP2, and MoP4, the diameter of cracks on the surface of the coating was significantly reduced, which provided better protection to the substrate. In addition, the potentiodynamic polarization curves of the molybdenum-modified film show that the corrosion potential was positively shifted by 0.068 V compared to the calcium-based phosphate coating and the corrosion current was reduced to 2.556 × 10 − 5 A · cm − 2 , indicating improved corrosion resistance. [ABSTRACT FROM AUTHOR]

Ca3(PO4)2 is selected to be added to the basalt to simulate basalt mixed sludge in order to produce glass and continuous fiber. XRD and Raman are used to analyze basalt glass with varied Ca3(PO4)2 additions. Basalt glass is amorphous, according to XRD measurements. However, Ca3(PO4)2 alters the Raman spectra of basalt glass noticeably. Raman results show Ca3(PO4)2 increases the degree of polymerization of the glass, but the degree of polymerization decreases with the further increase of Ca3(PO4)2 content. The dielectric characteristics are tested at a frequency of 1 MHz. When the addition amount of Ca3(PO4)2 is 1 g, it has the lowest dielectric constant of 6.567. When the addition amount is 2 g, it has the lowest dielectric loss of 0.0026. The volume resistivity of the sample without Ca3(PO4)2 is 4.227 × 1013 Ω· cm (25 °C). With the increase of Ca3(PO4)2 content, the volume resistivity decreases, reaching the lowest 1.78 × 1013 Ω·cm when the addition amount is 2 g (25 °C). With the increase of Ca3(PO4)2 content, the fiber diameter becomes larger, the crack decreases and the fracture frequency decrease. So the sludge can be considered as an addition in the continuous fiber production. [ABSTRACT FROM AUTHOR]

In this study, calcium-rich resource minerals such as brushite, tricalcium phosphate (TCP), and hydroxyapatite were tested as catalysts for the methanolysis of alkaline solutions of NaBH4 to generate hydrogen H2. The synthesis of calcium phosphate compounds was characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The hydrogen generation rate with the TCP catalyst (15,214 mL min−1 g−1) was higher than with the hydroxyapatite catalyst (12,437 mL min−1 g−1) and brushite catalyst (6210 mL min−1 g−1) for the methanolysis of 250 mg NaBH4 at 298 K using 25 mg of catalyst. The impact of TCP weight on hydrogen generation was studied. The methanolysis reaction led to a higher hydrogen volume generation over time with an increase in the weight of the TCP catalyst at a temperature of 308 K. The calculated activation energy for NaBH4 hydrolysis with the TCP catalyst was 23.944 kJ mol−1, suggesting the high catalytic activity of TCP. The values of enthalpy (ΔH) and entropy (ΔS) were calculated, and the results showed that ΔH was 21.28 kJ mol−1 and ΔS was −93.096 J·mol−1. ΔH was positive, meaning that the reaction was endothermic, and the negative ΔS meant a decrease in the disorder of the methanolysis reaction. The stability of the catalysis was tested in successive methanolysis tests. The catalyst's efficiency decreased to 89% after four cycles. [ABSTRACT FROM AUTHOR]

Using a titration setup to accurately control the reaction conditions and in situ monitor the reaction, we showed that fluoride exhibited negligible effects on the ion association process of calcium and phosphate and the formation of ACP nanospheres in a buffer solution with constant ionic strength. However, the stability of ACP increased with increasing fluoride concentration, which was ascribed to the inhibitory effect of fluoride on the aggregation of ACP nanospheres and the nucleation of nanocrystals on the surface of ACP nanospheres. Furthermore, fluoride could inhibit the lateral growth of HAP nanosheets and promote the formation of rod-like crystals. These results further improve our understanding of the crystallization pathway of HAP crystals and the regulatory effects of fluoride. [ABSTRACT FROM AUTHOR]

