Composites In Simulated Body Fluid Research Articles

Effect of pH and hydroxyapatite-like layer formation on the antibacterial properties of borophosphate bioactive glass incorporated poly(methyl methacrylate) bone cement.

Infection is a leading cause of total joint arthroplasty failure. Current preventative measures incorporate antibiotics into the poly (methyl methacrylate) (PMMA) bone cement that anchors the implant into the natural bone. With bacterial resistance to antibiotics on the rise, the development of alternative antibacterial materials is crucial to mitigate infection. Borate bioactive glass, 13-93-B3, has been studied previously for use in orthopedic applications due to its ability to be incorporated into bone cements and other scaffolds, convert into hydroxyapatite (HA)-like layer, and enhance the osseointegration and antibacterial properties of the material. The purpose of this study is to better understand how glass composition and change in surrounding pH effects the composite's antibacterial characteristics by comparing the incorporation of 30% wt/wt 13-93-B3 glass and pH neutral borophosphate bioactive glass into PMMA bone cement. We also aim to elucidate how HA-like layer formation on the cement's surface may affect bacterial adhesion. These studies showed that 13-93-B3 incorporated cements had significant reduction of bacterial growth surrounding the composite beyond 24h of exposure when compared to a neutral borate bioactive glass incorporated cement (p < 0.01) and cement only (p < 0.0001). Additionally, through soaking cement composites in simulated body fluid and then exposing them to a bioluminescent strand of staphylococcus aureus, we found that the presence of a HA-like layer on the 13-93-B3 or pH neutral glass incorporated cement disks resulted in an increase in bacterial attachment on the composite cement's surface, where p < 0.001, and p < 0.05 respectively. Overall, our studies demonstrated that borate bioactive glass incorporated PMMA bone cement has innate antimicrobial properties that make it a promising material to prevent infection in total joint arthroplasties.

Enhanced biomedical potential of polyurethane/hydroxyapatite composites through chemical modification: A comprehensive study on structure, morphology, and cytocompatibility for tissue regeneration.

Polyurethane/hydroxyapatite (PU/HA) composites are well-known for various biomedical applications. This study reports a chemical approach to improve the interaction between HA and PU matrix. HA was surface-modified with 1,6-hexamethylene diisocyanate (HMDI). First, an isocyanate-modified HA (IHA) was synthesized by hydro-thermal method. Second, IHA was incorporated into a separately synthesized thermoplastic PU by a solvent casting technique. A series of PU/IHA composites was prepared by varying PU᾿s soft and hard segments. The IHA was added to PU (5 and 10 %). The FTIR spectra exhibited characteristic bands of urethane and HA, confirming the synthesis of the composites. XRD study showed the crystallite size of IHA (20 Å) with hexagonal geometry and an amorphous to semicrystalline nature of composites. SEM showed that composites displayed porous and granular morphology. The TGA thermograms of the composites revealed the thermal stability up to 400 °C. The IHA addition considerably improved hydrophilicity and degradation of the composites in simulated body fluid (SBF). MTT assay revealed improved cytocompatibility (> 80 %) of the composites. These results demonstrated an appreciable improvement in structure, morphology, hydrophilicity, degradation, and cytocompatibility of PU/IHA composites by chemical modification of HA. Hence, these composites possess remarkable potential for biomedical applications such as tissue regeneration.

In vitro degradation and dry sliding wear behaviour of AZ31-Sn/Al2O3 nano metal matrix composites in simulated body fluid for biomedical application

In this research, tin was added to the AZ31/2Al2O3 magnesium metal matrix composite to investigate its influence on degradation rate in the presence of simulated body fluid (SBF) and wear behaviour in dry conditions. The AZ31- xSn/2Al2O3 ( x = 0, 2, 4, 6, 8, and 10 wt%) composites were manufactured using the bottom pouring stir casting route. The microstructure of the manufactured AZ31/2Al2O3 and AZ31- xSn/2Al2O3 composites revealed that they were composed of the α-Mg solid solution and the intermetallic compound □-Mg17Al12, which was situated near the grain boundaries. When tin was added, the Sn-rich intermetallic compound Mg2Sn was formed, increasing the volume fraction of the Mg2Sn phase. Compared to AZ31/2Al2O3 composite, the wear test revealed that AZ31/2Al2O3 composites containing Sn particles exhibited a higher ability to generate more stable tribo-layers at higher applied loads, which protected the worn surface and reduced the wear rate. The wear resistance of composites was improved primarily by the behaviour of the tribo-layer in the wear process. The degradation rates (mm/year) of the AZ31 composites were carried out for 72 h in SBF. The degradation rate was reduced when the Sn content in the AZ31/2Al2O3 composite was increased to 6 wt% and then increased with further Sn addition. It was observed that when the amount of Sn particles increases up to 6 wt%, the severity of the degradation decreases.

