Papers by Keyword: Hydroxyapatite

Abstract: The healing of bone defects is still challenging as therapies like autografts and allografts have limited benefits, especially in load-bearing positions. Bovine Hydroxyapatite (BHA) is a natural biological substance that can be used as a filler to replace damaged bones and overcome the low fracture toughness and brittleness of synthetic Hydroxyapatite (HA). This study presents the precipitation method of Magnesium (Mg)-doped Bovine Hydroxyapatite (Mg-BHA). FTIR analysis ensured the existence of phosphate (PO₄ ³), hydroxyl (OH) and carbonate (CO ^-2) groups of HA. After sintering, XRD analysis showed excellent stability in the BHA structure, represented by a slight change in Mg position. Vickers hardness showed a massive increment from ~4.6 GPa to ~7 GPa as the impurity rate increased. SEM analysis showed a denser microstructure with less porosity as the amount of Mg concentration increased. This research ensured that MgBHA could be potentially applied for medical applications due to the improvement in physical and mechanical properties of HA.

Abstract: Hydroxyapatite (HAp) derived from bovine bone waste is extensively explored for biomedical applications due to its close chemical resemblance to natural bone. However, its intrinsic brittleness and thermal instability remain critical limitations. In this study, HAp–titanium (5–20 wt.%) composites were synthesized using the self-propagating high temperature synthesis (SHS) method within the range of 750–950°C. X-ray diffraction (XRD) analysis confirmed the in-situ formation of CaTiO₃ at 850°C, which significantly improved densification and microstructural consolidation. At higher temperature (950°C), partial decomposition of HAp to tricalcium phosphate (TCP) was observed, consistent with phase evolution trends reported in the literature. Scanning electron microscopy (SEM) revealed distinct grain morphology transitions across the processing window, supporting the identified phase transformations. The results demonstrate a clear correlation between phase evolution and microstructural development: CaTiO₃ formation enhances densification, while TCP contributes to favorable bioresorbability. These findings highlight the tunability of SHS-derived HAp–Ti composites and their promising potential as bone substitute materials with adjustable bioactivity.

Abstract: Biomaterials are significantly required for medical technology. Hydroxyapatite (HA) is a bioactive material and is an excellent candidate for use as a bone replacement or bone repair material. Because HA has similar properties to human bone. However, the disadvantage of HA is its low mechanical strength. Titanium (Ti) is the famous material used to strengthen the strength of HA. This is because Ti can be used in the human body without causing undesirable reactions. The development of Ti-HA composite materials provides a bioactive material with high-strength properties. The homogeneous microstructure of materials, which is essential for achieving the required properties, can be accomplished by using composite particles as the starting materials. This research aims to develop the Ti-HA composite particles by mechanical alloying method. The mixture of Ti and HA in a mass ratio of 70:30 (Ti:HA) was milled by using a high-energy mill, i.e., a vibration mill, at a speed of 750 and 1000 rpm for 30, 60, 120, 180 and 300 minutes without inert gas supply. The results show that the Ti-HA composite particles were produced by using a vibration mill. HA particles completely cover the surface of Ti. No phase change of Ti and HA was observed under all milling conditions except at 1000 rpm for 300 minutes. The tiny XRD peaks of TiO were observed. This study developed an effective and low-cost method for producing Ti-HA composite particles, which is advantageous to engineering and medical technology.

Abstract: This study investigates the piezoelectric properties of a composite comprising polar hydroxyapatite (HA) and BaTiO₃ using an analytical model. The analysis covers the piezoelectric coefficients d₃₃ ​and d₃₁, and the specific acoustic impedance. The findings reveal that HA exhibits an unconventional d₃₃​ behavior, while the composite demonstrates a decrease in d₃₁​ and an increase in d₃₃​, with minimal BaTiO₃ content achieving d₃₃​ values similar to those of human bone (< 1 pC/N). Additionally, the d₃₁ coefficient of HA showed an unconventional behavior, highlighting its potential usage in the transverse direction. The impedance also increases from 23.5 MRayls to 31.5 MRayls, which improves acoustic wave transmission for medical imaging and therapeutic devices. These results highlight the composite's promise for bone regeneration, implantable ultrasound transducers, and energy harvesting applications.

Abstract: This study explored eggshells as an eco-friendly and cost-effective material for synthesizing hydroxyapatite. The phase compositions and morphological structure of polylactic acid composite with and without co-doped hydroxyapatite addition via a melt blending approach were evaluated. Furthermore, the biodegradation profile of the polylactic acid composite in phosphate buffer solution was studied. The concentrations of PLA/HAp, PLA/7.5MgO-7.5ZnO, and PLA/12.5MgO-2.5ZnO samples, respectively, were examined in this study. The results of morphological evaluation showed a well-distributed irregular spherical phase of hydroxyapatite. Meanwhile, the co-doped hydroxyapatite phases have variations in sizes and shapes. The polylactic acid composites showed fractured, rough, and honeycomb surfaces with interconnected pores suitable for cell propagation and enhancement, and the elemental composition proved precipitation of apatite formation. Characteristics of absorption bands of the hydroxyapatite, magnesium, zinc, and polylactic acid were present, respectively. The XRD spectra confirmed the presence of crystalline and semi-crystalline structures with percent crystallinity of 48.57%, 56.64%, and 60.08%, respectively. Meanwhile, the addition of the co-doped hydroxyapatite results in shifts in the 2θ angles of the crystal phases. The biodegradation study revealed the beneficial role of reinforcing polylactic acid composite with biogenic hydroxyapatite and hybrid doped hydroxyapatite as fillers and their synergetic effect with the pH of 7.08±0.21, 6.63±0.46, & 7.28±0.44, the porosity of 52.26±7.29, 48.57±6.74, & 43.72±5.07 %, and the degradation rate (weight loss) of 51.83±7.03, 48.16±6.85, & 43.66±5.46, respectively. Findings revealed that the current study aligns with the sustainable biodegradable composite used in bone tissue repair and hence contributed towards sustainable material without polluting the environment.

