Incorporated Calcium Phosphate Research Articles

Surface modification of iron-zinc ions incorporated calcium phosphate biocomposite flexible films for biomedical applications

In this work, the poly(methyl methacrylate) (PMMA)-Iron (Fe)-Zinc (Zn) ions incorporated hydroxyapatite nanocomposite films were developed by solvent evaporation technique and exposed to nitrogen 7+ ions implantation on different fluences viz., 1 × 1015, 5 × 1015, and 1 × 1016 ions/cm2 are denoted as PFZH115, PFZH515, and PFZH116 respectively. The N7+ ion implantation modified the surface properties but did not affect the bulk properties of the films. The ion beam implantation leads to the polymer chain scission and free radical formation due to the production of localized heating. The bombardment of the low-energy ions removed the oxygen in the composite matrix resulting in the replacement of nitrogen ions. The ion-induced surface diffusion results in the orientation of polarized dipoles and the reduction of wettability. All the samples are hemocompatible. The formation of craters is due to the continuous impingement of the ion beams that paved the way for the leaching of zinc ions from the hydroxyapatite matrix leading to the increased antimicrobial activity of the films. The surface engineering led to the proliferation of fibroblast cells by 10% which made the ion beam implantation a potential way to fabricate novel bone/dental filling materials in the biomedical field.

Facilitated osteogenesis of magnesium implant by coating of strontium incorporated calcium phosphate.

This study investigated the corrosion resistance and biocompatibility of magnesium coated with strontium-doped calcium phosphate (Sr-CaP) for dental and orthopedic applications. Sr-CaP was coated on biodegradable magnesium using a chemical dipping method. Magnesium coated with Sr-CaP exhibited better corrosion resistance than pure magnesium. Sr-CaP-coated magnesium showed excellent cell proliferation and differentiation. Additionally, new bone formation was confirmed in vivo. Therefore, Sr-CaP-coated magnesium with reduced degradation and improved biocompatibility can be used for orthopedic and dental implant applications.

Enhanced in vitro inhibition of MCF-7 and magnetic properties of cobalt incorporated calcium phosphate (HAp and β-TCP) nanoparticles

The Co2+ (0.1 M) incorporated hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) nanoparticles were synthesized by the microwave assisted technique and sintering of HAp respectively. The samples were thermally treated at temperatures ranging from 200 to 1000°C. The partial substitutions of Co2+ at the Ca2+ site of HAp were confirmed from the slight shift (∼0.2°) in the (002) and (211) XRD peaks. The morphology of the nanoparticles was transformed from nanospheres to twinned particles on thermal treatment. In addition, the particle size of Co-600 was increased (from ∼50 nm to ∼100 nm) due to the recrystallization process. Further, the thermal treatment enhanced the crystallinity (41.15 to 90.16%), retentivity (Mr) and coercivity (Hc) of the nanoparticles. The cobalt incorporated HAp and β-TCP possessed paramagnetic property. The excellent bioactivity of β-TCP has been confirmed by the mineralization in simulated body fluid (SBF). Compared to HAp, β-TCP possessed better compatibility towards C2C12 cells on cobalt incorporation as evidenced by the in vitro cell viability. Moreover, both HAp and β-TCP have significantly inhibited the growth of MCF-7 on increasing the interaction time (72 h). Hence, the inhibition characteristics of Co2+ incorporated calcium phosphate (CaP) towards MCF-7 (without affecting the normal cells) demonstrate its competency as a potential material for cancer therapy over the already existing nanoparticles.

Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study.

ObjectivesThe evaluation of three different drug delivery modes of bone morphogenetic protein‐2 (BMP‐2) in healing peri‐implant bone defects in beagle dogs. BMP‐2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP‐2 on the surface of CaP granules: as a coating incorporated depot.Material and MethodsAfter extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri‐implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP‐2; SC plus the subsequent filling of the defect with CaP adsorbed BMP‐2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP‐2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP‐2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants.ResultsIn Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP‐2 biomimetically prepared CaP (BioCaP), whereby the BMP‐2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants.ConclusionThis study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP‐2 internally incorporated BMP‐2, whereby BMP‐2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants.

