Search Results (29)

Metal-organic frameworks (MOFs) offer high porosity for water remediation but face challenges in handling as powders. We address these limitations by physically immobilizing Fe–BTC MOF within calcium-crosslinked low-methoxyl pectin matrices (PE–Ca–MOF). Solvent-cast films and freeze-dried foams were fabricated using water-based and polyvinylpyrrolidone (PVP)-assisted Fe–BTC dispersions, preserving MOF and pectin structures confirmed by FT–IR. PVP improved Fe–BTC dispersion and reduced particle size, enhancing distribution and plasticizing the matrix proved by DSC. Incorporation of water-dispersed Fe–BTC increased the equilibrium adsorption capacity but reduced the initial adsorption rate, while the PVP-assisted foam further enhanced uptake in comparative batch tests through its more open porous structure. At pH 7, PE–Ca–5%MOF films showed high adsorption capacities and removal efficiencies for paraquat (35.5 mg/g, 70.6%) and tetracycline (14.5 mg/g, 46.8%), while maintaining Zn²⁺ uptake compared to calcium-pectin films without MOF. Adsorption followed pseudo-first-order kinetics and Langmuir isotherms. Green regeneration with acetic acid enabled >80% capacity retention over five adsorption–desorption cycles. Foam architectures increased porosity and active-site accessibility (SEM), improving performance even at lower MOF loadings. Overall, controlling MOF dispersion and composite morphology enables efficient, reusable, and environmentally friendly bio-based adsorbents for water purification. Full article

Metallic implants used in orthopedics, such as titanium alloys, possess excellent mechanical strength but suffer from corrosion and poor bio-integration, often necessitating revision surgeries. Bioactive coatings, particularly hydroxyapatite, can enhance implant osteoconductivity, but high-purity synthetic hydroxyapatite is costly. This study investigates the development and characterization of a low-cost, biocompatible coating using hydroxyapatite derived from an unconventional natural source dromedary bone applied onto a titanium substrate via plasma spraying. Hydroxyapatite powder was synthesized from dromedary femurs through a thermal treatment process at 1000 °C. The resulting powder was then deposited onto a sandblasted titanium dioxide substrate using an atmospheric plasma spray technique. The physicochemical, structural, and morphological properties of both the source powder and the final coating were comprehensively analyzed using Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, X-ray Diffraction, and Fourier-Transform Infrared Spectroscopy. Characterization of the powder confirmed the successful synthesis of pure, crystalline hydroxyapatite, with Fourier-Transform Infrared Spectroscopy analysis verifying the complete removal of organic matter. The plasma-sprayed coating exhibited good adhesion and a homogenous, lamellar microstructure typical of thermal spray processes, with an average thickness of approximately 95 μm. X-ray Diffraction analysis of the coating revealed that while hydroxyapatite remained the primary phase, partial decomposition occurred during spraying, leading to the formation of secondary phases, including tricalcium phosphate and calcium oxide. Scanning Electron Microscopy imaging showed a porous surface composed of fully and partially melted particles, a feature potentially beneficial for bone integration. The findings demonstrate that dromedary bone is a viable and low-cost precursor for producing bioactive hydroxyapatite coatings for orthopedic implants. The plasma spray method successfully creates a well-adhered, porous coating, though process-induced phase changes must be considered for biomedical applications. Full article

Some additives currently used to enhance drilling mud’s rheological qualities have a substantial economic impact on society. Carboxymethyl cellulose (CMC) and calcium carbonate (CaCO₃) are currently imported. Food crops have influences on food security; hence, this research explored the potential of utilizing cow bone powder (CBP), a bio-waste product and a renewable resource, as an environmentally friendly fluid-loss additive for drilling applications, in comparison with CaCO₃. Both samples (CBP and CaCO₃) were evaluated to determine the most efficient powder sizes (coarse, medium, and fine powder), concentrations (5–15 g), and aging conditions (before or after aging) that would offer improved rheological and fluid-loss control. The results obtained showed that CBP had a significant impact on mud rheology when compared to CaCO₃. Decreasing the particle size (coarse to fine particles) and increasing the concentration from 5 to 15 g positively impacted mud rheology. Among all the conditions analyzed, fine-particle CBP with a 15 g concentration produced the best characteristics, including in the apparent viscosity (37 cP), plastic viscosity (29 cP), and yield point (25.5 lb/100 ft²), and a gel strength of 16 lb/100 ft² (10 s) and 28 lb/100 ft² (10 min). The filtration control ability of CaCO₃ was observed to be better than that of the coarse and medium CBP particle sizes; however, fine-particle-size CBP demonstrated a 6.1% and 34.6% fluid-loss reduction at 10 g and 15 g concentrations when compared to respective amounts of CaCO₃. The thermal behavior of the Mud Samples demonstrated that it positively impacted rheology before aging. In contrast, after aging, it exhibited a negative effect where samples grew more viscous and exceeded the API standard range for mud properties. Therefore, CBP’s excellent rheological and fluid-loss control ability makes it a potential, sustainable, and economically viable alternative to conventional materials. This superior performance enhances the thinning properties of drilling muds in stationary and circulating conditions. Full article

