Calcium Phosphate Compounds Research Articles

Fabrication and characterization of reinforced glass ionomer cement by zinc oxide and hydroxyapatite nanoparticles

This study shows the enhancement of glass ionomer cement (GIC) by incorporating hydroxyapatite (HA) and zinc oxide (ZnO) nanoparticles to improve its mechanical strength, biological activity, and antibacterial properties. GC is widely used in dental and orthopedic applications due to its bioactivity and biocompatibility, but it suffers from weak antibacterial properties and limited load-bearing capacity. HA, a calcium phosphate compound similar to natural bone, and ZnO, known for its antibacterial and bone-regenerative properties, were integrated into GIC to address these limitations. The modified GC exhibited improved compressive strength and bioactivity, particularly with the addition of 4 wt% ZnO nanoparticles, which showed the highest increase in mechanical performance while maintaining cytocompatibility. However, the fluoride release was reduced, indicating an exchange between enhanced mechanical properties and fluoride ion release. Antibacterial efficacy was assessed using well diffusion, MIC, and MBC tests, confirming that the modified GC has significant potential in dental and orthopedic applications. Future research should focus on the long-term effects of Zn2⁺ ion release to fully understand its impact on the antibacterial performance of the cement.

An Advanced Surface Treatment Technique for Coating Three-Dimensional-Printed Polyamide 12 by Hydroxyapatite

Polymer 3D printing has is used in a wide range of applications in the medical field. Polyamide 12 (PA12) is a versatile synthetic polymer that has been used to reconstruct bony defects. Coating its surface with calcium phosphate compounds, such as hydroxyapatite (HA), could enhance its bonding with bone. The aim of this study was to coat 3D-printed polyamide 12 specimens with hydroxyapatite by a simple innovative surface treatment using light-cured resin cement. Polyamide 12 powder was printed by selective laser sintering to produce 80 disc-shaped specimens (15 mm diameter × 1.5 mm thickness). The specimens were divided randomly into two main groups: (1) control group (untreated), where the surface of the specimens was left without any modifications; (2) treated group, where the surface of the specimens was coated with hydroxyapatite by a new method using a light-cured dental cement. The coated specimens were characterised by both Fourier transform infrared spectroscopy (FTIR) and Transmission Electron Microscopy (TEM), (n = 10/test). The control and treated groups were further randomly subdivided into two subgroups according to the immersion in phosphate-buffered saline (PBS). The first subgroup was not immersed in PBS and was left as 3D-printed, while the second subgroup was immersed in PBS for 15 days (n = 10/subgroup). The surfaces of the control and treated specimens were examined using an environmental scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA) before and after immersion in PBS. Following the standard American Society for Testing and Materials (ASTM D3359), a cross-cut adhesion test was performed. The results of the FTIR spectroscopy of the coated specimens were confirmed the HA bands. The TEM micrograph revealed agglomerated particles in the coat. The SEM micrographs of the control 3D-printed polyamide 12 specimens illustrated the sintered 3D-printed particles with minimal porosity. Their EDXA revealed the presence of carbon, nitrogen, and oxygen as atomic%: 52.1, 23.8, 24.1 respectively. After immersion in PBS, there were no major changes in the control specimens as detected by SEM and EDXA. The microstructure of the coated specimens showed deposited clusters of calcium and phosphorus on the surface, in addition to carbon, nitrogen, and oxygen, with atomic%: 9.5, 5.9, 7.2, 30.9, and 46.5, respectively. This coat was stable after immersion, as observed by SEM and EDXA. The coat adhesion test demonstrated a stable coat with just a few loose coating flakes (area removed <5%) on the surface of the HA-coated specimens. It could be concluded that the 3D-printed polyamide 12 could be coated with hydroxyapatite using light-cured resin cement.