Synthesis of Antibacterial Hybrid Hydroxyapatite/Collagen/Polysaccharide Bioactive Membranes and Their Effect on Osteoblast Culture.

Inspired by the composition and confined environment provided by collagen fibrils during bone formation, this study aimed to compare two different strategies to synthesize bioactive hybrid membranes and to assess the role the organic matrix plays as physical confinement during mineral phase deposition. The hybrid membranes were prepared by (1) incorporating calcium phosphate in a biopolymeric membrane for in situ hydroxyapatite (HAp) precipitation in the interstices of the biopolymeric membrane as a confined environment (Methodology 1) or (2) adding synthetic HAp nanoparticles (SHAp) to the freshly prepared biopolymeric membrane (Methodology 2). The biopolymeric membranes were based on hydrolyzed collagen (HC) and chitosan (Cht) or κ-carrageenan (κ-carr). The hybrid membranes presented homogeneous and continuous dispersion of the mineral particles embedded in the biopolymeric membrane interstices and enhanced mechanical properties. The importance of the confined spaces in biomineralization was confirmed by controlled biomimetic HAp precipitation via Methodology 1. HAp precipitation after immersion in simulated body fluid attested that the hybrid membranes were bioactive. Hybrid membranes containing Cht were not toxic to the osteoblasts. Hybrid membranes added with silver nanoparticles (AgNPs) displayed antibacterial action against different clinically important pathogenic microorganisms. Overall, these results open simple and promising pathways to develop a new generation of bioactive hybrid membranes with controllable degradation rates and antimicrobial properties.

Modification of physicochemical properties and bioactivity of oxide coatings formed on Ti substrates via plasma electrolytic oxidation in crystalline and amorphous calcium phosphate particle suspensions

One way to improve characteristics of oxide coatings prepared by plasma electrolytic oxidation (PEO) method in suspensions lies in variation of solid particle properties. In this study, the effect of particle crystallinity on different physicochemical properties and bioactivity of coatings prepared on Ti and Ti6Al4V substrates was studied, and repeatability of resulting characteristics was assessed depending on selected substrates. PEO was performed in direct current mode at a voltage of 350 V in electrolytes containing 0.1 M KH2PO4 and 100 g.L-1 of stoichiometric crystalline hydroxyapatite or amorphous tricalcium phosphate particles with average size of ∼ 450 nm. Series of measured physical parameters included coating thickness, as well as surface wettability, roughness and topography. Surface and cross-sectional chemical composition was studied by Raman and EDX spectroscopy, while bioactivity was evaluated with simulated body fluid tests. Results showed specific influence of particle crystallinity on surface morphology and repeatable particle incorporation pattern depending on the substrate utilized. It was found that amorphous particles lead to the increased amount of incorporated calcium phosphate phases followed by improved coating bioactivity and possible explanation of this phenomenon was suggested. Variation of particle crystallinity was proposed as a new potential instrument for the adjustment of PEO coating properties.

Remineralizing Ability of Resin Composite Incorporating Calcium Phosphate Nanoparticles and Fluoride Containing Adhesive.

Remineralizing Ability of Resin Composite Incorporating Calcium Phosphate Nanoparticles and Fluoride Containing Adhesive.

Micro-Nano Surface Characterization and Bioactivity of a Calcium Phosphate-Incorporated Titanium Implant Surface.

