SBF Solution Research Articles

Mineralized Biopolymers-Based Scaffold Encapsulating with Dual Drugs for Alveolar Ridge Preservation.

Mineralization of scaffolds is essential for alveolar ridge preservation and bone tissue engineering, enhancing the mechanical strength and bioactivity of scaffolds, and promoting better integration with natural bone tissue. While the in situ mineralization method using concentrated SBF solutions is promising, there is limited comprehensive research on its effects. In this study, it is demonstrate that soaking gelatin/alginate scaffolds (GAS) in fivefold concentrated SBF significantly reduces the mineralization time to 3-7 days but also leads to considerable degradation and loss of the scaffold's original microstructure. The ratio of gelatin to alginate is optimized to improve the properties of GAS. The optimized GAS sample, when soaked in concentrated SBF to form GAS/HAp, exhibited hydroxyapatite (HAp) crystal formation starting from day 3, with mature hexagonal crystals forming by day 7. However, this process also caused significant decomposition and deformation of the scaffold's pore structure. Additionally, the biocompatibility of GAS and GAS/HAp is evaluated through in vitro, in ovo, haemolysis, and anti-ROS assays. The findings highlight the impact of SBF5× on the mineralization of GAS, laying the groundwork for further research in alveolar ridge preservation and bone tissue engineering.

Hydrothermal synthesis of bioactive calcium silicate glass

This work presents the synthesis of bioactive glass 60SiO2-40CaO (wt.%) by the hydrothermal method without using acid catalysts in shortened synthesis time. The precursors Si(OC2H5)4 (TEOS), Ca(NO3)2.4H2O were introduced in a hydrothermal system, and heated at 150 oC for 24 hours. The resulting gel was dried at 150 oC for 24 hours, then calcined at 800 oC for 3 hours to achieve bioactive glass. Several physical-chemical methods such as TG-DSC, XRD, SEM, and ICP-OES were used to evaluate the synthetic material. The bioactivity and biocompatibility of synthetic glass were evaluated by in vitro experiments in SBF solution and in cell culture environment. The obtained results show that the synthetic glass is an amorphous material, presenting the bioactivity through the formation of a hydroxyapatite mineral layer after 10 days of soaking in SBF solution, and also showing good biocompatibility with cells L-929. Keywords: Bioactive glass, bioactivity, artificial bone, hydroxyapatite, cell viability

The effects of ECAP, Mn and Ca elements on the microstructure and corrosion properties of magnesium alloys were investigated

In this study, through reasonable composition design, three elements of Zn, Mn and Ca, which are harmless to human body, were selected for alloying magnesium. The effects of ECAP treatment on the microstructure and corrosion properties of Mg-4Zn-1Mn-0Ca, Mg-4Zn-1Mn-0.2Ca and Mg-4Zn-0Mn-0.2Ca alloys were studied. The corrosion mechanism of Mg-Zn-Mn-Ca alloys with different components in Simulated. Body fluid (SBF) was analyzed by weight loss method and electrochemical test. The grains and the second phase were refined by Equal Angular Channel Pressing (ECAP). It was found that after 8 ECAP deformations, the microstructure of the alloy was refined and more uniform than that of the extruded alloy. The corrosion resistance of the Mg-Zn-Mn-Ca alloy after ECAP deformation in simulated body fluids was studied by electrochemical testing techniques, immersion experiments and observation of the microstructure and morphology of corrosion products. The relationship between microstructure characteristics, the behavior of the magnesium metal matrix and the properties of corrosion products was revealed. The results show that the microstructure of the alloy is refined and the corrosion resistance is improved with the increase in extrusion passes in the SBF solution. The corrosion resistance of magnesium alloy after 8 ECAP deformation is the best, showing small Icorr and large Rt. With the extension of the soaking time, the surface of the alloy will form a passivation film, which will protect the matrix and avoid further corrosion of the alloy. It is found that in SBF, the corrosion of the alloy surface is mainly pitting, which indicates that Ca2+, HCO3- and HPO42- in SBF can reduce the corrosion rate of magnesium alloy.