(1) Background: The aim of this study was to compare the cytotoxicity of selected resin-modified materials used in direct contact with the dental pulp (TheraCal LC, TheraCal PT, and ApaCal ART) with calcium silicate cement (Biodentine). (2) Methods: The mouse fibroblast Balb/3T3 cell line and the extracts of tested materials in four concentrations were used for the testing. An MTT assay was performed in three independent experiments with six replicates for each concentration of tested material. The cell viability (%) and cytotoxicity were expressed (cytotoxic effect is considered in cases where the cell viability is lower than 70%). The mean of the cell viability and the standard deviation were expressed for each material at all concentrations. ANOVA and Dunnet's post hoc tests were used for the statistical analysis. All of these tests were performed at the 0.05 significance level. (3) Results: At all concentrations, the cell viability was statistically significantly lower (p ≤ 0.002) for all tested materials compared to Biodentine. ApaCal ART showed a high level of cytotoxicity at all concentrations (cell viability lower than 47.71%, p < 0.0001). The same result was found for TheraCal LC at concentrations of 100%, 50% and 25% and TheraCal PT at concentrations of 100% and 50%. TheraCal LC at a 10% concentration (cell viability 68.18%) and TheraCal PT at a 25% concentration (cell viability 60.63%) indicated potential cytotoxicity. TheraCal PT at a 10% concentration was not found to be cytotoxic (cell viability 79.18%, p = 0.095). (4) Conclusion: The resin-modified calcium silicate and calcium phosphate materials showed higher cytotoxic potential, so they should be used with caution when in direct contact with the dental pulp. [ABSTRACT FROM AUTHOR]

Objectives: This study was aimed to obtain an experimental bleaching agent by adding casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) in order to eliminate the mineral loss on the tooth surface after bleaching and to evaluate the bleaching effectiveness. Materials and Methods: In this study, experimental bleaching agents containing 1%, 3% CPP‐ACP and without CPP‐ACP were obtained. Bleaching effectiveness (color change), the effect of bleaching agents on mineral content (energy dispersive x‐ray spectroscopy), surface morphology (scanning electron microscope), and surface hardness of enamel (Vicker's microhardness) before and after bleaching were evaluated. The obtained data were statistically analyzed. Results: When the bleaching levels of the groups were compared, no statistically significant difference was observed between the control and 1% CPP‐ACP groups (p > 0.05) while the addition of 3% CPP‐ACP decreased significantly the effectiveness of the bleaching agent (p < 0.05). When the effects of experimental bleaching agents on surface hardness were examined, while the enamel surface hardness decreased statistically significantly after application in the control group (p < 0.05), no statistically significant change was observed in surface hardness after the application of 1% CPP‐ACP containing bleaching agent (p > 0.05). However, a statistically significant increase was observed in surface hardness after the application of 3% CPP‐ACP containing bleaching agent (p < 0.05). When the Ca and P ratio of the groups were compared, no statistically significant difference was observed between the control and 1% CPP‐ACP groups (p > 0.05), while they increased significantly in 3% CPP‐ACP group (p < 0.05). Conclusions: The addition of 1% CPP‐ACP to the bleaching agent had positive effects on the mineral content and surface hardness of the enamel, and did not negatively affect the whitening effectiveness. Clinical Significance: Adding CPP‐ACP to the bleaching agent at appropriate concentrations can eliminate possible negative effects without compromising the effectiveness of the bleaching agent. [ABSTRACT FROM AUTHOR]

The present work evaluates chitosan/sodium alginate blended with two nanomaterials of hydroxyapatite (HA) and commercial nanoclay-Cloisite20A for improving bone regeneration. The free nano-HA, nanoclay, and their scaffolds were characterized via TEM, SEM, EDX, FTIR, XRD, and TGA analyses. In vitro bioactivity, degradation, swelling, and cytotoxicity were investigated. For the in vivo studies, two groups of rats were used (n = five) in the study period (37 days). The scaffolds were implanted in the rat's back. TEM analysis showed the nanorods of HA have a particle length of around 107 nm and a width around 17 nm, which is crystalline in nature, as XRD demonstrated. However, the SEM images showed the formation of honeycomb-like scaffolds. The in vitro bioactivity results through the changes of PBS ions and SEM/EDX analysis after immersion in PBS detected the formation of a calcium phosphate layer which is important for bone regeneration. The cell viability results proved IC50 > 670 µg/mL and IC50: 116 µg/mL for HA and nanoclay, respectively. Furthermore, the histological analysis revealed the highest calcification after 1 month for the nano-HA-containing scaffold supporting them as promising substitute biomaterials for treating bone loss. [ABSTRACT FROM AUTHOR]

