Two types of hydroxyapatite were synthesized: pure hydroxyapatite and 5% magnesium-doped hydroxyapatite (based on weight percentage): pure hydroxyapatite and 5% magnesium-doped hydroxyapatite (based on weight percentage).
Abstract
Hydroxyapatite is widely used as a bioceramic material in orthopedic and dental field because of its exceptional biocompatibility and bioactivity. Hydroxyapatite (HAp) doped with several mineral ions has been frequently reported to further enhance its bioactive nature. Several studies indicate that biological waste materials can serve as calcium sources for hydroxyapatite synthesis, with eggshells being one such promising source. In the present work, two types of hydroxyapatite were synthesized: pure hydroxyapatite and 5% magnesium-doped hydroxyapatite (based on weight percentage). Laboratory-grade calcium hydroxide was used for synthetic HAp, while eggshell powder was employed for eggshell-derived HAp. The activity of the developed materials in biological environment was assessed using in vitro methods. Porous ceramic blocks were fabricated by compacting the powders using a hydraulic press and sintering them at 950°C. Powder samples calcined at 800°C were analysed by X-ray diffraction (XRD) to assess the lattice parameters and functional groups identification was done by Fourier transform infrared spectroscopy (FTIR) to identify. Apparent porosity was determined using Archimedes’ principle, confirming the presence of pores in the pellets. Hemolysis studies demonstrated that the synthesized materials are hemocompatible. Simulated body fluid (SBF) studies confirmed the appearance of apatite layer on the sintered pellets, establishing the bioactive and interactive nature of the developed materials.
This study investigates the conversion of human and cattle (goat and cow) teeth into bioactive hydroxyapatite-based composites and presents a detailed comparative evaluation of these biogenic materials with laboratory-synthesised (synthetic) hydroxyapatite (HAp). In this work, hydroxyapatite was extracted from human and bovine teeth through controlled calcination and milling, while synthetic HAp was prepared using a standard wet chemical precipitation route. All materials were subsequently sintered at 900 °C and fabricated into pellets for physical and biological analysis. X-ray diffraction (XRD) analysis confirmed that all samples—synthetic and biogenic—possessed crystalline structures consistent with stoichiometric hexagonal hydroxyapatite. FTIR spectra revealed characteristic phosphate, hydroxyl, and carbonate functional groups, with biogenic samples showing slightly higher carbonate substitution. Physical characterization demonstrated comparable hardness, shrinkage behaviour, densification, and porosity among the samples, with only minor variations attributable to natural ionic substitutions present in biological apatite. SEM analysis revealed interconnected porous microstructures favourable for osteoconduction, while pore-size distribution remained consistent across all groups. A strong negative correlation between porosity and hardness (r = –0.996) affirmed the influence of pore architecture on mechanical properties. Biological evaluations validated the suitability of the materials for biomedical use. MTT cytotoxicity assays demonstrated high cell viability (>95%) for all samples, indicating excellent cytocompatibility. Haemolysis percentages remained below the ASTM threshold of 5%, confirming hemocompatibility. Simulated Body Fluid (SBF) immersion studies showed enhanced apatite formation in biogenic HAp compared to synthetic HAp, highlighting superior bioactivity due to natural trace ions and surface reactivity. The findings establish human and cattle teeth as promising, sustainable resources for producing high‑quality hydroxyapatite suitable for applications in bone regeneration, implant coatings, and other biomedical domains.
Subhasis Nath, S. Debnath, Soumya Mukherjee et al.· Journal of Polymer & Composi...· 0 citations
Hydroxyapatite (HA) is widely used in biomedical applications due to its biocompatibility and chemical similarity to the mineral phase of bone; however, its low mechanical strength limits its structural use. In this work, HA ceramics with different Mg additions (0, 0.5, 1, 3, 5, and 10% by weight) were prepared using the powder processing technique. The mixtures were homogenized, conformed and sintered at 1100 °C. The incorporation of intermediate Mg concentrations produced an increase in fracture toughness compared to pure HA. The best mechanical performance was obtained with the formulation containing 5% Mg by weight, achieving a hardness of 319 HV, a porosity of 12.92% and a fracture toughness of 4.06 MPa·m0.5, comparable to those reported for human cortical bone, indicating its potential for applications in moderately loaded bone implants. The findings indicate that magnesium functions as a reinforcing component in the ceramic matrix, mitigating critical defects and thereby contributing to the improved toughness of Mg-containing hydroxyapatite ceramics. The polarization resistance results show that the incorporation of low fractions by weight of magnesium (1% Mg) adjusts the electrochemical behavior of the material, while higher increases in its concentration cause a deterioration of this property.
Elizabeth Refugio-García, Z. I. Bedolla-Valdez, Alfredo Emiliano Chávez-Pantiga et al.· Applied Biosciences· 0 citations
The use of biogenic hydroxyapatite as a sustainable and bioactive alternative to synthetic ceramics has attracted increasing attention for 3D-printed scaffolds in bone tissue engineering. In this work, calcium alginate-based scaffolds reinforced with commercial (cHA) and biogenic hydroxyapatite (bHA) obtained from croaker fish bones (Micropogonias furnieri) were fabricated by 3D printing using hydroxyapatite contents ranging from 10% to 20%. Both hydroxyapatites exhibited hexagonal structures, and all formulations showed rheological behavior suitable for extrusion-based printing. Structural analyses revealed increased diffraction peak intensity with higher hydroxyapatite content, while FTIR spectra showed no significant structural changes. Hydroxyapatite addition increased the compressive modulus, although higher loadings reduced maximum resistance and produced denser, less porous structures. After 14 days in simulated body fluid, scaffolds containing 10% bHA favored apatite deposition, evidenced by increased phosphorus levels. In vitro assays using MC3T3-E1 pre-osteoblasts demonstrated biocompatibility, with metabolic viability above 70% and no toxicity. The 10% bHA formulation also enhanced cell proliferation, adhesion, and migration without increasing reactive oxygen or nitrogen species. Alizarin Red staining indicated osteogenic potential, while micronucleus assays with CHO-K1 cells confirmed the absence of genotoxicity. These findings highlight the potential of biogenic hydroxyapatite scaffolds for bone tissue engineering.
Diana Gabriela Nina-Nina, Giovanna de Amorim Grasser, Amanda Sardeli Alqualo et al.· Marine Drugs· 0 citations