Effect of Sn Addition on in vitro Degradation and wear Behaviour of AZ31-xSn/1.5TiO2 Composites in Simulated Body Fluid

Effect of Sn Addition on in vitro Degradation and wear Behaviour of AZ31-xSn/1.5TiO2 Composites in Simulated Body Fluid

Electrochemical corrosion behavior of AZ91D magnesium alloy-graphene nanoplatelets composites in simulated body fluids

Magnesium-based materials have received extensive attention as biomedical implant materials due to their good mechanical properties and ability to degrade naturally in vivo. However, the limitation of magnesium-based materials in medical applications is that the corrosion rate is too rapid to maintain the mechanical integrity of implants during bone healing. The electrochemical corrosion behavior of AZ91D magnesium alloy-graphene nanoplatelets (AZ91D-GNPs) composites in simulated body fluid (SBF) solution was investigated. The corrosion behavior was characterized by microscopic observation, dynamic potential polarization and Nyquist diagram. The influence of different GNPs content and different heat treatment on the corrosion behavior of AZ91D magnesium alloy was determined. The results show that the corrosion resistance of AZ91D-GNPs composites is the highest when the content of GNPs is 0.6 wt%, and the corrosion rate is 2.7549 mm/a. In addition, after solution treatment, the corrosion rate is 0.5179 mm/a, which is reduced by 81%. Solution treatment can effectively improve the corrosion resistance of AZ91D-GNPs composites.

Computational modelling of magnesium degradation in simulated body fluid under physiological conditions

Magnesium alloys are highly attractive for the use as temporary implant materials, due to their high biocompatibility and biodegradability. However, the prediction of the degradation rate of the implants is difficult, therefore, a large number of experiments are required. Computational modelling can aid in enabling the predictability, if sufficiently accurate models can be established. This work presents a generalized model of the degradation of pure magnesium in simulated body fluid over the course of 28 days considering uncertainty aspects. The model includes the computation of the metallic material thinning and is calibrated using the mean degradation depth of several experimental datasets simultaneously. Additionally, the formation and precipitation of relevant degradation products on the sample surface is modelled, based on the ionic composition of simulated body fluid. The computed mean degradation depth is in good agreement with the experimental data (NRMSE=0.07). However, the quality of the depth profile curves of the determined elemental weight percentage of the degradation products differs between elements (such as NRMSE=0.40 for phosphorus vs. NRMSE=1.03 for magnesium). This indicates that the implementation of precipitate formation may need further developments. The sensitivity analysis showed that the model parameters are correlated and which is related to the complexity and the high computational costs of the model. Overall, the model provides a correlating fit to the experimental data of pure Mg samples of different geometries degrading in simulated body fluid with reliable error estimation.

Drug delivery and in vitro biological effects of gum ghatti-modified hydroxyapatite nanoporous composites

The present study investigates the influence of gum ghatti (GG) concentration on the porosity of hydroxyapatite (HAP), where the final composite has been tested for the effects of drug delivery, antibacterial activity, and in vitro cytotoxicity. Following the synthesis of GG-HAP composite by a simple chemical precipitation method, the various analyses were employed to understand the crystallinity, morphology, chemical composition, surface functionality and internal bonding, etc. From the comparison of physical properties among the sintered and un-sintered GG-HAP composites and that too with different concentrations of GG (1%, 5%, and 10%), we observed the superior properties for the samples formed from higher GG concentration (10%) with sintering. We observed the lowest crystal size of 30 nm with 95% crystallinity, a surface area of 108 m2/g, a total pore volume of 0.2 mL/g, an average pore diameter of 33 Å for the Sin-10% GG-HAP composite. In addition, the biocompatibility test performed on the Sin-GG-HAP pellet confirmed the in-built bioactivity and biostability of the composites in simulated body fluid. Further, the Naringenin drug delivery profiles confirmed for the stable and controlled release of loaded drug from the Sin-GG-HAP composites (with 1, 5, and 10% of GG). We observed the highest release of 96% from the Sin-10% GG-HAP matrix in just 90 min and T50% of 416 h, and a mean diffusion time period of 459 h. Finally, the antimicrobial (using both gram-positive and gram-negative bacteria) and cytotoxic activities (with the use of healthy normal and diseased cells) of the drug-loaded and un-loaded GG-HAP composites confirm the potential role of the formed Sin-10% GG-HAP composite towards biomedical applications.

