Natural Calcium Research Articles

Synergistic Effect of Dipping in Aloe Vera Gel and Mixing with Chitosan or Calcium Chloride on the Activities of Antioxidant Enzymes and Cold Storage Potential of Peach (Prunus persica L.) Fruits

Peach is a climacteric fruit characterized by a rapid maturation, high respiration level, weight loss, breakdown of texture, and interior browning. Fast tempering of the fruit and subsequent mold expansion caused a negative impact on the marketing. This study was carried out to estimate the synergistic influence of coating with Aloe vera gel (AVG) at 15% or 30% mixed with chitosan (CH) at 1.5% as a kind of natural polymers or calcium chloride (CaCl2) at 3% on physical and chemical features. We investigated the changes in antioxidant enzymes activities of peach fruits Prunus persica (L.) Metghamer Sultany. Fruits were kept at 3 ± 1 °C and relative humidity (RH) 85–90% for 36 days during two consecutive seasons (2020 and 2021). Results revealed that applying AVG at 30% blended with CH at 1.5% significantly impacted the storage period of peach fruits, reduced the ion leakage (IL), malondialdehyde (MDA), and lessened weight loss. The differences were significant compared to the other treatments and untreated fruits (control) that exhibited the higher values for IL, MDA, and weight loss in the 36th day. Moreover, fruit quality features such as firmness, total acidity (TA), total soluble solids (TSS), and skin color chroma (c*), hue angle (h) were also maintained. Furthermore, this combination was raised of phenolic content, antioxidant capacity (DPPH), antioxidant enzyme activity such as catalase (CAT), peroxidase (POD), and quench the generation of H2O2 and O2•−. It could be concluded that dipping peach fruits in AVG at 30% blended with CH at 1.5% retained the biological features of peach fruit at considerable levels during cold storing. Thus, this effective mixture can be utilized to prolong the storage and marketing period of peach fruits. Nevertheless, a more in-depth analysis is required for this edible coating to be successfully commercialized in the peach fruit post-harvest industry.

Conceptual Review of Pravala (Coral) – A Marine Source of Natural Calcium

Background: Pravala (Coral) is one among the nine ratnas (precious stones), as categorized by all the texts of Rasashastra. Pravala is widely used in ayurvedic practice being a rich source of natural calcium and various trace elements. Objective: To critically review and highlight potential natural sources of calcium:pravala from classical and contemporary literature with recent research works. Data source: Ancient Indian literature, Classical texts of Rasa shastra from Rasa Hridaya Tantra (9th Cent. A.D) to Rasa Tarangini (20th Cent. A.D). Materials and Methods: Present work has reviewed and compiled a detailed description of Pravalaparyaya (synonyms), utpatti (Occurrence), bheda (types), grahya/agrahya laxanas (Considerable/Nonconsiderable properties for medicinal preparations), guna karma (Pharmacological and therapeutic properties), shodhana (Purification), Marana (Incineration), pishtikalpana (fine powder), matra (Dose) amayika prayoga (Therapeutic utility) and Yogas (Compound formulations) with its contemporary science relevance. Result: Data from the critical review of classical and contemporary research works. Conclusion: Pravala being natural source of calcium, is administered in the form of Bhasma (Calyx) and Pishti (Paste)for curing ailments such as Amlapitta (Hyperacidity), Netra Roga (Eye diseases), and Hridaya Roga (Cardiac diseases). Pravala is having pitta shamaka (Soothing effect) and Asthiposhaka (Bone mineralization) properties ideally indicated to treat mainly disorders of pitta aggravation and asthikshaya (Calcium deficiency).

Bioperformance Studies of Biphasic Calcium Phosphate Scaffolds Extracted from Fish Bones Impregnated with Free Curcumin and Complexed with β-Cyclodextrin in Bone Regeneration.

Fish bones are a natural calcium phosphate (CaP) sources used in biomaterials production for bone regeneration. CaP scaffolds can be enriched with other substances with biological activity to improve bone repair. This study aimed to evaluate the physicochemical properties and bone regeneration potential of biphasic calcium phosphate (BCP) scaffolds impregnated with free curcumin (BCP-CL) or complexed with β-cyclodextrin (BCP-CD) compared to BCP scaffolds. Rietveld’s refinement showed that BCP is composed of 57.2% of HAp and 42.8% of β-TCP and the molar ratio of Ca/P corresponds to 1.59. The scaffolds presented porosity (macro and microporosity) of 57.21%. Apatite formation occurred on the BCP, BCP-CL, and BCP-CD surface, in vitro, in SBF. Micro-Raman technique showed a reduction in the dissolution rate of β-TCP in the curcumin-impregnated scaffolds over time, and in vivo studies on critical-size defects, in rat calvaria, had no additional regenerative effect of BCP-CL and BCP-CD scaffolds, compared to BCP scaffolds. Despite this, the study showed that curcumin impregnation in BCP scaffolds prolongs the release of the β-TCP phase, the BCP- phase with the higher osteoinductive potential, representing an advantage in tissue engineering.