Simple Summary: The normal calcification process is essential for bone formation, but calcification found elsewhere can result in cardiovascular and joint complications. Ectopic calcification, influenced by factors such as hormonal imbalance and oxidative stress, can impact soft tissues and becomes more prevalent with age and chronic illness. The stiffening of soft tissues due to calcification is a complex process influenced by cell type, interactions, the extracellular matrix, and mechanical forces. Understanding these mechanisms is vital for developing treatments for calcification-related complications. This review explores the similarities between vascular and cartilage calcifications, offering insights into both normal and pathological aspects. Physiological calcification occurs in bones and epiphyseal cartilage as they grow, whereas ectopic calcification occurs in blood vessels, cartilage, and soft tissues. Although it was formerly thought to be a passive and degenerative process associated with aging, ectopic calcification has been identified as an active cell-mediated process resembling osteogenesis, and an increasing number of studies have provided evidence for this paradigm shift. A significant association between vascular calcification and cardiovascular risk has been demonstrated by various studies, which have shown that arterial calcification has predictive value for future coronary events. With respect to cartilaginous calcification, calcium phosphate or hydroxyapatite crystals can form asymptomatic deposits in joints or periarticular tissues, contributing to the pathophysiology of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, tendinitis, and bursitis. The risk factors and sequence of events that initiate ectopic calcification, as well as the mechanisms that prevent the development of this pathology, are still topics of debate. Consequently, in this review, we focus on the nexus of the mechanisms underlying vascular and cartilaginous calcifications, trying to circumscribe the similarities and disparities between them to provide more clarity in this regard. [ABSTRACT FROM AUTHOR]

Zinc biodegradable implants represent a revolutionary advancement in medical technology, offering a promising alternative to titanium and stainless-steel implants and avoiding the need for secondary surgeries for removal. In this study, we aimed to fulfil the clinical demand for biodegradable implant materials by applying a coating of double-doped strontium and copper resorbable tricalcium phosphate (SrCu-TCP) onto a zinc-lithium (Zn-Li) biodegradable alloy using the Pulsed Laser Deposition method. The coated surfaces were thoroughly characterized using X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Atomic Force Microscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray. Microbiology experiments were conducted to assess the inhibitory effects on the growth of various bacteria strains, including gram-positive Staphylococcus aureus and Enterococcus faecalis, gram-negative Pseudomonas aeruginosa and Escherichia coli, as well as the fungus Candida albicans. The obtained results showed that the roughness of the Zn-Li alloy increased from 91.8 ± 29.4 to 651.0 ± 179.5 nm when coated with SrCu-TCP. The thickness of the coating ranged between 3–3.5 µm. The inhibition of growth for all four bacteria strains and the fungus was in the range of 24–35% when cultured on SrCu-TCP coated Zn-Li samples. These findings suggest that the developed coatings are promising candidates for applications requiring inhibition of microorganisms. [ABSTRACT FROM AUTHOR]

Bioresponsive ceramics, a new concept in ceramic biomaterials, respond to biological molecules or environments, as exemplified by salts composed of calcium ions and phosphate esters (SCPEs). SCPEs have been shown to form apatite in simulated body fluid (SBF) containing alkaline phosphatase (ALP). Thus, surface modification with SCPEs is expected to improve the apatite-forming ability of a material. In this study, we modified the surface of α-tricalcium phosphate (α-TCP) using methyl, butyl, or dodecyl phosphate to form SCPEs and investigated their apatite formation in SBF and SBF containing ALP. Although apatite did not form on the surface of the unmodified α-TCP in SBF, apatite formation was observed following surface modification with methyl or butyl phosphate. When ALP was present in SBF, apatite formation was especially remarkable on α-TCP modified with butyl phosphate. These SCPEs accelerated apatite formation by releasing calcium ions through dissolution and supplying inorganic phosphate ions, with the latter process only occurring in SBF containing ALP. Notably, no apatite formation occurred on α-TCP modified with dodecyl phosphate, likely because of the low solubility of the resulting calcium dodecyl phosphate/calcium phosphate composites. This new method of using SCPEs is anticipated to contribute to the development of novel ceramic biomaterials. [ABSTRACT FROM AUTHOR]