Bioglass-fibre reinforced hydroxyapatite composites synthesized using spark plasma sintering for bone tissue engineering

Hydroxyapatite (HA) exhibits several desirable characteristics, but it still lacks osteoinduction, which is a necessary requirement for a bone scaffold. HA-based composites with different amounts of Bioglass? (BG) were prepared using spark plasma sintering (SPS). Careful selection of the SPS parameters avoided undesirable reactions between the calcium phosphate (CaP) and bioglass (BG present in the form of powder and fibres), as confirmed through X-ray diffraction analysis. Scanning electron microscopy images of the composite scaffolds revealed a fibre like appearance of the glassy region. The in vitro bioactivity and biodegradation analyses were performed by immersing the composites in simulated body fluid (SBF) and tris(hydroxymethyl)aminomethane (Tris), respectively. The ability to obtain only the CaP phase and glassy phase with desirable bioactive and biodegradation behaviour, indicated that these SPS scaffolds can be employed as bone scaffolds for clinical trials, after further in vivo analyses.

Biocomposites based on hydroxyapatite matrix reinforced with nanostructured monticellite (CaMgSiO4) for biomedical application: Synthesis, characterization, and biological studies

In this study, a simple and facile strategy was developed for the synthesis of novel hydroxyapatite (HA)/nanostructured monticellite ceramic composites by mechanical method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS) were used to peruse the phase structure, and morphology of soaked ceramic composites in simulated body fluid (SBF). The in vitro bioactivity of HA-based ceramic composites with nanostructured monticellite ranging from 0 to 50 wt% was evaluated via investigating the formation ability of bone-like calcium phosphates in SBF and the effect of obtained extracts from composites dissolution on osteoblast-like G-292 cell line. Moreover, In vitro cytocompatibility of the HA/monticellite ceramic composites was investigated by MTT, cell growth & adhesion and alkaline phosphatase (ALP) activity assays, and quantitative real-time PCR analysis. The results showed that HA/nanostructured monticellite ceramic composites could induce apatite formation in SBF. The cell proliferation and growth exposed to ceramic composites extracts were significantly stimulated and promoted at a certain concentration range compared to control for various time periods of cell culture. The optimized composite extract enhanced considerably gene expression of G-292 type X collagen (COLX) at different days. Also, G-292 cells were spread and adhered well on the ceramic composite disc. Furthermore, ALP activity of G-292 cells exposed to ceramic composites extracts was dramatically enhanced in comparison with pure HA extract (as control) at different concentrations for various time periods of cell culture. The results suggest that the optimized HA/nanostructured monticellite composite is promising biomaterial for clinical applications such as orthopedic and dentistry.

Corrosion resistance and bioactivity of SiO2-Y2O3 coatings deposited on 316L steel

Ceramic coatings consisting of SiO2-Y2O3 layers were deposited on 316L steel using the sol-gel technique. The Y2O3 layer was included to increase the build-up of apatite ceramic, and to improve the corrosion resistance of the steel to bodily fluids. Raman spectra and EDS analysis confirmed the increased presence of Ca and P on the surface of the samples after 220 days of exposure to simulated body fluid (SBF) when compared to three-layer SiO2 coatings. The nucleation of bone-like apatites on the coating surface is indicative of the bioactive effect of the Y2O3 layer. The high corrosion resistance of steel coated with Y2O3 and SiO2-Y2O3 layers was confirmed by the corrosion current densities and ICP-OES analysis of the SBF composition after exposure of the samples.