The surface topography of dental implants and micro-nano surface characterization have gained particular interest for the improvement of the osseointegration phases. The aim of this study was to evaluate the surface micro-nanomorphology and bioactivity (apatite forming ability) of Ossean® surface, a resorbable blast medium (RBM) blasted surface further processed through the incorporation of a low amount of calcium phosphate. The implants were analyzed using environmental scanning electronic microscopy (ESEM), connected to Energy dispersive X-ray spectroscopy (EDX), field emission gun SEM-EDX (SEM-FEG) micro-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) before and after immersion in weekly refreshed Hank’s balanced salt solution (HBSS) for 28 days. The analysis of the samples before immersion showed a moderately rough surface, with micropits and microgrooves distributed on all of the surface; EDX microanalysis revealed the constitutional elements of the implant surface, namely titanium (Ti), aluminum (Al) and vanadium (V). Limited traces of calcium (Ca) and phosphorous (P) were detected, attributable to the incorporated calcium phosphate. No traces of calcium phosphate phases were detected by micro-Raman spectroscopy. ESEM analysis of the implant aged in HBSS for 28 days revealed a significantly different surface, compared to the implant before immersion. At original magnifications <2000×, a homogeneous mineral layer was present on all the surface, covering all the pits and microgrooves. At original magnifications ≥10,000×, the mineral layer revealed the presence of small microspherulites. The structure of these spherulites (approx. 2 µm diameter) was observed in nanoimmersion mode revealing a regular shape with a hairy-like contour. Micro-Raman analysis showed the presence of B-type carbonated apatite on the implant surface, which was further confirmed by XPS analysis. This implant showed a micro-nano-textured surface supporting the formation of a biocompatible apatite when immersed in HBSS. These properties may likely favor bone anchorage and healing by stimulation of mineralizing cells.

Strontium-calcium phosphate hybrid cement with enhanced osteogenic and angiogenic properties for vascularised bone regeneration.

Vascularized bone tissue engineering is regarded as one of the optimal treatment options for large bone defects. The lack of angiogenic properties and unsatisfactory physicochemical performance restricts calcium phosphate cement (CPC) from application in vascularized bone tissue engineering. Our previous studies have developed a starch and BaSO4 incorporated calcium phosphate hybrid cement (CPHC) with improved mechanical strength and handling properties. However, the bioactivity-especially the angiogenic ability-is still absent and requires further improvement. Herein, based on the reported CPHC and the osteogenic and angiogenic properties of strontium (Sr) ions, a strontium-enhanced calcium phosphate hybrid cement (Sr-CPHC) was developed to improve both biological and physicochemical properties of CPC. Compared to CPC, the initial setting time of Sr-CPHC was prolonged from 2.2 min to 20.7 min. The compressive strength of Sr-CPHC improved from 11.21 MPa to 45.52 MPa compared with CPC as well. Sr-CPHC was biocompatible and showed promotion of alkaline phosphatase (ALP) activity, calcium nodule formation and osteogenic relative gene expression, suggesting high osteogenic-inductivity. Sr-CPHC also facilitated the migration and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro and up-regulated the expression of the vascular endothelial growth factor (VEGF) and Angiopoietin-1 (Ang-1). In vivo evaluation showed marked new bone formation in a rat calvarial defect model with Sr-CPHC implanted. Sr-CPHC also exhibited enhancement of neovascularization in subcutaneous connective tissue in a rat subcutaneous implantation model. Thus, the Sr-CPHC with the dual effects of osteogenesis and angiogenesis shows great potential for clinical applications such as the repair of ischemic osteonecrosis and critical-size bone defects.

In vitro evaluation of degradable electrospun polylactic acid/bioactive calcium phosphate ormoglass scaffolds

Nowadays, the main limitation for clinical application of scaffolds is considered to be an insufficient vascularization of the implanted platforms and healing tissues. In our studies, we proposed a novel PLA-based hybrid platform with aligned and random fibrous internal structure and incorporated calcium phosphate (CaP) ormoglass nanoparticles (0, 10, 20 and 30 wt%) as an off-the-shelf method for obtaining scaffolds with pro-angiogenic properties. Complex morphological and physicochemical evaluation of PLA–CaP ormoglass composites was performed before and after in vitro degradation test in SBF solution to assess their biological potential. The degradation process of PLA–CaP ormoglass composites was accompanied by numerous CaP-based precipitations with extended topography and cauliflower-like shape which may enhance bonding of the material with the bone tissue and accelerate the regenerative process. Random fiber orientation was preferable for CaP compounds deposition upon in vitro degradation. CaP compounds precipitated firstly for randomly oriented composite nonwovens with 20 and 30 wt% addition of ormoglass. Moreover, the preliminary bioactivity test has shown that BSA adsorbed to PLA–CaP ormoglass composites (both aligned and randomly oriented) with 20 and 30 wt% of ormoglass nanoparticles which was not observed for pure PLA scaffolds.