Utilization of Scallop Shells (Placuna placenta) for Potential Water Filter Prototype in Jaring Halus Village, Jaring Halus-Langkat District and the Characterization Test

Indonesia is a maritime country that has abundant marine wealth. Unfortunately, most fishers still live in poor conditions, including Jaring Halus Village, Secanggang District, Langkat Regency, North Sumatra Province. Previous research has shown that there is much coastal waste, such as Scallop Shells (Placuna placenta), that are not treated, even though it has the potential to help people who are experiencing water crises to get clean water sources. This study aimed to characterize the shells of Scallops and produce calcium carbonate as an activated carbon product to produce clean water. The method used to characterize the mashed scallop shells is X-Ray Diffraction (XRD). In this study, three different sizes, namely 25 μm, 90 μm, and 150 μm, will be compared, and the size and quality selected to produce the best calcium carbonate were tested at different temperatures, namely 800°C, 900°C, 1000°C, and 1100°C. In the x-ray diffraction analysis test, the smallest particle is 25 μm, which has the highest intensity compared to other sizes. The best particle size, which is heated/calcined at a temperature of 1100, has the highest intensity, which can remove all impurities and produce natural calcium carbonate, which is more stable. Based on the study results, it can be concluded that the best calcium carbonate is produced from particles with a size of 25 μm which are calcined at the highest temperature of 1100°C.

In Vitro Corrosion Resistance of a Layer-by-Layer Engineered Hybrid Coating on ZK60 Magnesium Alloy

Magnesium alloys are next generation biodegradable implants for clinical applications. However, their medical applications are currently hampered by their rapid corrosion rate in the physiological environment. To overcome such limitations, we have applied a novel layer-by-layer engineering approach of introducing anodization-induced microrough oxidized surface on ZK60 magnesium alloy, followed by surface mineralization with natural calcium apatite (hydroxyapatite, HA), and surface coating with natural protein (silk fibroin, SF); which, effectively reduces corrosion and degradation rate of ZK60 in simulated body fluid. Anodization of ZK60 improved the surface adhesion strength of HA layer; HA layer increased the surface roughness, hydrophilicity and micro-hardness, whereas decreased ionic release; SF layer decreased surface microroughness and hydrophilicity, whereas improved the stability of HA layer. The SF + HA coating on anodized ZK60 effectively decreased the in vitro weight loss (degradation) by almost six times, whereas corrosion rate by more than two orders in magnitude. Such interfacial coatings, with biocompatible SF on the outer surface, could potentially expand the application of ZK60 in the field of biomedical engineering.

The Roles of Platelet-Activating Factor and Magnesium in Pathophysiology of Hypertension, Atherogenesis, Cardiovascular Disease, Stroke and Aging

Hypertension and atherosclerosis are debilitating diseases that affect millions each year. Long-term consequences include but are not limited to stroke, myocardial infarction, and kidney failure. Platelet-activating factor (PAF) is a proinflammatory mediator synthesized from a subclass of phosphatidylcholines that increases platelet activation, leukocyte adhesion, infiltration of macrophages, and intracellular lipid accumulation, thereby contributing to atherosclerosis. Magnesium, a key micronutrient and free radical scavenger, is a water-soluble mineral that regulates peripheral vasodilation and calcium, phosphate, and hydroxyapatite homeostasis. Magnesium’s antihypertensive ability stems from its role as a natural calcium antagonist and promoter of vasodilatory mediators, such as nitric oxide. Platelet-activating factor and magnesium share an inverse relationship, and elevated magnesium levels have been shown to have protective effects against plaque formation as well as antihypertensive and antiarrhythmic effects, all of which allow for healthier aging. The purpose of this literature review is to investigate the role of platelet-activating factor and magnesium in the pathophysiology of hypertension, atherosclerosis, cardiovascular disease, stroke, and aging. Since the pathophysiology of the platelet-activating factor biomolecule is underexplored, further research studies are warranted in order to navigate the putative signaling pathways involved in the cardioprotective effects of dietary magnesium as a natural anti-PAF agent.