Biomimetic mineralization and cytocompatibility of nanorod hydroxyapatite/graphene oxide composites

Nanorod hydroxyapatite (NRHA)/graphene oxide (GO) composites with weight ratios of 0.4, 1.5, and 5 have been fabricated by a facile ultrasonic-assisted method at room temperature and atmospheric pressure. The chemical structure properties and morphology of the composites were characterized by field emission source scanning electron microscope, X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The results indicate that the NRHA/ GO composites have an irregular surface with different degree wrinkles and are stable, and NRHA are well combined with GO. In addition, the biomimetic mineralization mechanism of hydroxyapatite on the NRHA/GO composites in simulated body fluid (SBF) is presented. The presence of a bone-like apatite layer on the composite surface indicate that the NRHA/GO composites facilitate the nucleation and growth of hydroxyapatite crystals in SBF for biomimetic mineralization. Moreover, the NRHA- 1.5/GO composite and pure GO were cultured with MC3T3-E1 cells to investigate the proliferation and adhesion of cells. In vitro cytocompatibility evaluation demonstrated that the NRHA/GO composite can act as a good template for the growth and adhesion of cells. Therefore, the NRHA/GO composite could be applied as a GO-based, free-template, non-toxic, and bioactive composite to substitute for a damaged or defect bone.

In vitro bioactivity evaluation of $$\upalpha $$ α -calcium sulphate hemihydrate and bioactive glass composites for their potential use in bone regeneration

To combine the self-setting property of $$\upalpha $$ -calcium sulphate hemihydrate ( $$\upalpha $$ -CSH) with the bioactive property of bioactive glass (BG), BG was added into $$\upalpha $$ -CSH to prepare $$\upalpha $$ -CSH/BG composites. The in vitro bioactivity and cytocompatibility of the $$\upalpha $$ -CSH/BG composites were assessed by soaking the composites in simulated body fluid (SBF) and co-culturing with the osteoblasts, respectively. Formation of a bone-like apatite layer on the composite surface was studied by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Variations in ionic concentration and pH of the SBF solution were detected. The incorporation of BG into $$\upalpha $$ -CSH, effectively compensated for the pH decrease caused by the dissolution of $$\upalpha $$ -CSH and the ion exchange. Osteoblast-like cells (MG63) were cultured on the samples, and the MTT results confirmed that the composites containing BG were more favourable for the proliferation of these cells. Hence, $$\upalpha $$ -CSH/BG composites might have great potential for the use as a bone regeneration material.

In vitro mineralization kinetics of poly(l-lactic acid)/hydroxyapatite nanocomposite material by attenuated total reflection Fourier transform infrared mapping coupled with principal component analysis

Poly(l-lactic acid)/hydroxyapatite (PLLA/HA) nanocomposite, which combines the properties of PLLA and HA, is suitable to construct scaffold for bone tissue engineering. Its mineralization behavior plays a key role in composite’s property. In this present work, two PLLA/HA composites with porous and compact architecture were fabricated and soaked into simulated body fluid (SBF) at 37 °C for in vitro mineralization, respectively. An attenuated total reflection Fourier transform infrared (ATR FTIR) mapping coupled with principal component analysis was developed to investigate the mineralization kinetics. The FTIR images with an area of 300 × 300 μm2 were collected every 7 days. The results suggest that the mineralization of PLLA/HA composites in SBF follows a zero-order kinetic model, no matter what the architecture is. However, it follows a second-order model when the composite is degraded in phosphate-buffered saline solution based on our previous work. The mechanisms of the in vitro mineralization kinetics in different submersion solutions are discussed. Our results alert researchers that they should choose the mineralization medium cautiously.

In simulated body fluid performance of polymorphic apatite coatings synthesized by pulsed electrodeposition

Surface modification is to modify biological responses through changing surface properties without reducing the mechanical properties of the implant. Specifically bioactive coatings, such as hydroxyapatite, carbonate apatite and dicalcium phosphate dehydrate, have been deposited on carbon/carbon (C/C) composites to change the bio-inert surface state. This work focused on the effects of voltages and electrolyte concentrations of pulsed electrodeposition on apatite layer. The apatite coatings thus synthesized were then structurally, morphologically and chemically characterized using X-ray diffraction, scanning electron microscopy, Transmission electron microscopy and Fourier-transform infrared spectroscopy. Remarkably, the voltages and electrolyte concentrations changed the structure, morphology and crystallinity of the obtained coatings. In vitro bioactivity evaluation of polymorphic apatite coatings was performed by soaking the apatite layer coated C/C composites in simulated body fluid (SBF). The corrosion behavior was investigated via the potentiodynamic polarization test in SBF solution. The results confirmed that the increasing deposition voltage and concentration of electrolyte resulted in promoting bioactivity and corrosion resistance by altering the morphologies and phases.