Fracture characterization of novel bioceramic microbeads filled polymer composite

The biomaterial poly(l-lactic acid) (PLLA) is commonly used for bone fixation devices and dental surgeries; however its natural osseointegrating ability is generally poor, which can lead to dislocation and partial fractures. Recently, calcium phosphate bioceramics have been incorporated into PLLA in order to redress this issue and improve the osseointegrating ability of the material. This study incorporated calcium phosphate microbeads in PLLA at various concentrations and measured their effect on the critical stress intensity factor, KIC and critical energy release rate at crack initiation, Gin, as well as the unusual fracture mechanic they induced. The inclusion of microbeads into the polymer matrix reduced the materials’ fracture toughness, from a KIC of 34 ± 7 Pa m−1/2 for blank PLLA, to 18 ± 1 Pa m−1/2 for the strongest bead containing group; and from a Gin of 1030 ± 150 J m−2 for blank PLLA to 200 ± 18 J m−2 for the same microbead containing group. Importantly however, the microbead containing groups fractured by a different mechanism, which was identified by observing fracture surface morphologies, electron probe microanalysis and finite element analysis. It was seen that polymer intruded into the porous microbeads, and resulted in regions of increased stiffness in the polymer matrix around each bead. This prevented void formation at the polymer/microbead interface, but it allowed the strain energy density to increase rapidly under load in microbead containing groups. This energy concentration in turn caused fractures to occur sooner, and resulted in the brittle fracture surfaces seen around microbeads. The identification of this fracture mechanism is important to understand, as it suggests a way to greatly improve the fracture toughness of the material, reducing the difference in stiffness of the two components. This fracture mechanism may also be useful in explaining other observed fracture events containing two materials of greatly varying stiffness.

Novel multifunctional of magnesium ions (Mg++) incorporated calcium phosphate nanostructures

Magnesium ions incorporated calcium phosphate was synthesized by wet chemical route and followed by microwave assisted method. XRD analysis was confirmed that the presence of calcium phosphate (hydroxyapatite). TEM analysis was exhibited rod-like morphology. XRF results were showed the percentage of calcium, phosphate, magnesium and oxygen. There was a slight blue shift observed in magnesium ions based samples. Higher magnesium (0.1 Mg-HAp) was revealed the greater discharging time with capacitance voltage (0.55 V). Magnesium based calcium phosphate was showed prolonged rate of drug release. At higher frequency, the Nyquist plot was showed the electrochemical behavior, however at lower frequency, revealed mass transfer process. Magnesium ions tailor the specific capacitance of calcium phosphate. Therefore, magnesium ions based phosphate samples could be an outstanding multifunctional candidate for drug release and supercapacitor applications.

Improving the biocompatibility of tobermorite by incorporating calcium phosphate clusters.

In our earlier work, tobermorite containing calcium phosphate (CP) clusters (CP-Tob) was hydrothermally prepared in the CaO-SiO2-P2O5-H2O system for biomedical applications. CP-Tob was used to investigate the influence of CP cluster incorporation on its biocompatibility. Tobermorite samples with and without CP clusters were hydrothermally prepared at 180°C for 40 h. The biocompatibility, structure, and density of states of the tobermorite samples were investigated by experimental and first principles methods. The amounts of lysozyme and bovine serum albumin adsorbed on CP-Tob were higher than those on tobermorite without CP clusters. Cluster incorporation caused a decrease in the solubility, resulting in the enhancement of the cell compatibility. The calculated results indicated that incorporating clusters, which interact with the silicate units of tobermorite, led to a change of the density of states of tobermorite. Incorporation of CP clusters in tobermorite led to improvement of the biocompatibility evaluated by biological and computational analyses.