Calcium silicate-based sealers (CSBS) vary in chemical composition, which can influence treatment outcomes. Therefore, the study aimed at comparing several commercially available CSBS regarding microstructure and elemental characterization. Four CSBS (AH Plus Bioceramic Sealer, BioRoot RCS, BioRoot Flow, TotalFill BC Sealer) and a control resin-based sealer (AH Plus) were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction analysis (XRD). The specimens were analyzed after setting (SEM, EDX, XRD), as well as after 7 (SEM) and 28 days (SEM, EDX) of incubation in Hank’s balanced salt solution. AH Plus exhibited a uniform matrix and small amounts of calcium (Ca), significantly decreasing after incubation. In contrast, CSBSs exhibited crystalline forms on the surface and increased Ca content, significantly increasing after 28 days of incubation. The main crystalline phase for all tested CSBS was zirconium oxide, while for ERBS it was calcium tungstate. In conclusion, the amount of calcium increased on the surface of CSBSs after incubation, which alkalinized the pH, promoting mineralization, apatite formation, and antibacterial potential. Despite this, the formation of a hydroxyapatite layer was not demonstrated, possibly due to the high dissolution potential of CSBSs. Full article

Saltwater crocodile (SC; Crocodylus porosus) bone, an underutilized by-product, can be converted into high-value bio-calcium (Biocal), serving as a potential source of calcium and minerals. This study aimed to produce SC bone Biocal as functional gel enhancer for fish bologna development and to increase calcium intake. The resulting bone powder was evaluated for physicochemical, microbiological, and molecular properties. Additionally, the textural, physicochemical, structural, and sensorial properties of the formulated fish bologna incorporating Biocal at varying levels (0–10% w/w) were also evaluated. Biocal, obtained as a fine white powder, had a 16.83% yield. Mineral analysis showed 26.25% calcium and 13.72% phosphorus, with no harmful metals or pathogens detected. X-ray diffraction confirmed hydroxyapatite with 69.92% crystallinity, while calcium bioavailability was measured at 22.30%. Amino acid analysis indicated high levels of glycine, proline, and hydroxyproline, essential for collagen support. The findings confirmed that SC bone Biocal is beneficial and safe for food fortification. Incorporating SC Biocal (2–10% w/w) significantly affected the fish bologna characteristics (p < 0.05). As the Biocal level increased, the gel strength, hardness, and shear force also increased. The addition of 6% (w/w) Biocal significantly improved the textural property, without a detrimental effect on the sensory attributes of the bologna gel (p < 0.05). SDS-PAGE analysis showed TGase-enhanced myosin heavy chain (MHC) cross-linking, particularly in combination with Biocal. Moreover, the enriched Biocal–bologna gel exhibited a finer and denser microstructure. Thus, SC Biocal, particularly at 6% (w/w), can serve as a functional gel enhancer in surimi-based products, without compromising organoleptic quality. Full article

Utilizing natural fibers for production of a fully bio-based textile is an appropriate approach to align with sustainability objectives. In case of dyed products, the used dye and further finishing agents also have to be bio-based. Algae-based materials are naturally colored and can be used as a natural dye product. The present study aims to investigate the use of algae materials as a color pigment for coating on cotton as a natural fiber material using a bio-based binder. Three different algae representing blue-green algae (BGA), unicellular microalgae (UNI), and filamentous algae (FIL) are investigated as colored additives for textile coatings. The algae are applied as powder to the coating recipe together with sodium alginate as binder component. Modification of the application is conducted by addition of calcium dichloride (CaCl₂) acting as a crosslinker for the natural binder system. Using these applications, strong coloration of cotton fabrics can be achieved. Scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), color measurements, light fastness tests, and tests on the rubbing fastness are performed. Good values in rubbing and light fastness are reached (4–5 and 5, respectively) depending on the used algae material and the addition of calcium dichloride. Applications using the algae BGA and UNI perform better due to light fastness. In contrast, applications with the filamentous algae FIL lead to better rubbing fastness. The present study confirms that the proposed technique and formulations are appropriate for achieving fully bio-based, naturally colored textile products, offering a promising foundation for further research into and development of the use of algae for the modification and functionalization of textile materials. Full article