One-step fabrication of hydrophilic lignosulfonate-decorated reduced graphene oxide to enhance the pervaporation performance of calcium alginate membranes

In this study, a reduced graphene oxide (rGO)@sodium lignosulfonate (NaLS) composite material was fabtricated using a one-step method and then mixed with natural polysaccharide calcium alginate (CaAlg) to prepare the [email protected]/CaAlg pervaporation membrane. The appearance and physical properties of the [email protected]/CaAlg membrane were characterized by scanning electron microscopy and water contact angle. The swelling performance of the membrane and its dehydration performance to organic solvents were evaluated. The results indicate that the addition of [email protected] can increase the hydrophilicity of the [email protected]/CaAlg membrane and reduce its degree of swelling in the ethanol solution. The membrane incorporated with 6 wt% [email protected] exhibits the best pervaporation performance, and ethanol can be purified to 99.8%.

Production cross sections of 47Sc via alpha-particle-induced reactions on natural calcium up to 29 MeV

Production cross sections of a medical radioisotope 47Sc via alpha-particle-induced reactions on natural calcium were measured up to 29 MeV. The stacked-foil activation technique and gamma-ray spectrometry were adopted for the experiment. Cross sections of simultaneously formed radionuclides 46,44m,44g,43Sc and 47Ca were also determined. Physical yields of the alpha-particle-induced reactions on natCa and 44Ca were deduced from the measured cross sections.

Characteristics of sandy soil treated using EICP-based urease enzymatic acceleration method and natural hemp fibers

This study presents the use of biocementation process with EICP-based urease enzymatic acceleration method and natural hemp fibers to improve the strength of sandy soil. The amount of hemp fibers mixed in the sandy soil is varied up to 20% by volume. Different tests are used, and results are observed. From real-time bender element tests, the optimum amount of natural hemp fibers for mixing in biocemented sand is found to be 2.5% by volume, based on shear wave velocity and initial shear modulus. Moreover, the process of biocementation requires a few days before the start of reaction, and the reaction fully occurs at 4-day while finishes at 6-day. Using pH meter, it is found that the process of biocementation reaches its maximum value at 3-day, because the solution pH in sand becomes higher than 7. After that, the biocementation reaction rate decreases due to the reduction of the solution pH. From spectophotometer, the ammonification occurs from 0-day to 4-day, and reaches its maximum at 4-day. After that, it gradually decreases showing the gradual end of biocementation reaction. The SEM results show that the surface of natural hemp fibers and precipitated calcium carbonate (CaCO3) crystals are rough indicating the potential for bonding between them. The SEM results also show that the precipitated CaCO3 fills within the voids between sand particles and natural hemp fibers, resulting in the enhancement of sandy soil strength. The XRD results show the relationship between the occurrence of CaCO3 and the process of biocemented in sand. Finally, the direct shear tests confirm the improvement of sandy soil properties via increasing cohesion and internal friction angle due to biocementation and hemp fibers.

Study on the Influence of Alkali Activator Solutions on Strength Improvement of Pozzolan Calcium Hydroxide Binders

Alkali activated binder, commonly known as geopolymer cement, has replaced Portland cement in the production of mortar and concrete globally over the past few years. The density, particle size distribution, and specific surface area (SSA) are important physical parameters affecting strength and durability of alkali activated binders. This study carried out tests for physical and chemical properties of the natural pozzolan and calcium hydroxide and then determines the influence of alkali solution (sodium silicate and sodium hydroxide) on strength development of natural pozzolan calcium hydroxide binders. The particle size distribution (PSD), relative densities (RD), and specific surface areas (SSA) of powder natural pozzolan and calcium hydroxide materials and for the mixture of natural pozzolan and calcium hydroxide were determined by using Blaine air permeability apparatus. The optimum proportion of 75% natural pozzolan and 25% calcium hydroxide was obtained which produces the compressive strength of 7.5 MPa at 28 days cured paste. The mixture of natural pozzolan and calcium hydroxide were further grinded at three different finenesses and the particle size gradation, specific densities, specific surface areas and mean particles sizes for the mixture were determined. The compressive strength of alkali activated binders increased with increasing curing period and fineness. The maximum compressive strength for 28 days cured specimens was 26.1 MPa which was obtained at a solution of 8 moles sodium hydroxide concentration. The test results showed that natural pozzolan materials can be used to make geopolymer binders for mortars and concretes. The geopolymer binders for mortars and concretes reduce green gas emission from cement factory but also it can be used to produce durable mortar and concrete with comparable strengths with mortars and concrete made from conventional Portland cement.