Poly(trimethylene carbonate)-based composite materials for reconstruction of critical-sized cranial bone defects in sheep

PurposeThe use of ceramic materials in repair of bone defects is limited to non-load-bearing sites. We tested poly(trimethylene carbonate) (PTMC) combined with β-tricalcium phosphate or biphasic calcium phosphate particles for reconstruction of cranial defects. Materials and methodsPTMC-calcium phosphate composite matrices were implanted in cranial defects in sheep for 3 and 9 months. Micro-computed tomography quantification and histological observation were performed for analysis. ResultsNo differences were found in new bone formation among the defects left unfilled, filled with PTMC scaffolds, or filled with either kind of PTMC-calcium phosphate composite scaffolds. Porous β-TCP scaffolds as control led to a larger amount of newly formed bone in the defects than all other materials. Histology revealed abundant new bone formation in the defects filled with porous β-TCP scaffolds. New bone formation was limited in defects filled with PTMC scaffolds or different PTMC-calcium phosphate matrices. PTMC matrices were degraded uneventfully. New bone formation within the defects followed an orderly pattern. ConclusionsPTMC did not interfere with bone regeneration in sheep cranial defects and is suitable as a polymer matrix for incorporating calcium phosphate particles. Increasing the content of calcium phosphate particles in the composite matrices may enhance the beneficial effects of the particles on new bone formation.

Controlled and Tunable Biomimetic Apatite Mineralization of Synthetic Hydrogels

There has been much work examining bioinspired mineralization of polymeric hydrogels with calcium phosphates, yet a systematic method for the predictable and tunable synthesis of biomimetic apatites is yet to be developed. Here, a method for the selective mineralization of substituted apatite composite hydrogels where the incorporated mineral phase is formed as a result of a chemical reaction within the hydrogel matrix is presented. Mineralized hydrogels are prepared by precipitating the apatite precursor phase dicalcium phosphate dihydrate (DCPD) in a poly(vinyl alcohol) (PVA) solution, which is then crosslinked into a composite hydrogel by cyclic freeze/thawing. The encapsulated DCPD is hydrolyzed to apatite by immersion in buffers at 37 °C. Tuning the pH (7.4, 9) and ionic composition (CO3 2−, F−) of the buffer influence the morphology and chemical composition of the apatite product. The incorporated calcium phosphate polymorph is monitored by X‐ray diffraction, attenuated total reflectance‐fourier transform infrared spectroscopy (ATR‐FTIR), and scanning electron microscope‐energy dispersive X‐ray. The apatite–PVA hydrogels promote cellular adhesion and viability. The method developed here demonstrates diffusion‐mediated transformation of a calcium phosphate precursor phase within a hydrogel matrix to various substituted apatites in a selective and predictable manner.image

A physicochemical process for fabricating submicrometer hollow fluorescent spheres of Tb3+-incorporated calcium phosphate

The submicrometer hollow fluorescent spheres of Tb3+-incorporated calcium phosphate (CaP) were successfully fabricated by pulsed laser irradiation of the dispersion of carbon-integrated hydroxyapatite (HAp) nanopowders into Tb3+ ethanol solution.

Mineralized collagen scaffolds induce hMSC osteogenesis and matrix remodeling.

Biomaterials for bone tissue engineering must be able to instruct cell behavior in the presence of the complex biophysical and biomolecular environments encountered in vivo. While soluble supplementation strategies have been identified to enhance osteogenesis, they are subject to significant diffusive loss in vivo or the need for frequent re-addition in vitro. This investigation therefore explored whether biophysical and biochemical properties of a mineralized collagen-GAG scaffold were sufficient to enhance human mesenchymal stem cell (hMSC) osteogenic differentiation and matrix remodeling in the absence of supplementation. We examined hMSC metabolic health, osteogenic and matrix gene expression profiles, as well as matrix remodeling and mineral formation as a function of scaffold mineral content. We found that scaffold mineral content enhanced long term hMSC metabolic activity relative to non-mineralized scaffolds. While osteogenic supplementation or exogenous BMP-2 could enhance some markers of hMSC osteogenesis in the mineralized scaffold, we found the mineralized scaffold was itself sufficient to induce osteogenic gene expression, matrix remodeling, and mineral formation. Given significant potential for unintended consequences with the use of mixed media formulations and potential for diffusive loss in vivo, these findings will inform the design of instructive biomaterials for regenerative repair of critical-sized bone defects, as well as for applications where non-uniform responses are required, such as in biomaterials to address spatially-graded interfaces between orthopedic tissues.