Immunotoxicity evaluation of novel bioactive composites in male mice as promising orthopaedic implants.

ObjectiveIn orthopaedics, novel bioactive composites are largely needed to improve the synthetic achievement of the implants. In this work, semiconducting metal oxides such as SiO2, TiO2, and ZrO2 particles (Ps) were used individually and in different ratios to obtain different biphasic composites. The immunotoxicity of these composites was tested to inspect the potential toxicity prior to their use in further medical applications.Materials and methodsIn vitro mineralisation ability was inspected by soaking the composites in simulated body fluid (SBF). Additionally, in vivo experiments were performed consuming male mice using ISSR-PCR, micronucleus (MN) test, comet assay, glutathione peroxidase activity, and determination of albumin, globulin, lymphocyte population, ALT, and AST levels. Several groups of adult male albino mice were treated with 100, 200, and 400 mg/kg body weight of SiO2, TiO2, and ZrO2-Ps in pure or mixed forms.ResultsOur findings revealed that treatment of mice with low and medium doses of SiO2, TiO2, and ZrO2-Ps in pure or mixed form revealed values relatively similar to the control group. However, using 400 mg/kg especially from TiO2-Ps in genuine form or mixed with SiO2 showed proliferation in the toxicity rates compared with the high dose of SiO2 and ZrO2-Ps.ConclusionsThe results suggest that TiO2 composite induced in vivo toxicity, oxidative DNA damage, bargain of the antioxidant enzymes, and variations in the levels of albumin, globulin, lymphocyte population, ALT, and AST in a dose-dependent manner. However, SiO2, and ZrO2 composites revealed a lower toxicity in mice compared with that of TiO2.

Preparation and characterization of calcium phosphate bone cement with rapidly-generated tubular macroporous structure by incorporation of polysaccharide-based microstrips

Calcium phosphate cements (CPCs) have been extensively used as bone graft substitutes for the repair of bone defect due to its biocompatibility, osteoconductivity and in-situ setting capability. They poorly degrade thus limiting their use in tissue engineering application. A possible strategy to improve the speed of CPC degradation is to add porogen to CPC to create macropores that can enhance cement resorption and can consequently be replaced by new bone. The as-generated macropores are generally not connected because of spherical shape of the porogens which can limit the extent of newly formed bone. The aim of this study was to fabricate CPCs having tubular macroporous structure by incorporating fast-dissolving maltodextrin microstrips (MDMS) and explore their properties such as setting time, mechanical property, microstructure and degradability of the cements. The results showed that after immersing MDMS-embedded composites in simulated body fluid under physiological condition for 1d MDMS rapidly disintegrated (more than 70%), generating tubular macropores in CPCs. The disintegration of MDMS completed in 1 week. CPCs containing MDMS lower than 30% by weight had the same final setting time as those without MDMS. The average values of compressive strength of the CPC composites decreased with the disintegration of MDMS. % Porosity and pore interconnectivity increased with increasing MDMS content. In addition, MDMS-embedded CPCs were cell friendly with excellent cell adhesion, indicating a possible candidate as bone graft substitutes.

Dynamic mechanical properties of carbon fibre-reinforced PEEK composites in simulated body-fluid

The work presents the fatigue mechanical properties of a composite material made of polyetheretherketone (PEEK) polymer and carbon fibres (CF) designed for structural biomaterials. Composite samples with various types of carbon fibre reinforcements were studied. The mechanical durability of the composite samples in simulated body solution was analysed. The samples were loaded for a predetermined number of cycles for various applied-force levels, at a frequency of 50Hz under a bending force, and at 1Hz under compression force. The mechanical changes were analysed taking into consideration the anisotropic structure of the composite samples made of fibre roving 1D, 2D tissue and carbon fibres in the form of braided fibre sleeves (MD). The ultrasonic method was applied to determine the changes in velocities measured in the composites. The average variations of mechanical stability of the composite samples kept in simulated body fluid were not significant after fatigue testing up to 1*106 cycles.

A correlative spatiotemporal microscale study of calcium phosphate formation and transformation within an alginate hydrogel matrix.