Fabrication of high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite composites through multi-pass friction stir processing

Magnesium-based composites with bioactive ceramic particles addition are promising materials for biomedical implant applications. Nevertheless, the agglomeration of bioactive ceramic particles remains a challenge for fabricating high-performance biomedical magnesium-based composites. Herein, a novel high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite (HA) composite is successfully fabricated via multi-pass friction stir processing (MP-FSP). Systematic investigations reveal that MP-FSP leads to a uniform distribution of HA particles and efficient elimination of defects. The microstructural analysis shows a significant grain refinement in the WE43 alloy from 49.4 μm to 2.4 μm under triple-passes FSP. The mechanical properties of the composite are enhanced significantly under triple-passes FSP, with yield strength, ultimate tensile strength, and elongation reaching 236.2 MPa, 278.6 MPa, and 14.2% respectively. Corrosion resistance is also improved, with a 30% reduction in the corrosion rate in SBF solution compared to the unprocessed alloy. Moreover, the MP-FSP fabricated composites exhibit superior corrosion-wear resistance, characterized by slight abrasive wear compared to the abrasive wear and severe pitting corrosion observed in the base WE43 alloy. These improvements are attributed to the synergistic effects of grain refinement, dispersion strengthening, enhanced interfacial bonding, and texture modification. Overall, these findings provide significant quantitative insights into the advanced fabrication techniques of magnesium-based composites for biomedical implant applications, highlighting the effectiveness of MP-FSP in enhancing both mechanical and corrosion-related properties.

Износостойкость и коррозионное поведение Cu-Ti-покрытий в растворе SBF

Introduction. Currently, titanium and its alloys have become the most popular metal implantable biomaterials. However, the main disadvantage of titanium alloys is low wear resistance due to high viscosity. It is known that copper-titanium coatings effectively improve the antibacterial properties of titanium alloy and at the same time increase its wear resistance. Purpose of the work is to study the effects of a solution simulating body fluid on corrosion properties, friction coefficient and the wear of copper-titanium coatings obtained by electrospark deposition method of the Ti-6Al-4V alloy. Method. A non-localized electrode consisting of copper and titanium granules in various ratios was used to form copper-titanium coatings on a titanium alloy by electrospark deposition. The structure of the coatings was examined using a DRON-7 X-ray diffractometer in Cu-Kα radiation and an X-max 80 energy dispersive spectrometer. The antibacterial activity of the deposited Cu-Ti coatings was studied on a non-pathogenic gram-negative culture of Escherichia coli. Polarization tests in SBF solution were carried out using a P-40X potentiostat with an impedance measurement module. The metal content in the SBF solution after immersion of the samples was measured using an ICP-MS 2000 mass spectrometer. The tribological characteristics of the coatings according to the ASTM G99-17 standard using the “ball-on-disk” scheme with sliding friction in the SBF solution at loads of 10 and 25 N were examined. Results and discussions. It is shown that the bactericidal activity of Cu-Ti coated samples to a non-pathogenic culture of Escherichia coli increased monotonously with an increase in copper content. With copper concentration increasing, the corrosion current density of the coatings increased from 3.455 to 17.570 μA/cm2. It is shown that the SBF solution accelerates the wear of a titanium alloy many times over due to its interaction with the electrolyte via the oxidative wear mechanism. The use of Cu-Ti coatings allows reducing the friction coefficient and greatly decreasing the wear of Ti-6Al-4V alloy in the presence of an electrolyte.

Optimization of the two-step coating formation process for ZK21 magnesium alloy

Abstract The primary hindrance to the broader utilization of magnesium alloys lies in their insufficient corrosion resistance. This research initiative introduced an advanced two-phase methodology incorporating phosphating and alkali heating to produce a protective Ca-P coating on the surface of magnesium alloys. This innovative approach not only bolsters their corrosion resistance but also facilitates controlled degradation in bodily fluid environments. Following a 60-minute phosphating process in a solution with a pH level of 3, the resultant Ca-P coating achieved full coverage over the magnesium alloy surface, displaying commendable coating density and uniformity. Subsequent treatment with alkali heating for 30 minutes further enhanced the density and smoothness of the coating. Analysis utilizing EDS and XRD revealed that the primary constituents of the phosphate magnesium alloy and the phosphate + alkali heated magnesium alloy coating were DCPD and HA, respectively. Corrosion degradation assessments conducted in SBF solution validated that the two-step coating formation method significantly fortified the corrosion resistance of magnesium alloys.