Influence of Self-Assembly Peptides Usage in Combination with Fluorides and Calcium Phosphate Compounds upon Remineralization for Incipient Carious Lesions

Influence of Self-Assembly Peptides Usage in Combination with Fluorides and Calcium Phosphate Compounds upon Remineralization for Incipient Carious Lesions

Laser-induced three-dimensional deposition of calcium phosphate on porous Ti6Al4V

This study developed a 3D deposition technology to form calcium phosphate compounds on the top, interior, and bottom surfaces of a porous Ti6Al4V. The deposition was achieved by laser irradiation of a porous Ti6Al4V in a solution containing Ca and P. The effects of the laser power and specimen thickness on the distribution of deposits were investigated. Under laser irradiation, many petal-like deposits formed directly on the top, interior, and bottom surfaces of the porous Ti6Al4V. Increasing the laser power increased the uniformity of the deposits. The deposits fully covered the porous Ti6Al4V when the laser power was 70 %.

Proposing a new sustainable approach for sand improvement using biologically-derived calcium phosphate cement

Bio-mediated soil improvement methods keep on gaining the attention of geotechnical engineers and researchers globally due to their nature-based elegance and eco-friendliness. Most prevalent bio-mediated soil improvement methods include microbial induced carbonate precipitation (MICP) and enzyme induced carbonate precipitation (EICP). During their processes, the bacteria/ free urease hydrolyzes the urea into ammonium and carbonic acid, which is accompanied by a considerable increase of alkalinity (about pH 9.0). The major problem associated with the above techniques is the release of gaseous ammonia that is extremely detrimental. Therefore, this study aims to propose a new sustainable approach involving lactic acid bacteria to facilitate the calcium phosphate mineralization for the strengthening of sand matrix. The major objectives of this investigation are (i) to evaluate the urease activity of the lactic acid bacteria under different temperatures, pH conditions and additions of metal ions, (ii) to assess the treated sand matrix, (iii) to perform cost analysis. The outcomes indicated that Limosilactobacillus sp. could effectively facilitate the urea hydrolysis, hence increase in pH from acidic to neutral, and provided a desirable environment for the calcium phosphate to mineralize within the voids of the sand. The addition of 0.01% Ni2+ in culture media was found to enhance the urease activity by 38.8% and compressive strength over 40%. A combined formation of amorphous- and whisker-like precipitates could bridge a larger area at particle-particle contact points, facilitated a strong force-network in sand matrix. The mineralized calcium phosphate compound was found to be brushite. The cost herein for producing 1L treatment solution was estimated to be about 2.5-folds and 11.8-folds lower compared to that of MICP and EICP treatment solutions, respectively. Moreover, since the treatment pH could potentially be regulated between acidic – neural range, it would greatly control the release of gaseous ammonia. With several environmental and economical benefits, the study has disclosed a new sustainable direction for sand improvement via the use of lactic acid bacteria.

Ecofriendly solidification of sand using microbially induced calcium phosphate precipitation

This study introduces microbiologically induced calcium phosphate precipitation (MICPP) as a novel and environmentally sustainable method of soil stabilization. Using Limosilactobacillus sp., especially NBRC 14511 and fish bone solution (FBS) extracted from Tuna fish bones, the study was aimed at testing the feasibility of calcium phosphate compounds (CPCs) deposition and sand stabilization. Dynamic changes in pH and calcium ion (Ca2+) concentration during the precipitation experiments affected the precipitation and sequential conversion of dicalcium phosphate dihydrate (DCPD) to hydroxyapatite (HAp), which was confirmed by XRD and SEM analysis. Sand solidification experiments demonstrated improvements in unconfined compressive strength (UCS), especially at higher Urea/Ca2+ ratios. The UCS values obtained were 10.35 MPa at a ratio of 2.0, 3.34 MPa at a ratio of 1.0, and 0.43 MPa at a ratio of 0.5, highlighting the advantages of MICPP over traditional methods. Microstructural analysis further clarified the mineral composition, demonstrating the potential of MICPP in environmentally friendly soil engineering. The study highlights the promise of MICPP for sustainable soil stabilization, offering improved mechanical properties and reducing environmental impact, paving the way for novel geotechnical practices.