The modification of soft hydrogels with hard inorganic components is a method used to form composite materials with application in non-load-bearing bone tissue engineering. The inclusion of an inorganic component may provide mechanical enhancement, introduce osteoconductive or osteoinductive properties, or change other aspects of interactions between native or implanted cells and the material. A thorough understanding of the interactions between such components is needed to improve the rational design of such biomaterials. To achieve this goal, model systems which could allow study of the formation and transformation of mineral phases within a hydrogel network with a range of experimental methods and high spatial and time resolution are needed. Here, we report a detailed investigation of the formation and transformation process of calcium phosphate mineral within an alginate hydrogel matrix. A combination of optical microscopy, confocal Raman microspectroscopy and electron microscopy was used to investigate the spatial distribution, morphology and crystal phase of the calcium phosphate mineral, as well as to study transformation of the mineral phases during the hydrogel mineralization process and upon incubation in a simulated body fluid. It was found, that under the conditions used in this work, mineral initially formed as a metastable amorphous calcium phosphate phase (ACP). The ACP particles had a distinctive spherical morphology and transformed within minutes into brushite in the presence of brushite seed crystals or into octacalcium phosphate, when no seeds were present in the hydrogel matrix. Incubation of brushite-alginate composites in simulated body fluid resulted in formation of hydroxyapatite. The characterization strategy presented here allows for non-destructive, in situ observation of mineralization processes in optically transparent hydrogels with little to no sample preparation. The precipitation and transformations of calcium phosphates (CaP) is a complex process, where both formation kinetics and the stability of different mineral phases control the outcome. This situation is even more complex if CaP is precipitated in a hydrogel matrix, where one can expect the organic matrix to modulate crystallization by introducing supersaturation gradients or changing the nucleation and growth kinetics of crystals. In this study we apply a range of characterization techniques to study the mineral formation and transformations of CaP within an alginate matrix with spatiotemporal resolution. It demonstrates how a detailed investigation of the mineral precipitation and transformations can aid in the future rational design of hydrogel-based materials for bone tissue engineering and studies of biomineralization processes.

Preparation and bioactive properties of nano bioactive glass and segmented polyurethane composites.

Composites of glutamine-based segmented polyurethanes with 5 to 25 wt.% bioactive glass nanoparticles were prepared, characterized, and their mineralization potential was evaluated in simulated body fluid. Biocompatibility with dental pulp stem cells was assessed by MTS to an extended range of compositions (1 to 25 wt.% of bioactive glass nanoparticles). Physicochemical characterization showed that composites retained many of the matrix properties, i.e. those corresponding to semicrystalline elastomeric polymers as they exhibited a glass transition temperature (Tg) between -41 and -36℃ and a melting temperature (Tm) between 46 and 49℃ in agreement with X-ray reflections at 23.6° and 21.3°. However, with bioactive glass nanoparticles addition, tensile strength and strain were reduced from 22.2 to 12.2 MPa and 667.2 to 457.8%, respectively with 25 wt.% of bioactive glass nanoparticles. Although Fourier transform infrared spectroscopy did not show evidence of mineralization after conditioning of these composites in simulated body fluid, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray microanalysis showed the formation of an apatite layer on the surface which increased with higher bioactive glass concentrations and longer conditioning time. Dental pulp stem cells proliferation at day 5 was improved in bioactive glass nanoparticles composites containing lower amounts of the filler (1-2.5 wt.%) but it was compromised at day 9 in composites containing high contents of nBG (5, 15, 25 wt.%). However, Runx2 gene expression was particularly upregulated for the dental pulp stem cells cultured with composites loaded with 15 and 25 wt.% of bioactive glass nanoparticles. In conclusion, low content bioactive glass nanoparticles and segmented polyurethanes composites deserve further investigation for applications such as guided bone regeneration membranes, where osteoconductivity is desirable but not a demanding mechanical performance.

Strontium and magnesium substituted dicalcium phosphate dehydrate coating for carbon/carbon composites prepared by pulsed electrodeposition

Trace elements substituted apatite coatings have received a lot of interest recently as they have many benefits. In this work, strontium and magnesium substituted DCPD (SM-DCPD) coatings were deposited on carbon/carbon (C/C) composites by pulsed electrodeposition method. The morphology, microstructure, corrosion resistance and in vitro bioactivity of the SM-DCPD coatings are analyzed. The results show that the SM-DCPD coatings exhibit a flake-like morphology with dense and uniform structure. The SM-DCPD coatings could induce the formation of apatite layers on their surface in simulated body fluid. The electrochemical test indicates that the SM-DCPD coatings can evidently decrease the corrosion rate of the C/C composites in simulated body fluid. The SM-DCPD has potential application as the bioactive coatings.