Abstract: The surface wettability of metallic biomaterials significantly influences the biological response of biomedical implants. However, the optimal degree of wettability depends on the specific coating or surface treatment applied to the biomaterial. Researchers have widely utilised hydroxyapatite coatings to modify implant surfaces to enhance bioactivity, biocompatibility, and osseointegration. This review article discussed the impact of hydroxyapatite-doped coatings on the surface wettability of metallic biomaterials. A systematic search of Scopus and Web of Science databases was conducted to review recent studies investigating the wettability and biological response of hydroxyapatite-doped coatings applied through standard implant surface deposition techniques. Results reveal that hydroxyapatite-doped coatings are typically hydrophilic and have higher surface energy than uncoated hydrophobic metallic surfaces. The hydrophilic nature promotes better interaction with biological fluids, resulting in cell adhesion and proliferation. The rough and porous surface increases wettability as fluid can easily penetrate the craters. Further research may elucidate the complex connectivity of deposition method process parameters with surface wettability and biological outcomes. This review briefly overviews current research on hydroxyapatite-doped coatings and their effects on surface wettability and biointegration.

Abstract: Despite several advantages of hydroxyapatite, the main shortcoming is its low mechanical properties. The aim of the research study is the production and characterization of Rice Husk Ash reinforced hydroxyapatite ceramic composite for bone repair. The effect of Rice Husk Ash content and sintering temperature on the wear rate, physical and mechanical properties of the fabricated composite was investigated. The porosities obtained for the samples range from 39±0.1 to 56.53±0.14%. The porosity obtained in this study falls within the range of 40 and 90% which makes it suitable for osteo-integration. The trend from the mechanical properties shows that the addition of the rice husk ash significantly improves the measurement since it serves as a barrier to the propagation of cracks and consequently serves as an additional toughening mechanism. The wear rates obtained for the samples are 0.036, 0006, 0.0016, 0.009 for 0, 0.5, 1, and 1.5 wt.%RHA respectively. This shows that the wear rate of the samples reduces drastically with the addition of the rice husk.

Abstract: Poly (methyl methacrylate) or PMMA is an acrylic material has been used widely as a denture base material. The denture base materials should exhibit good mechanical properties and dimensional stability in moist environment. Hydroxyapatite (HAp) as a filler is added to improve the mechanical properties of the denture base. Process for the manufacture of denture base composites consists of a synthesis of polymethyl methacrylate (PMMA) with suspension polymerization process, treatment filler hydroxyapatite, mixing component powder and liquid, molding and curing process. hydroxyapatite concentrations used were 0%, 1.5%, 3%, 4.5%, 6%, 7.5% and 9%. Characterization of PMMA product resulted an average particle size of 48.7 microns, dominant percentage of taxicity in atactic 39.5% and syndiotactic 60.7%. In the FTIR spectra, no impurity compounds were detected in PMMA products. The highest tensile strength value was found in hydroxyapatite which contained 6%, which was 63.87 MPa according to the PMMA standard for denture base.

Abstract: This study aims to create a gel base composition that has the potential to be combined with hydroxyapatite from the biogenic material Crassostrea gigas as a gel that can repair dental caries. The base gel composition consists of Na-CMC, guar gum, and glycerin which can dissolve the HA element without settling so that it can be applied well to the teeth. nano HA contained in Crassostrea gigas can potentially remineralize and improve caries in teeth. Therefore, it is inevitable that the base gel is safe to make composites with nano HA as a function of repairing dental caries. The potential of HA as a tooth remineralization material was proven by the SEM, FTIR, and XRD characterization of CaCO₃ and CaO, which have sharp crystallinity. The base gel is safe to be applied to the bones of the teeth by the MTT test treatment. This proves that the base gel is not toxic and has high viability of 92.66% at a dose of 31.25 μg/mL. The IC50 value was 688.6 μg/ml. These results are safe to be applied with nano HA material and are safe to be applied to the bones of the teeth.

Abstract: Aligned calcium phosphate nanorods embedded in gelatin nanofibers were fabricated to be applied as a coating material on the Ti bone implant using the conventional electrospinning method. Calcium phosphate nanorods with a strong positively charged surface were prepared by modifying with alanine (alanine/HA) to facilitate the arrangement of nanoparticles under the electric field in the electrospinning process, followed by mild hydrothermal treatment to preserve the structure of fibers. Scanning electron microscope, atomic force microscope, and transmission electron microscope measurements confirmed that the composite fibers were smooth without the presence of particles on the surface and alanine/HA was aligned within the fiber. The tensile strength of the prepared scaffolds was identical to that of the cancellous bone (2 to 12 MPa). According to MTT assay, the scaffold coated Ti showed a significant improvement on cell adhesion and biocompatibility compared to uncoated Ti.