The ability of the cement to release calcium ions, which participate in the remineralization of dentin by forming apatite which improves root canal sealing with time, is of particular importance. Five recently introduced calcium-silicate commercial dental cements were investigated with a view to the influence of the physicochemical characteristics on the possibility of releasing calcium ions in an aqueous medium. Two hybrid calcium-silicate cements in the form of a paste-like ready mix (BioCal^® Cap and TheraCal LC) and three calcium-silicate cements consisting of two components—powder and liquid (Harvard MTA Universal, Rootdent, and BioFactor) were subjected to powder XRD, SEM, and EDS for detailed examination. The cements were immersed in water for 28 days and the phase composition and morphology of the cements before and after soaking were studied. The total calcium release for each cement was determined by ICP-OES. BioFactor and BioCal^® Cap release the highest amount of calcium ions, while the lowest release is registered with Rootdent and TheraCal LC. The PDT treatment of BioFactor does not influence substantially the calcium release. The impact of the elemental and phase composition on the calcium release and calcium carbonate formation was discussed. A reciprocal relation between the aluminum content and the quantity of the released calcium has been found. Full article

The evolution of biomaterials engineering allowed for the development of products that improve outcomes in the medical–dental field. Bioglasses have demonstrated the ability to either compose or replace different materials in dentistry. This study evaluated the cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp, compared to calcium hydroxide (Ca(OH)₂) paste. The 45S5 bioglass and Ca(OH)₂ powder were mixed with distilled water (ratio 2:1); Bio-C Temp is ready-for-use. Dental pulp cells were exposed to the materials’ extracts (1:2 and 1:4 dilutions; 24, 48, and 72 h) for MTT and live/dead analyses. Polyethylene tubes filled with the pastes, or left empty (control), were implanted on the dorsum of 16 rats. After 7 and 30 days (n = 8/period), the rats were euthanized and the specimens were processed for hematoxylin–eosin (H&E), von Kossa (vK), and picrosirius red (PSR) staining, or without staining for polarized light (PL) birefringence analysis. A statistical analysis was applied (p < 0.05). There was no difference in cell viability among Ca(OH)₂, 45S5 bioglass, and the control, across all periods and dilutions (p > 0.05), while Bio-C Temp was cytotoxic in all periods and dilutions compared to the control (p < 0.05). Regarding biocompatibility, there was a reduction in inflammation from 7 to 30 days for all groups, without significant differences among the groups for any period (p > 0.05). The fibrous capsules were thick for all groups at 7 days and thin at 30 days. All materials showed positive structures for vK and PL analysis. At 7 days, the control and 45S5 bioglass showed more immature collagen than the other groups (p < 0.05); at 30 days, 45S5 bioglass had more immature than mature collagen, different from the other groups (p < 0.05). In conclusion, Bio-C Temp presented cytotoxicity compared to the other materials, but the three pastes showed biocompatibility and induced calcium deposition. Additionally, the bioglass paste allowed for marked and continuous collagen proliferation. This study contributed to the development of new biomaterials and highlighted different methodologies for understanding the characteristics of medical–dental materials. Full article

The reuse of waste materials has recently become appealing due to pollution and cost reduction factors. Using waste materials can reduce environmental pollution and product costs, thus promoting sustainability. Approximately 95% of calcium carbonate-containing waste eggshells end up in landfills, unused. These eggshells, a form of bio-waste, can be repurposed as catalytic electrode material for various applications, including supercapacitors, after being converted into CaO. Similarly, used waste battery electrode materials pose environmental hazards if not properly recycled. Various types of batteries, particularly lithium-ion batteries, are extensively used worldwide. The recycling of used lithium-ion batteries has become less important considering its low economic benefits. This necessitates finding alternative methods to recover and reuse the graphite rods of spent batteries. Therefore, this study reports the conversion of waste eggshell into calcium oxide by high-temperature calcination and extraction of nanographite from spent batteries for application in energy storage fields. Both CaO and CaO/graphite were characterized for their structural, morphological, and chemical compositions using XRD, SEM, TEM, and XPS techniques. The prepared CaO/graphite nanocomposite material was evaluated for its efficiency in electrochemical supercapacitor applications. CaO and its composite with graphite powder obtained from used lithium-ion batteries demonstrated improved performance compared to CaO alone for energy storage applications. Using these waste materials for electrochemical energy storage and conversion devices results in cheaper, greener, and sustainable processes. This approach not only aids in energy storage but also promotes sustainability through waste management by reducing landfills. Full article