Rapid determination of hydrogen peroxide produced by Lactobacillus using enzyme coupled rhodamine isocyanide/calcium phosphate nanoparticles

A sensitive method for detecting hydrogen peroxide (H2O2) using rhodamine isocyanide incorporated calcium phosphate nanoparticles (Rho/CaP) was developed. The synthesized nanoparticles were characterized based on transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction patterns (XRD). To study the application, the nanoparticles were functionalized with horse radish peroxidase (HRP) based on aminopropyl triethoxy silane (APTES) and used as tools to detect H2O2. The detection strategy was based on fluorescence quenching or colorimetric detection. The enzyme immobilized nanoparticles were titrated with different concentrations of H2O2 and a fixed concentration of O-phenylenediamine (OPD). The HRP conjugated Rho/CaP strongly catalyzed H2O2 oxidation of OPD that caused fluorescence quenching at 575nm. For colorimetric detection, the OPD product was read at 492nm. In the fluorescence quenching assay, the minimum detectable concentration was ~1pmol in contrast to ~5nmol in the colorimetric assay. The minimum detectable concentration by visual detection was ~500nmol. The specificity of the developed assay method was examined with different interferences which did not produce any significant response. This assay was applied, along with a commercially available kit to compare the H2O2 production capacities of different Lactobacillus strains. The results indicated that the developed assay and commercially available kit methods were highly correlated. The fluorescence quenching kinetics is also discussed.

In vitro evaluation of bioactive strontium-based ceramic with rabbit adipose-derived stem cells for bone tissue regeneration

The development of bone replacement materials is an important objective in the field of orthopaedic surgery. Due to the drawbacks of treating bone defects with autografts, synthetic bone graft materials have become optional. So in this work, a bone tissue engineering approach with radiopaque bioactive strontium incorporated calcium phosphate was proposed for the preliminary cytocompatibility studies for bone substitutes. Accumulating evidence indicates that strontium containing biomaterials promote enhanced bone repair and radiopacity for easy imaging. Hence, strontium calcium phosphate (SrCaPO4) and hydroxyapatite scaffolds have been investigated for its ability to support and sustain the growth of rabbit adipose-derived mesenchymal stem cells (RADMSCs) in vitro. They were characterized via Micro-CT for pore size distribution. Cells used were isolated from New Zealand White rabbit adipose tissue, characterized by FACS and via differentiation into the osteogenic lineage by alkaline phosphatase, Masson's trichome, Alizarin Red and von Kossa staining on day 28. Material-cell interaction was observed by SEM imaging of cell morphology on contact with material. Live-Dead analysis was done by confocal laser scanning microscopy and cell cluster analysis via μCT. The in vitro biodegradation, elution and nucleation of apatite formation of the material was evaluated using simulated body fluid and phosphate buffered saline in static regime up to 28 days at 37 °C. These results demonstrated that SrCaPO4 is a good candidate for bone tissue engineering applications and with osteogenically-induced RADMSCs, they may serve as potential implants for the repair of critical-sized bone defects.

Arsenic Removal by Precipitation with Calcium Phosphate Hydroxyapatite

The removal of arsenic from synthetic arsenic contaminated water sample by precipitating arsenic (in the form of arsenate oxyanion) with calcium phosphate hydroxyapatite, HAp, was studied under conditions that induce arsenate incorporated calcium phosphate hydroxyapatite, Ca (P/As)HAp, to form. Arsenate is able to substitute for a fraction of the phosphate in HAp host material as it forms. Consequently, arsenic is successfully removed from the contaminated water achieving up to 99% arsenic removal from 25 ppm initial arsenic concentration. The Ca:(P+As) and P:As mole ratios were found to play an important role in arsenic removal efficiency. Higher Ca:(P+As) and P:As mole ratios give higher arsenic removal efficiency. Surprisingly, the pH of the initial anion solution, a key parameter in arsenic speciation, was found to not have a significant effect on arsenic removal by this process. The advantage of this process is that the precipitation can occur rapidly at relatively low levels of arsenic contamination, implying an easy and inexpensive process for arsenic removal can be developed based on this approach.