Mechanosynthesis and microstructural characterization of F− and CO32− mono- and co-substituted hydroxyapatite

An investigation into the microstructural properties and mechanosynthesis mechanisms of three distinct calcium phosphate compounds, namely, carbonate-substituted hydroxyapatite (CHA), fluorapatite (FA), and carbonate- and fluoride-substituted hydroxyapatite (CFHA), was undertaken in this study. Significant insights into the crystalline structures of CHA, FA, and CFHA were revealed through Rietveld refinement analysis. In the CaCO3‒Ca(OH)2‒P2O5 ternary system, the transformation of the biphasic structure composed of CHA and dicalcium phosphate anhydrous (DCPA) into a single-phase A-type CHA was observed as milling duration increased. In the CaO‒Ca(OH)2‒CaF2‒P2O5 quaternary system, the formation of FA was influenced by milling time, and within 1‒5 h, a composite structure was formed. The progression from a composite structure to the formation of fully crystalline nanosized CFHA was also observed over the same milling periods in the CaCO3‒Ca(OH)2‒CaF2‒P2O5 quaternary system. The central finding highlights the substantial influence of milling time on the structural properties of the mechanosynthesized nanopowders, with marked changes in crystallite size, micro-strain, and unit cell volume being observed over different milling durations. The atomic coordinates and displacement parameters of the refined structures were also provided, revealing the presence of apatitic groups. Moreover, a detailed examination of the mechanochemical synthesis processes uncovered intricate sub-reactions that occur during ball milling. This work sets the stage for future investigations, facilitating a better grasp of their distinctive attributes and potential applications across various domains of regenerative medicine.

Bioinspired poly-dopamine/nano-hydroxyapatite: an upgrading biocompatible coat for 3D-printed polylactic acid scaffold for bone regeneration.

Poly-lactic acid (PLA) has been proposed in dentistry for several regenerative procedures owing to its biocompatibility and biodegradability. However, the presence of methyl groups renders PLA hydrophobic, making the surface less ideal for cell attachment, and it does not promote tissue regeneration. Upgrading PLA with inductive biomaterial is a crucial step to increase the bioactivity of the PLA and allow cellular adhesion. Our purpose is to evaluate biocompatibility, bioactivity, cellular adhesion, and mechanical properties of 3D-printed PLA scaffold coated with poly-dopamine (PDA) and nano-hydroxyapatite (n-HA) versus PLA and PLA/n-HA scaffolds. The fused deposition modelling technique was used to print PLA, PLA with embedded n-HA particles, and PLA scaffold coated with PDA/n-HA by immersion. After matrices characterization for their chemical composition and surface properties, testing the compressive strength was pursued using a universal testing machine. The bioactivity of scaffolds was evaluated by monitoring the formation of calcium phosphate compounds after simulated body fluid immersion. The PLA/PDA/n-HA scaffold showed the highest compressive strength which was 29.11 ± 7.58 MPa with enhancing calcium phosphate crystals deposition with a specific calcium polyphosphate phase formed exclusively on PLA/PDA/n-HA. With cell viability assay, the PDA/n-HA-coated matrix was biocompatible with increase in the IC50, reaching ⁓176.8 at 72 without cytotoxic effect on the mesenchymal stem cells, promoting their adhesion and proliferation evaluated by confocal microscopy. The study explored the biocompatibility, bioactivity, and the cell adhesion ability of PDA/n-HA coat on a 3D-printed PLA scaffold that qualifies its use as a promising regenerative material.

Synthesis and Characterization of Fluorapatite-Copper(II) Oxide with Sol-Gel Method as an Antibacterial Biomaterial

One of the calcium phosphate compounds that can be used as an antibacterial material for coating dental implants is fluorapatite (FAp). This research aims to synthesize FAp at three different sintering temperatures (600, 800, and 1000°C), copper(II) oxide (CuO), and fluorapatite-copper(II) oxide (FAp-CuO) using the sol-gel method, and test the antibacterial properties of the synthesized products. The sol-gel technique proved successful in synthesizing FAp, with optimal results observed at a sintering temperature of 1000°C, achieving a crystallinity level of 90%. Analyses conducted using X-ray diffractometer, Fourier-transform infrared spectrometer, and scanning electron microscope-energy dispersive X-ray spectrometer revealed FAp as the dominating phase, exhibiting Ca/P and P/F ratios of 1.84 and 4.67, respectively. In FAp-CuO, replacing Ca2+ with Cu2+ ions lowered the average crystallite size, crystallinity, and Ca/P ratio. FAp, CuO, and FAp-CuO all displayed antibacterial activities against S. aureus and E. coli, with FAp-CuO having the maximum average inhibitory zone diameters of 0.243 and 1.397 mm, respectively.