Pre-cooked bone is a waste product generated during tuna processing and can serve as a potential source of biocalcium (BC). Generally, non-collagenous protein and fat must be removed properly from bone. A NaCl solution can be used to remove such proteins, while fish lipase can be used in a green process, instead of solvent, for fat removal. Thus, this study aimed to investigate the impact of NaCl pretreatment at different concentrations in combination with heat to eliminate non-collagenous proteins, and to implement fish lipase treatments at varying levels for fat removal, for BC production from pre-cooked tuna bone. Optimal NaCl pretreatment of bone was achieved when a 5% NaCl solution at 80 °C was used for 150 min. The lowest lipid content was obtained for bone defatted with crude lipase extract (CLE) at 0.30 Unit/g of bone powder for 2 h. BC powder from bone defatted with CLE (DF-BC) possessed greater contents of ash, calcium, and phosphorus and smaller particle sizes than the control BC powder. X-ray diffractograms suggested that both BC powders consisted of hydroxyapatite as a major compound, which had a crystallinity of 62.92–63.07%. An elemental profile confirmed the presence of organic and inorganic matter. Thus, BC powder could be produced from pre-cooked tuna bone using this ‘green process’. Full article

This paper studies the composition and properties of shells of bivalve mollusks (Crenomytilus grayanus, Callista brevisiphonata, and Mizuhopecten yessoensis) from coastal discharges with a view to the possibility of their use in photocatalytic water treatment systems. The clam shells are considered in terms of application in the form of a powder material as a precursor for creating photocatalysts, and also as a carrier of photocatalytic coatings. It was shown that the main phase composing the shell material was calcium carbonate in two crystallographic modifications—calcite and aragonite. The presence of inorganic impurities in all studied clam shells did not exceed one mass percent. The main share was made up of elements included in the composition of calcium carbonate, which confirmed the high bio-indifference of the materials under study. Depending on the physiological and environmental features of the structure of clam shells, different contents of the organic component in their composition were observed. The granulometric characteristics of crushed clam shells (average diameter, specific surface area, and distribution modality) were studied. It was shown that the maximum values of bending strength of 5 MPa and compressive strength of 2 MPa are characterized by Mizuhopecten yessoensis shells with the lowest porosity of 2.91%. The features of sorption and photosorption processes of both whole and crushed shells in relation to four organic dyes at different temperatures and degrees of illumination were studied. Based on crushed shells of Mizuhopecten Yessoensis and titanium dioxide, functional materials (Ca_xTi_yO_z) were obtained, and their morphology and photocatalytic properties were studied. An example of the practical use of clam shells as a carrier of a photocatalytic coating is given. Full article

Calcium phosphate cements present increased biocompatibility due to their chemical composition being similar to that of the hydroxyapatite in the hard tissues of the living body. It has certain limitations due to its poor mechanical properties, such as low tensile strength and increased brittleness. Thus, the optimal way to improve properties is through the design of novel composite cements. The purpose was fulfilled using a 25% hydroxyethyl methacrylate (HEMA) mixed with 3% urethane dimethacrzlate (UDMA) base matrix with various ratios of polyethylene glycol (PEG 400) and polycaprolactone (PCL). Mineral filler is based on tricalcium phosphate (TCP) with different chitosan ratio used as bio-response enhancer additive. Four mixtures were prepared: S0—unfilled polymer matrix; S1 with 50% TCP filler; S2 with 50% chitosan + TCP filler; and S3 with 17.5% chitosan + TCP mixed with 17.5% nano hydroxyapatite (HA). The mechanical properties testing revealed that the best compressive strength was obtained by S2, followed by S3, and the worst value was obtained for the unfilled matrix. The same tendency was observed for tensile and flexural strength. These results show that the novel filler system increases the mechanical resistance of the TCP composite cements. Liquid exposure investigation reveals a relative constant solubility of the used filler systems during 21 days of exposure: the most soluble fillers being S3 and S2 revealing that the additivated TCP is more soluble than without additives ones. Thus, the filler embedding mode into the polymer matrix plays a key role in the liquid absorption. It was observed that additive filler enhances the hydrophobicity of UDMA monomer, with the matrix resulting in the lowest liquid absorption values, while the non-additivated samples are more absorbent due to the prevalence of hydrolytic aliphatic groups within PEG 400. The higher liquid absorption was obtained on the first day of immersion, and it progressively decreased with exposure time due to the relative swelling of the surface microstructural features. The obtained results are confirmed by the microstructural changes monitored by SEM microscopy. S3 and S2 present a very uniform and compact filler distribution, while S1 presents local clustering of the TCP powder at the contact with the polymer matrix. The liquid exposure revealed significant pore formation in S0 and S1 samples, while S3 and S2 proved to be more resistant against superficial erosion, proving the best resistance against liquid penetration. Full article