Simulated body fluid (SBF) and artificial saliva (AS) are used in biomedical and dental research to mimic the physiological conditions of the human body. In this study, the biomimetic precipitation of double-doped amorphous calcium phosphate in SBF and AS are compared by thermodynamic modelling of chemical equilibrium in the SBF/AS-CaCl2-MgCl2-ZnCl2-K2HPO4-H2O and SBF/AS-CaCl2-MgCl2-ZnCl2-K2HPO4-Glycine/Valine-H2O systems. The saturation indices (SIs) of possible precipitate solid phases at pH 6.5, close to pH of AS, pH 7.5, close to pH of SBF, and pH 8.5, chosen by us based on our previous experimental data, were calculated. The results show possible precipitation of the same salts with almost equal SIs in the two biomimetic environments at the studied pHs. A decrease in the saturation indices of magnesium and zinc phosphates in the presence of glycine is a prerequisite for reducing their concentrations in the precipitates. Experimental studies confirmed the thermodynamic predictions. Only X-ray amorphous calcium phosphate with incorporated Mg (5.86–8.85 mol%) and Zn (0.71–2.84 mol%) was obtained in the experimental studies, irrespective of biomimetic media and synthesis route. Solid-state nuclear magnetic resonance (NMR) analysis showed that the synthesis route affects the degree of structural disorder of the precipitates. The lowest concentration of dopant ions was obtained in the presence of glycine. Further, the behaviour of the selected amorphous phase in artificial saliva was studied. The dynamic of Ca2+, Mg2+, and Zn2+ ions between the solid and liquid phases was monitored. Both direct excitation 31P NMR spectra and 1H-31P CP-MAS spectra proved the increase in the nanocrystalline hydroxyapatite phase upon increasing the incubation time in AS, which is more pronounced in samples with lower additives. The effect of the initial concentration of doped ions on the solid phase transformation was assessed by solid-state NMR. [ABSTRACT FROM AUTHOR]

With the rapid development of tumor immunotherapy, nanoparticle vaccines have attracted much attention as potential therapeutic strategies. A systematic review and analysis must be carried out to investigate the effect of mannose modification on the immune response to nanoparticles in regulating the tumor microenvironment, as well as to explore its potential clinical application in tumor therapy. Despite the potential advantages of nanoparticle vaccines in immunotherapy, achieving an effective immune response in the tumor microenvironment remains a challenge. Tumor immune escape and the overexpression of immunosuppressive factors limit its clinical application. Therefore, our review explored how to intervene in the immunosuppressive mechanism in the tumor microenvironment through the use of mannan-decorated lipid calcium phosphate nanoparticle vaccines to improve the efficacy of immunotherapy in patients with tumors and to provide new ideas and strategies for the field of tumor therapy. [ABSTRACT FROM AUTHOR]

Cuttlefish bones are byproducts of cuttlefish processing and are readily available in the marine food industry. In this study, calcium phosphate bioceramics were prepared from cuttlefish bones using a two-stage hydrothermal calcination process. The results indicated that all bioceramics derived from cuttlefish bones had a higher degradation capacity, better bone-like apatite formation ability, and higher degree of osteogenic differentiation than commercially available hydroxyapatite. Notably, β-tricalcium phosphate, which had the highest degree of Ca2+ and Sr2+ dissolution among the bioceramics extracted, can significantly upregulate osteogenic markers (alkaline phosphatase, osteocalcin) and stimulate bone matrix mineralization. Thus, it is a promising bioceramic material for applications in bone regeneration. [ABSTRACT FROM AUTHOR]

Objective: The objective was to evaluate the remineralization effects of fluoride varnish (Clinpro White varnish), self-assembling peptide (Curodont™ Repair) and their combined use on WSL after orthodontic treatment. Materials and methods: Thirty-two subjects, aged of 10–18 (mean age 13.91 ± 2.92) with 107 post-orthodontic WSL were included in the study. Subjects were divided into four groups as control, tricalcium phosphate (TCP) containing fluoride varnish (Clinpro White varnish) group, self-assembling P11-4 peptides (Curodont™ Repair) group and combined application of the two products. At the beginning, each subjects’ caries risk profile was assessed by evaluating diet cariogenicity, plaque index, gingival bleeding index and stimulated salivary flow rate. Before the application of the remineralization agents, WSL baseline demineralization values were determined with QLF Inspektor™ Pro, laser fluorescence using DIAGNOdent and color values were measured by Vita EasyShade. Remineralization data were obtained by measuring ΔF, ΔQ, and lesion area with QLF. The aesthetic improvement after the remineralization process was evaluated with a spectrophotometer at six weeks, three and six months. Results: No statistically significant differences were found between the groups in terms of criteria determining patients’ caries risk profiles, DIAGNOdent data, and plaque index scores (p > 0.05). Intra-group evaluation following remineralization revealed statistically significant increases in ΔF and ΔQ with a decrease in lesion area for the fluoride varnish group at six months, for the peptide group at three months, and for the combined application group at three and six months (p < 0.05). In inter-group comparisons, ΔF and ΔQ values were found to be statistically significant only in the fluoride group at six months compared to the other groups (p < 0.05). While the L* value decreased significantly in all groups at six months, a statistically significant difference in ΔE* values was observed only in the control group between three and six months. Conclusion: Fluoride varnish with TCP showed highest remineralization at 6 months, and the remineralization was positively affected in the short term (three months) after the use of self-assembling P11-4 peptides and their combined application. Clinical relevance: Remineralization obtained after single application of agents tested in six months in-vivo showed parallel results. In an attempt to trigger subsurface remineralization, the combined use of fluoride with self-assembling peptides as biomimetic remineralization agent needs further evaluation. [ABSTRACT FROM AUTHOR]