Mechanical Grinding of Hydroxyapatite and Its Interaction with Titanium

The development of promising biocompatible composites based on hydroxyapatite with a metallic component is of great interest to researchers. This article describes the synthesis of hydroxyapatite powder by the hydrolytic method and presents the results of mechanical grinding of hydroxyapatite powder. Additionally, in order to study the interaction between titanium and hydroxyapatite powders, the results of their thermal treatment in the temperature range of 600–900 °C are presented. As a result of the hydrolytic method, a powder consisting of Ca5(PO4)3(OH) and CaO phases with a fraction of 400–600 μm was obtained. According to the results of mechanical grinding, it was determined that with an increase in grinding time from 30 to 120 min, the intensive main diffraction lines corresponding to hydroxyapatite decrease. During the thermal treatment of titanium and hydroxyapatite powders, titanium oxidizes forming suboxides and titanium dioxide (TiO2). At higher temperatures, the hydroxyapatite phase disappears from the mixture, and titanium oxide, calcium phosphate compound, and small amounts of calcium titanate and titanium hydrophosphate are present.

Phosphorus recovery from calcium phosphate enriched activated sludge

This study explores the potential of activated sludge from wastewater treatment plants (WWTP) as an alternative source of phosphorus, vital for fertilisers and other products, compared to large-scale phosphorus mining. The research focuses on analysing optimal conditions and the impact of activated sludge characteristics on phosphorus release from calcium phosphate compounds, particularly hydroxyapatite (HAP). Using batch reactor experiments with varying pH and contact time, the results reveal that lower pH values, particularly pH 4, result in higher phosphorus release. The study also finds that calcium, the predominant metal content in activated sludge, plays a vital role in bonding with phosphates and forming new compounds, effectively reducing phosphorus concentration in the solution. Moreover, the VSS/TSS value in the activated sludge has no significant effect on phosphorus release, but interventions occur at high VSS/TSS values. The reaction rate coefficient is calculated at 0.00033/min at pH 4. Overall, this research emphasises the potential of phosphorus recovery from calcium phosphate enriched activated sludge and underscores the importance of optimising pH and considering activated sludge characteristics for efficient phosphorus release.

Effects of the multiscale porosity of decellularized platelet-rich fibrin-loaded zinc-doped magnesium phosphate scaffolds in bone regeneration.

In recent years, metallic ion-doped magnesium phosphate (MgP)-based degradable bioceramics have emerged as alternative bone substitute materials owing to their excellent biocompatibility, bone-forming ability, bioactivity, and controlled degradability. Conversely, incorporating a biomolecule such as decellularized platelet-rich fibrin (d-PRF) on scaffolds has certain advantages for bone tissue regeneration, particularly in enhanced osteogenesis and angiogenesis. The present study focuses on the impact of d-PRF-loaded multiscale porous zinc-doped magnesium phosphate (Zn-MgP) scaffolds on biodegradability, biocompatibility, and bone regeneration. Scaffolds were fabricated through the powder-metallurgy route utilizing naphthalene as a porogen (porosity = 5-43%). With the inclusion of a higher porogen, a higher fraction of macro-porosity (>20 μm) and pore interconnectivity were observed. X-ray diffraction (XRD) studies confirmed the formation of the farringtonite phase. The developed scaffolds exhibited a minimum ultimate compressive strength (UCS) of 8.5 MPa (for 40 Naph), which lies within the range of UCS of the cancellous bone of humans (2-12 MPa). The in vitro assessment via immersion in physiological fluid yielded a higher deposition of the calcium phosphate (CaP) compound in response to increased macro-porosity and interconnectivity (40 Naph). Cytocompatibility assessed using MC3T3-E1 cells showed that the incorporation of d-PRF coupled with increased porosity resulted the highest cell attachment, proliferation, and viability. For further evaluation, the developed scaffolds were implanted in in vivo rabbit femur condylar defects. Radiography, SEM, OTC labelling, and histology analysis after 2 months of implantation revealed the better invasion of mature osteoblastic cells into the scaffolds with enhanced angiogenesis and superior and accelerated healing of bone defects in d-PRF-incorporated higher porosity scaffolds (40 Naph). Finally, it is hypothesized that the combination of d-PRF incorporation with multiscale porosity and increased interconnectivity facilitated better bone-forming ability, good biocompatibility, and controlled degradability within and around the Zn-doped MgP scaffolds.