Reduced graphene oxide-incorporated calcium phosphate cements with pulsed electromagnetic fields for bone regeneration.

Natural calcium phosphate cements (CPCs) derived from sintered animal bone have been investigated to treat bone defects, but their low mechanical strength remains a critical limitation. Graphene improves the mechanical properties of scaffolds and promotes higher osteoinduction. To this end, reduced graphene oxide-incorporated natural calcium phosphate cements (RGO-CPCs) are fabricated for reinforcement of CPCs' characteristics. Pulsed electromagnetic fields (PEMFs) were additionally applied to RGO-CPCs to promote osteogenic differentiation ability. The fabricated RGO-CPCs show distinct surface properties and chemical properties according to the RGO concentration. The RGO-CPCs’ mechanical properties are significantly increased compared to CPCs owing to chemical bonding between RGO and CPCs. In in vitro studies using a mouse osteoblast cell line and rat-derived adipose stem cells, RGO-CPCs are not severely toxic to either cell type. Cell migration study, western blotting, immunocytochemistry, and alizarin red staining assay reveal that osteoinductivity as well as osteoconductivity of RGO-CPCs was highly increased. In in vivo study, RGO-CPCs not only promoted bone ingrowth but also enhanced osteogenic differentiation of stem cells. Application of PEMFs enhanced the osteogenic differentiation of stem cells. RGO-CPCs with PEMFs can overcome the flaws of previously developed natural CPCs and are anticipated to open the gate to clinical application for bone repair and regeneration.

Insights into Sorption-Mineralization Mechanism for Sustainable Granular Composite of MgO-CaO-Al2O3-SiO2-CO2 Based on Nanosized Adsorption Centers and Its Effect on Aqueous Cu(II) Removal.

Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-Al2O3-SiO2-CO2 with nanosized adsorption centers was synthesized using natural calcium–magnesium carbonates and clay aluminosilicates for copper sorption. An organometallic modifier was added as a temporary binder and a source of inovalent ions participating in the reactions of defect formation and activated sintering. The sorbent-mineralizer samples of specified composition and properties showed irreversible sorption of Cu2+ ions by the ion exchange reactions Ca2+ ↔ Cu2+ and Mg2+ ↔ Cu2+. The topochemical reactions of the ion exchange 2OH− → CO32−, 2OH− → SO42− and CO32− → SO42− occurred at the surface with formation of the mixed calcium–copper carbonates and sulfates structurally connected with aluminosilicate matrix. The reverse migration of ions to the environment is blocked by the subsequent mineralization of the newly formed interconnected aluminosilicate and carbonate structures.

تقنيات ترميم صينية نحاسية أثرية بمتحف الفن الإسلامي بالقاهرة

A copper tray dating back to the Mamluk era, kept in the stores of the Museum of Islamic Art in Cairo, registered under No. 9315. It was broken into six separate parts with several holes. Its edge is serrated by a line in the prominent Naskh script. The tray suffers from various deterioration factors, such as pits and holes in different places of the tray, and the wrong restoration, as it was welded incorrectly with the aim of assembling some of its separate parts. Various examinations and analyses were carried out. The results of the X-ray diffraction analysis showed the presence of Cuprite (Cu2O), Atacamite and Paratacamite. Treatment and conservation of the tray was carried out, including mechanical cleaning and chemical cleaning. The assembly process was carried out for the separate parts. The holes were completed using mixture of epoxy with natural oxides and calcium carbonate with microballoon as a filler. The tray was also isolated using 3% benzotriazole to protect it from exposure to corrosion.