Transformation of methyl lactate to acrylic acid was investigated over Ca3(PO4)2, Ca2(P2O7) and their mixture in the temperature range of 250-425 °C. The initial concentration of methyl lactate in water was varied from 2 wt% to neat methyl lactate. The results showed that these phosphate catalysts did not contain any measurable amounts of either acid sites or basic sites. The best catalyst was Ca3(PO4)2 giving 62% selectivity to acrylic acid at 75% conversion at 400 °C using GHSV of 95280 h−1 and 2 wt% methyl lactate in the initial feed. This catalyst exhibited larger surface area in comparison to Ca2(P2O7). Elemental analysis revealed that some Ca leaching occurred during reaction, while in case of Ca2(P2O7) the calcium leaching was 3.4 fold higher than observed for Ca3(PO4)2. Long-term results over Ca3(PO4)2 showed that extensive catalyst deactivation occurred during the first 11 h time-on-stream, after which the activity dropped only slightly. In addition to kinetic studies with different parameters, also, kinetic modeling was performed and the activation energies for formation of different products were determined over different catalysts. [ABSTRACT FROM AUTHOR]

In contrast to abiotically formed carbonates, biogenetic carbonates have been observed to be nanocomposite, organo-mineral structures, the basic build-blocks of which are particles of quasi-uniform size (10–100 nm) organized into complex higher-order hierarchical structures, typically with highly controlled crystal-axis alignments. Some of these characteristics serve as criteria for inferring a biological origin and the state of preservation of fossil carbonate materials, and to determine whether the biomineralization process was biologically induced or controlled. Here we show that a calcium storage structure formed by the American lobster, a gastrolith initially consisting of amorphous calcium carbonate (ACC) and amorphous calcium phosphate (ACP), post-mortem can crystallize into (thus secondary) calcite with structural properties strongly influenced by the inherited organic matrix. This secondary calcite meets many structural criteria for biominerals (thus called the biomorphic calcite), but differs in trace element distributions (e.g., P and Mg). Such observations refine the capability to determine whether a fossil carbonates can be attributed to biogenic processes, with implications for the record of life on Earth and other terrestrial planets. [ABSTRACT FROM AUTHOR]

Vitamin D3 is clinically used for the treatment of vitamin D3 deficiency or osteoporosis, partially because of its role in regulating phosphate (Pi) and calcium (Ca2+) homeostasis. The renal sodium-phosphate cotransporter 2a (Npt2a) plays an important role in Pi homeostasis; however, the role of vitamin D3 in hypophosphatemia has never been investigated. We administered vehicle or vitamin D3 to wild-type (WT) mice or hypophosphatemic Npt2a−/− mice. In contrast to WT mice, vitamin D3 treatment increased plasma Pi levels in Npt2a−/− mice, despite similar levels of reduced parathyroid hormone and increased fibroblast growth factor 23. Plasma Ca2+ was increased ~ twofold in both genotypes. Whereas WT mice were able to increase urinary Pi and Ca2+/creatinine ratios, in Npt2a−/− mice, Pi/creatinine was unchanged and Ca2+/creatinine drastically decreased, coinciding with the highest kidney Ca2+ content, highest plasma creatinine, and greatest amount of nephrocalcinosis. In Npt2a−/− mice, vitamin D3 treatment completely diminished Npt2c abundance, so that mice resembled Npt2a/c double knockout mice. Abundance of intestinal Npt2b and claudin-3 (tight junctions protein) were reduced in Npt2a−/− only, the latter might facilitate the increase in plasma Pi in Npt2a−/− mice. Npt2a might function as regulator between renal Ca2+ excretion and reabsorption in response to vitamin D3. [ABSTRACT FROM AUTHOR]