Impact of Alkaline Immersion Time on Nano-Hydroxyapatite Synthesis from Broiler Eggshells with Electrochemical Method Using Constant Direct Current (CDC)

Calcium phosphate is widely used in biomaterials, especially as a bone substitute. One of the calcium phosphate compounds that is widely used is hydroxyapatite. In biomedical applications, nano-sized hydroxyapatite particles have better bioactivity than coarse crystals. Hydroxyapatite can be synthesized from various sources of calcium and phosphate. Broiler eggshells were chosen as a source of calcium in this study because they have a relatively high calcium content. The method used in the synthesis of nano-hydroxyapatite in this research is the electrochemical method. This research aims to examine the effect of varying NaOH immersion time on the size and structure of calcium phosphate particles produced using an electrochemical method made from chicken egg shells. The synthesis of nano-hydroxyapatite from chicken egg shells was carried out in 4 stages: material preparation, electrolysis, precipitate immersion, and characterization. Nanometer-sized particles can be acquired through an immersion process lasting at least four hours, and it is observed that the longer the duration of immersion, the greater the resemblance of the resulting structure to hydroxyapatite.

Pengamatan morfologi β-tcp yang disintesis dari cangkang kerang hijau

β-Tricalcium Phosphate (β-TCP) is a biomaterial commonly used in dentistry as a bone substitute. β-TCP is a calcium phosphate compound where β-TCP requires a calcium source to be synthesized. The source of calcium could be obtained from green mussel shells because they have high calcium carbonate (CaCO3). The purpose of this study was to determine the effect of sintering temperature on the morphology of β-TCP synthesized from green mussel shells. The method of this research is an exploratory research conducted by knowing the effect of sintering temperature on the morphology of β-TCP synthesized from green mussel shells. The results of the synthesis were tested for characterized with a Scanning Electron Microscope (SEM). In the SEM characterization results, the higher the sintering temperature used in the sample, the more fused and resulting larger particle size. β-TCP with sintering temperature variations of 950℃, 1.000℃, 1.050℃ and 1.100℃ has a morphology consisting of small particles of irregular shape and bonding to each other to form micropores. The conclusion in this study is that the higher the sintering temperature applied, the more the particles coalesce and form larger particles.

Baseline investigation on enzyme induced calcium phosphate precipitation for solidification of sand

Introduction: Bio-cementation processes [namely, microbial induced carbonate precipitation (MICP) and enzyme induced carbonate precipitation (EICP)] have recently become promising techniques for solidifying loose sands. However, these methods release gaseous ammonia to the atmosphere, which is not desirable for real-scale applications. This study aims to propose an enzyme induced calcium phosphate precipitation (EICPP) method as a sustainable direction for the solidification of sand.Methods: Precipitation of calcium phosphate compound (CPC) was driven through pH-dependent mechanism regulated by enzymatic hydrolysis of urea. The baseline study was designed to consist of a series of precipitation tests and sand column tests, evaluating the influence of various recipes of cementation media (CM) on treatment efficiency. The evaluation program consisted of Unconfined compression tests, precipitation content measurement, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction.Results: The observations showed that the content of urea had an important role in proposed EICPP treatment, which determined the extent of the pH increase. This increase had a great influence on 1) utilization of soluble calcium, 2) precipitation content of calcium phosphate, and 3) the morphology of the precipitates. Results of sand column test suggested that injecting CM that consisted of acid-dissolved bone meal, urea and urease enzyme could result in the deposition of insoluble CPC that enabled the solidification of sand particles.Discussion: The precipitation quantity was found to increase with the increase in urea content; however, the treatment media with high urea content resulted amorphous-like crystals. The plate-like crystals were evidenced in CM with [Ca]/[urea] molar ratio between 1.5–2.0. X-ray Diffraction (XRD) analysis revealed that irrespective of the urea contents, the formed crystals were identified as brushite. Since the final pH of proposed EICPP method could be controllable within acidic-neutral conditions, the emission of ammonia gas would be eliminated.

