Environmentally sustainable processes for the synthesis of hydroxyapatite

Abstract

Hard tissue regeneration and regrowth have continued to be a challenge in the field of conventional medicine in this 21 st century. Over the years, the regrowth of broken bones and diseased hard tissue has remained a major concern in medical research. Since the discovery of hydroxyapatite (HA), a bioceramic compound that possesses the ability to activate bone regrowth and bond directly with regenerated bone, it has subsequently become an indispensable biomaterial. Currently, it is being used across the medical fields due to its exceptional biocompatibility. This became plausible because the main mineral phase of mammalian bones is HA. It has found application in various medical fields like medical instruments, drug delivery, bone and tooth fillers, prosthetics, orthotics, and in-vitro implants. As the importance of HA geometrically increases, it is necessary to critically evaluate and propose the most economic process of synthesizing and manufacturing this important bioceramic material. This review, therefore, highlights the different sources of HA and the synthesis/production methods for each source with a strong emphasis on the environment. Thus, the appraisal was carried out based on the properties of the derived HA. Such properties include but are not limited to geometry, particle size, morphology, thermal stability, and stoichiometry to suggest the most economic and environmentally sustainable sources and processing routes.

Ablation of Bone Tissue by Femtosecond Laser: A Path to High-Resolution Bone Surgery

“…This wavelength lies, in fact, in the vicinity of a strong absorption peak of water and hydroxyapatite, leading to high ablation efficiencies of both hard and soft tissues [ 13 ]. Hydroxyapatite is indeed a naturally occurring mineral form of calcium apatite, and in different modified forms, it represents up to 70% of the weight of human bone [ 14 ]. While bone tissue ablation rates comparable to those of mechanical approaches can be achieved with these types of laser sources, ablation remains often accompanied by important carbonization, calcination and tissue damage due to the QCW/CW characteristic of these laser sources [ 15 ].…”

Dental Applications of Systems Based on Hydroxyapatite Nanoparticles—An Evidence-Based Update

“…Synthetic hydroxyapatite can be produced using different methods, including dry methods, wet chemical reactions, or mechanochemical reactions (Figure 1), and a few of these methods can generate nanosized hydroxyapatite [29][30][31][32]. During the synthesis of hydroxyapatite nanoparticles, the challenges refer to the formation of phase impurities (other than calcium phosphate salts), as well as the difficulties in controlling the size of the particles, the size distribution, morphology, crystallinity, and degree of particle agglomeration [29,33].…”

“…Among the synthetic procedures used for the production of hydroxyapatite nanoparticles, hydrolysis, sol-gel technique, mechanochemical or wet-chemical precipitation have previously been studied [33]. Hydroxyapatite nanoparticles (HAnps) obtained through hydrolysis (a low temperature procedure) have grain sizes between 20 and 50nm, with a diverse morphology, but a high phase purity of HAnps [33,34].With a crystalline size between 20 and 60nm, the 'sol-gel' method may also be used to obtain high phase purity of HAnps, with diverse morphology [33,35]. Mechanochemical procedures can be used to synthesize nanosized hydroxyapatite with an average particle size of 25 nm, but the result is non-stoichiometric HAnps with low phase purity, even though the process can be performed at room temperature and at a low cost [33,36].…”

Prediction of the reflection intensity of natural hydroxyapatite using generalized linear model and ensemble learning methods

“…Their research findings suggest that the degradation in temperature conditions of the composite film does not necessarily influence the presence of HAp crystal. An extensive study described different sources of HAp, their respective properties (such as geometry, morphology, particle size, stoichiometry, and thermal stability), and environmental impact on the mode of material synthesis and production 11 . In recent times, the dynamic and mechanical assessment of materials have also been studied; for example, Nedaipour et al 12 examined the composition of HAp, polyethylene, glycol and a melt blend of polylactic acid in interference screws; their study analyzed the mechanical and tensile properties of the derived composite relative to material containing pure polylactic acid; the result findings suggest that the derived composite material presents better mechanical properties.…”