The aim of this laboratory study was to investigate and compare the impact of five desensitizing techniques as a treatment fortooth sensitivity on the exposed dentin after an in-office tooth bleaching procedure. Thirty intact human molars were collected for this investigation. The specimens were obtained by transversely cutting 2.5 mm of the crowns, leading to exposure of the dentin. The specimens were cleaned in an ultrasonic bath and treated initially with EDTA gel 15% for 4 min and then with Opalescence Boost bleaching gel (40% H₂O₂) for two sets of 20 min. Then, the samples were randomly divided into six groups (n = 5) and received one of the following treatments: Group 1 (no treatment—control group), Group 2 (Emofluor gel—0.4% SnF₂), Group 3 (MI Paste—CPP-ACPF), Group 4 (BioMinF paste—calcium phospho-fluoro-silicate), Group 5 (air-abrasion with ProSylc—Bioglass 45S5), and Group 6 (Er,Cr:YSGG laser). Subsequently, each sample was observed utilizing scanning electron microscopy (SEM) in order to detect the rate of occlusion of dentin tubules. SEM-EDS analysis revealed no occlusion of the dentin tubules in the control group, while Groups 2, 4, and 5 presented high effectiveness (>95% percentage of occluded tubules), and Groups 3 and 6 presented lower values (21.6 and 26.8%, respectively). It was concluded that althoughall the tested groups presented higher percentages of occlusion of the dentinal tubules compared to the control group, there were differences in effectiveness among them. The most effective treatments were the daily use of BioMinF paste and SnF₂-containing gel, as well as air-abrasion with ProSylc powder. Full article

Asian sea bass scales discarded from the fish processing industry contain collagen and calcium. The production of biocalcium can increase their value. The effect of alkaline pretreatment on non-collagenous protein removal from scales was investigated. The alkaline pretreatment of scales was optimal when 2 M NaOH solution was used for 10 min. The impacts of heating processes of varying times on chemical compositions and characteristics of biocalcium (BC) powder from alkali-pretreated scales were also studied. A lower loss of hydroxyproline (HYP) and decreased hardness of scales were obtained when the scales were treated with a boiling process. BC powders from the scales subjected to boiling (B-BC) had higher yield and HYP content than BC powders using a high-pressure heating (HP-BC) process. An augmented heating time (10–30 min) lowered yield, HYP, moisture, and protein contents in BC powder regardless of the heating processes. HP-BC powder had higher ash, calcium, and phosphorus contents than B-BC powder. A whiter color and larger mean particle size were attained for the B-BC powders. X-ray diffractograms revealed that all BC powders had hydroxyapatite, which had a crystallinity of 53.60–66.54%, as a major component. FTIR spectra confirmed that all BC powders comprised proteins and inorganic matter. BC powder from scales with high yield and satisfactory characteristics could be used in calcium supplements. Full article

The pore geometry of bone scaffolds has a major impact on their cellular response; for this reason, 3D printing is an attractive technology for bone tissue engineering, as it allows for the full control and design of the porosity. Calcium phosphate materials synthesized from natural sources have recently attracted a certain interest because of their similarity to natural bone, and they were found to show better bioactivity than synthetic compounds. Nevertheless, these materials are very challenging to be processed by 3D printing due to technological issues related to their nanometric size. In this work, bone scaffolds with different pore geometries, with a uniform size or with a size gradient, were fabricated by binder jetting 3D printing using a biphasic calcium phosphate (BCP) nanopowder derived from cuttlebones. To do so, the nanopowder was mixed with a glass-ceramic powder with a larger particle size (45–100 µm) in 1:10 weight proportions. Pure AP40mod scaffolds were also printed. The sintered scaffolds were shown to be composed mainly by hydroxyapatite (HA) and wollastonite, with the amount of HA being larger when the nanopowder was added because BCP transforms into HA during sintering at 1150 °C. The addition of bio-derived powder increases the porosity from 60% to 70%, with this indicating that the nanoparticles slow down the glass-ceramic densification. Human mesenchymal stem cells were seeded on the scaffolds to test the bioactivity in vitro. The cells’ number and metabolic activity were analyzed after 3, 5 and 10 days of culturing. The cellular behavior was found to be very similar for samples with different pore geometries and compositions. However, while the cell number was constantly increasing, the metabolic activity on the scaffolds with gradient pores and cuttlebone-derived powder decreased over time, which might be a sign of cell differentiation. Generally, all scaffolds promoted fast cell adhesion and proliferation, which were found to penetrate and colonize the 3D porous structure. Full article