Improved separation scheme for 44Sc produced by irradiation of natCa targets with 12.8 MeV protons

Introduction44Sc is of great interest as a positron emission tomography (PET) radionuclide due to its suitable nuclear characteristics: Eβ+max = 1.47 MeV, branching ratio 94.3% and convenient half-life of 3.97 h. Here, 44Sc was produced via the widely used reaction 44Ca (p,n)44Sc using natural calcium as a target. MethodsThe irradiation was performed at TRIUMF using the 13 MeV cyclotron. The separation consisted of a combination of DGA branched resin and Dowex 50Wx8 (200–400 mesh). The distribution coefficients of Sc3+ on Dowex 50Wx8 (NH4+ form, 200–400 mesh) with ammonium α-hydroxyisobutyrate (pH = 4.8) medium were determined in this study. Results and conclusionThe tested scheme allows both a reliable separation of 44Sc from the target material as well as from the other competitive metals and a final fraction with high specific activity. The achieved radiochemical yield was 95 ± 3%.

Determination of natural thorium isotopes (230Th and 232Th) in calcium and magnesium supplements and the potential effective exposure radiation dose for human

The article presents a study on the content of radiotoxic thorium radionuclides, alpha-emitting 230Th and 232Th, as a possible additional source of these radioisotopes in the human diet in the most popular calcium and magnesium supplements available for adults in Poland. It was also examined whether the supplements impact the value of effective radiation doses to the consumers. The analyzed pharmaceuticals contained different organic or inorganic calcium or magnesium compounds, and some of them were of natural origin, while most of the organic compounds were synthetic. Based on the study, the 230Th concentrations in natural origin calcium and magnesium supplements were significantly higher than in synthetic. The results showed that the highest value of 230Th activity was found in natural origin pills produced from chalk and equalled 6.20 ± 0.17 m Bq/g, while the highest 232Th activity concentration was determined in the dolomite sample and determined at 0.58 ± 0.05 m Bq/g. The evaluation showed that calcium and magnesium supplements could contribute to an annual effective radiation dose of less than 3 μSv, but the amount is much than the annual radiation dose from 230Th and 232Th decay ingested with daily food (0.3 μSv). For this reason, the consumption of these supplements may increase the annual effective radiation dose received by a human. Notwithstanding, the exposure is considered low from the radiological and toxicological points of view.

Relationship of dietary magnesium intake and serum magnesium with hypertension: a review.

The relationship between magnesium and hypertension has been intensively investigated in the last few decades. Most of the so far reviews were focused on either dietary magnesium or serum magnesium or magnesium supplements. Our goal was to merge these findings with a more comprehensive approach. Internet search was performed in PubMed database without date limits, using the following search terms "dietary magnesium," "serum magnesium," "magnesium supplements," "hypertension," "drinking water," "food," "endothelial dysfunction," "arterial smooth muscle," and "arterial spasms." In general, there exists an inverse dose-dependent relationship between dietary magnesium intake and serum magnesium and the risk of hypertension. A negative correlation has been found between the serum magnesium concentration and Framingham risk score and intima-media carotid thickness and cardiovascular mortality. On the other hand, concentration of extracellular magnesium in the normal range acts as a natural calcium channel blocker, eliminates endothelial dysfunction, increases nitric oxide, and induces direct and indirect vasodilatation. In conclusion, an average magnesium dietary intake is below the recommended values and magnesium supplementation in the prevention and treatment of hypertension might be justified.

Effects of quantity and source of calcium on the behavior of goat milk after heating and acidification

This study investigated changes in the behavior of goat milk protein and physicochemical characteristics of high-pasteurized goat milk and goat milk yogurt during storage caused by calcium chloride and natural milk calcium addition and decalcification. Compared with the control group, the denaturation temperature of goat milk protein dropped in all the treated groups. The addition of both types of calcium accelerated the transition of goat milk protein from β-sheet to β-turn and random coil structure. But opposite results were found in the decalcification process. Compared with calcium chloride, natural milk calcium showed more positive influence on the stability of high-pasteurized milk during storage. The addition of both types of calcium improved significantly the water-holding capacity of yogurt during 7-day storage, and the natural milk calcium dramatically inhibited the post-acidification of yogurt. This study provides a theoretical basis for further study and the development of calcium-based functional goat milk products.

Nano-Hydroxyapatite vs. Xenografts: Synthesis, Characterization, and In Vitro Behavior.