Comparative study of calcium phosphate deposition on nanotubular and sandblasted large grit acid-etched titanium substrates

Titanium and its alloys are widely used in biomedical applications due to their excellent properties such as biocompatibility, good corrosion resistance, low density, and high elastic modulus. However, their bioinert behavior often results in prolonged osseointegration periods. Therefore, surface modification techniques have been investigated to improve the bioactivity of titanium. In this study, the morphological and chemical properties of sandblasted, large grit, acid-etched (SLA), and nanotubular (NT) surfaces were investigated before and after the deposition of calcium phosphate (CaP) compounds by a chemical conversion method. Various techniques were used to characterize these surface modifications applied to titanium, including microhardness tests, atomic force microscopy, water contact angle measurements, scanning electron microscopy, grazing angle X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that the SLA surface was rougher than the NT surface, and the hydrophilic behavior of both samples was enhanced after immersion in NaOH and chemical conversion. The higher concentration of Ca, P, and phosphate functional groups on the NT surface indicates that a greater amount of CaP was deposited on this surface. The CaP-modified NT surface exhibited a favorable surface topography and chemical composition, which may be advantageous for use in titanium dental implants. In addition, in vitro assays showed that the samples prepared here are promising candidates for biomedical use, as they exhibited high cell viability, non-toxicity, and osteogenic properties.

Development of 3D Printable Calcium Phosphate Cement Scaffolds with Cockle Shell Powders.

Three-dimensional (3D) printed calcium phosphate cement (CPC) scaffolds are increasingly being used for bone tissue repair. Traditional materials used for CPC scaffolds, such as bovine and porcine bone, generally contain low amounts of calcium phosphate compounds, resulting in reduced production rates of CPC scaffolds. On the other hand, cockle shells contain more than 99% CaCO3 in the form of amorphous aragonite with excellent biocompatibility, which is expected to increase the CPC production rate. In this study, 3D-printed cockle shell powder-based CPC (CSP-CPC) scaffolds were developed by the material extrusion method. Lactic acid and hyaluronic acid were used to promote the printability. The characterization of CSP-CPC scaffolds was performed using Fourier transform infrared spectra, X-ray diffraction patterns, and scanning electron microscopy. The biocompatibility of CSP-CPC scaffolds was evaluated using cell viability, Live/Dead, and alkaline phosphatase assays. In addition, CSP-CPC scaffolds were implanted into the mouse calvarial defect model to confirm bone regeneration. This study provides an opportunity to create high value added in fishing villages by recycling natural products from marine waste.

Eco-friendly soil stabilization method using fish bone as cement material

The method of soil improvement by calcium phosphate precipitation is a novel, environmentally friendly, and non-toxic technique. Such technology provides advantages over ureolytic induced calcite precipitation (UICP), the most popular and widely used method in the field of geotechnical engineering. In this paper, an investigation of the consolidation of fine and coarse sand samples by enzyme induced calcium phosphate precipitation (EICPP) was carried out. Tuna bones were used as an alternative source of calcium and phosphorus ions, as one of the most popular fish species in Japan and the main source of food industry waste. Unconfined compressive strength (UCS) of the samples after 21 days of daily injection of the solution showed an increase in strength up to 6,05 MPa in fine and up to 4,3 MPa in coarse sand samples. X-ray powder diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (SEM-EDS) analysis were performed to investigate the nature and type of deposition. Analyses confirmed that deposition is composed of brushite with needle-like crystals in the case of Toyoura sand and flower-like crystals in the case of Mikawa sand. SEM-EDS showed a presence of both, calcium, and phosphorus in the precipitate, indicating the presence of calcium phosphate compounds (CPCs). This study reveals that tuna bones are a rich source of calcium and phosphorus for EICPP, which results in a strengthening of silicate soil up to 3.4–6.05 MPa and is able to reduce ammonia emissions by 85.7 % - 97.5 % compared to UICP.