This research focused on the synthesis of apatite, starting from a natural biogenic calcium source (egg-shells) and its chemical and morpho-structural characterization in comparison with two commercial xenografts used as a bone substitute in dentistry. The synthesis route for the hydroxyapatite powder was the microwave-assisted hydrothermal technique, starting from annealed egg-shells as the precursor for lime and di-base ammonium phosphate as the phosphate precursor. The powders were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), X-ray fluorescence spectroscopy (XRF), and cytotoxicity assay in contact with amniotic fluid stem cell (AFSC) cultures. Compositional and structural similarities or differences between the powder synthesized from egg-shells (HA1) and the two commercial xenograft powders—Bio-Oss®, totally deproteinized cortical bovine bone, and Gen-Os®, partially deproteinized porcine bone—were revealed. The HA1 specimen presented a single mineral phase as polycrystalline apatite with a high crystallinity (Xc 0.92), a crystallite size of 43.73 nm, preferential growth under the c axes (002) direction, where it mineralizes in bone, a nano-rod particle morphology, and average lengths up to 77.29 nm and diameters up to 21.74 nm. The surface of the HA1 nanoparticles and internal mesopores (mean size of 3.3 ± 1.6 nm), acquired from high-pressure hydrothermal maturation, along with the precursor’s nature, could be responsible for the improved biocompatibility, biomolecule adhesion, and osteoconductive abilities in bone substitute applications. The cytotoxicity assay showed a better AFSC cell viability for HA1 powder than the commercial xenografts did, similar oxidative stress to the control sample, and improved results compared with Gen-Os. The presented preliminary biocompatibility results are promising for bone tissue regeneration applications of HA1, and the study will continue with further tests on osteoblast differentiation and mineralization.

The Impact of Natural Calcium Carbonate and Ubiquinone on Bone Mineral Density in Rabbits

Objective: The aim of this study was to investigate the effect of ubiquinone and/or calcium carbonate (CaCO3) on bone mineral density in rabbits at healing site in mandibular bone postoperatively. Materials and Methods: Sixty healthy white male New Zealand rabbits almost the same age, weight and circumstance were used in this study. All animals were submitted to operation in the mandibular bone region. The groove of 2mm diameter and 6mm length was drilled by the heavy-duty dental engine. After operation rabbits were randomly divided into six groups (each group 10 rabbits) five rabbits for each period; control group (groove was not filled by anything) and treated groups which subdivided into five groups as follows: group I (groove was filled with Ubiquinone), group II (groove was filled with CaCO3), group III (groove was filled with CaCO3: Ubiquinone as a ratio (1:1)), group IV (groove was filled with CaCO3: Ubiquinone as a ratio (1:2)) and group V (groove was filled with CaCO3: Ubiquinone as a ratio (2:1)). Estimated BMD using Densitometry analysis was measured after 15 and 30 days respectively. Results: Statistical analysis showed significant differences between all groups (control and treated). The estimated BMD showed significant increase group I(101±1.05), group II(111±2.23), group III(125±3.54), group IV(126±5.13) and group V(133±6.29) comparing to control group (92±0.15) at follow-up times at 15 day. Also in the present study we found that significant decrease in BMD after 30 days of operation in group I(144±3.45), group II(153±6.24), group III(160±8.94), group IV(165±9.11) and group V(182±12.56) compare to control group(109±1.25) respectively. Adding the ubiquinone and/or CaCO3 showed a significant increase in BMD manifested by bone healing like space-filling and newly formed bone trabeculae and a high number of lacunas compared with the control group. Conclusion: This study concluded that the addition of ubiquinone and/or CaCO3 was successfully increasing in bone healing by increasing BMD compared with the control group. Keywords: Ubiquinone, CaCO3, Bone healing, BMD (Bone Mineral Density).

Zinc-substituted hydroxyapatite produced from calcium precursor derived from eggshells

The availability of natural calcium derived from biowaste materials is an inexpensive alternative to commercial calcium reagents used to produce calcium phosphate bioceramics. This approach is more ecofriendly, cost effective and sustainable owing to its abundant availability. In this study, zinc-substituted hydroxyapatite (ZnHA-Es) was synthesised using calcium precursor derived from eggshells through precipitation method. Zn concentration was varied from 1 mol% to 5 mol% during the synthesis, and the derived powders were calcined at 700 °C in air atmosphere. XRD analysis revealed that ZnHA-Es powders were highly crystalline and comprised biphasic mixtures of HA as the major phase and β-tricalcium phosphate as the minor phase. FTIR examination indicated that all ZnHA-Es samples had a similar structure to pure HA as evidenced by the presence of frequency bands corresponding to phosphate, carbonate and hydroxyl functional groups. The disappearance of vibrational bands of carbonate groups became more apparent with increased Zn concentration. Microstructure analysis revealed that the derived nanostructured particles were spherical (approximately 40–100 nm in diameter) regardless of Zn substitution.