Toxicity test of bioceramic biphasic calcium phospate (BCP) Sr-Ag doping as bone graft in BHK-21 fibroblast cells

Background: Bone graft is a substitute material that is used to assist reconstruction, stabilize the structure and bonds in bone, stimulate the osteogenesis process and as a healing bone defect. One type of bone graft that has good osteoinductive and bicompatibility is alloplast which is a synthetic calcium phosphate compound. The most frequently used Calcium Phosphate groups are Hydroxyapatite (HA), β-Tricalcium Phosphate (β-TCP), and Biphasic Calcium Phosphate (BCP). In this study the material used was BCP doping Sr2+ and Ag+. Strontium ions (Sr2+) can increase osteoblast activity, reduce osteoclast activity and cytokine production, improve osteointegration, and minimize fractures. Ag+ ion has the ability as an antibacterial agent. Purpose: To explain and prove the toxicity of bioceramic Biphasic Calcium Phosphate (BCP) doped Sr-Ag as bone graft on BHK-21 fibroblast cells. Methods: This type of research is a laboratory experiment with a post-test only control group design. Treatment with Biphasic Calcium Phosphate (BCP) doped Sr-Ag with concentrations of 200 ppm, 180 ppm, 160 ppm, 140 ppm, 120 ppm, 80 ppm, 40 ppm, 20 ppm, 10 ppm, 5 pmm, 2.5 ppm, 1.25 ppm, 0.625 ppm in BHK-21 fibroblast cell culture. Results: The percentage of fibroblast cell life at concentrations of 200 ppm, 180 ppm, 160 ppm, 140 ppm, 120 ppm, 80 ppm, 40 ppm, 20 ppm, 10 ppm, 5 pmm, 2.5 ppm, 1.25 ppm, 0.625 ppm, respectively, the percentage of live cells was 38% 44%, 46%, 50%, 52%, 65%, 69%, 71%, 72%, 75%, 77%, 81%, and 87%. The parameter used in this toxicity test is CD50. Conclusion: The results of the toxicity test of bioceramic Biphasic Calcium Phosphate (BCP) doped Sr-Ag as a bone graft showed a toxic and non-toxic effect on BHK-21 fibroblast cells at certain concentrations.

Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L

Calcium phosphate/Bioglass composite coatings on AISI 316L were investigated with regard to their potential role as a beneficial coating for orthopedic implants. These coatings were realized by the galvanic co-deposition of calcium phosphate compounds and Bioglass particles. A different amount of Bioglass 45S5 was used to study its effect on the performance of the composite coatings. The morphology and chemical composition of the coatings were investigated before and after their aging in simulated body fluid. The coatings uniformly covered the AISI 316L substrate and consisted of a brushite and hydroxyapatite mixture. Both phases were detected using X-ray diffraction and Raman spectroscopy. Additionally, both analyses revealed that brushite is the primary phase. The presence of Bioglass was verified through energy-dispersive X-ray spectroscopy, which showed the presence of a silicon peak. During aging in simulated body fluid, the coating was subject to a dynamic equilibrium of dissolution/reprecipitation with total conversion in only the hydroxyapatite phase. Corrosion tests performed in simulated body fluid at different aging times revealed that the coatings made with 1 g/L of Bioglass performed best. These samples have a corrosion potential of −0.068V vs. Ag/AgCl and a corrosion current density of 8.87 × 10−7 A/cm2. These values are better than those measured for bare AISI 316L (−0.187 V vs. Ag/AgCl and 2.52 × 10−6 A/cm2, respectively) and remained superior to pure steel for all 21 days of aging. This behavior indicated the good protection of the coating against corrosion phenomena, which was further confirmed by the very low concentration of Ni ions (0.076 ppm) released in the aging solution after 21 days of immersion. Furthermore, the absence of cytotoxicity, verified through cell viability assays with MC3T3-E1 osteoblastic cells, proves the biocompatibility of the coatings.