Silver-doped ZrO2-TiO2 nanocomposite coatings on 316L stainless steel for enhanced corrosion resistance and bio applications

The demand for ceramic based nanocomposite coatings has increased because they play a significant role in orthopedic implants and medical devices. Ceramic nanocomposites are inert and highly biocompatible, which improve corrosion resistance under physiological fluids. The ceramic nanocomposites were deposited (silver-doped ZrO2/TiO2) on SS 316L, and their biocompatibility, strength of adhesiveness, and corrosion resistance properties were studied. A detailed investigation of corrosion resistance, wettability, and biocompatibility concerning microstructures and the inclusion of silver as a dopant was conducted. The deposited films annealed at 600 °C display crystallinity with the coexistence of TiO2 rutile and ZrO2 monoclinic phases. The surface morphology shows the average particle size on thin film is around 40 to 45 nm. The deposited films show a decreased corrosion current density (ICorr) in potentiodynamic polarization curves, confirming the adequate protection against corrosion using simulated body fluid and phosphate buffer saline at 37±1 °C. The surface wettability of coatings is hydrophilic, and it improves in-vitro compatibility. The apatite growth in SBF solution on the implant surface predicts a favorable condition for bone regeneration in the patient's body. The effect of silver dopant on improving apatite growth on implant surface is also discussed. From electrochemical impedance spectroscopy, the diameter of the semicircle in the Nyquist plot shows more than bare metal; the higher the diameter indicates the more resistive behavior of deposited films, which shows the effective corrosion resistance in the electrolytic solution. It is found that the biocompatibility and corrosion resistance are improved compared with bare SS 316L. Hence, ceramic nanocomposite coatings show great potential in the orthopedic implant industry.

Synthesis of Strontium Substituted Hydroxyapatite Coating on Titanium Via Hydrothermal Method

In this study, strontium substituted hydroxyapatite (SrHA) was successfully deposited onto etched titanium substrates in H2SO4 and HCl solution. The deposition was achieved by hydrothermal method by immersing the substrates in a solution containing Ca(NO3)2.4H2O, NH4H2PO4, and 5% Sr(NO3)2, followed by heating at 200°C for 12 hours. X-ray diffraction (XRD) analysis confirmed that all SrHA coatings exhibited a crystalline hydroxyapatite structure. Field-emission scanning electron microscopy (FE-SEM) revealed that the microstructure of the SrHA coatings exhibited. Bioactivity and in vitro biocompatibility testing of the SrHA-coated titanium substrates using SBF solution and baby hamster kidney (BHK) cells demonstrated positive results.

Degradation Behavior of Medical MgZZC-1 in Various Simulated Body Fluids.

Magnesium-based biodegradable metal bone implants exhibit superior mechanical properties compared to biodegradable polymers for orthopedic and cardiovascular stents. In this study, MgZZC-x (x = 1, 1.2) alloys were screened by in vitro biocompatibility tests in three simulated body fluids under nontoxic conditions. The MgZZC-1 alloys with better biocompatibility were selected to predict the days required for complete degradation. The evolution of degradation products was analyzed, and the mechanism of formation of the product film was inferred. A degradation kinetic model was established to investigate the effect of MEM components on the degradation of the alloys. The results demonstrate that the proteins in MEM can greatly retard the degradation progress by attaching to the surface of MgZZC-1 alloys, which are predicted to degrade completely within 341 days. The carbonate and phosphate buffers were adjusted to pH in MEM solution, delaying the degradation of magnesium alloys. This process in MEM more accurately reflects the actual degradation in the body and is superior to that in Hanks and SBF solutions. This study will promote the application of biodegradable materials in clinical medicine.

Mechanical Properties, biodegradable Behavior and biocompatibility of Zn-0.5Ti alloy membranes produced by powder metallurgy for Guided bone regeneration

The Zn-0.5Ti alloy bone regeneration membranes, prepared via powder metallurgy, hot extrusion, and hot rolling, exhibit robust mechanical properties (tensile strength: 122.5 ± 1.8 MPa, elongation: 18.3 ± 0.7 %), appropriate degradation rate (0.127 mm/year in SBF solution), and good biocompatibility (cytotoxicity grade 0–1). After 4 and 8 weeks of implantation, the alloy showed significant bone growth (bone volume ratios (BV/TV): 11.3 ± 1.8 % and 23.1 ± 3.5 %, respectively, measured by Micro-CT), indicating promising potential as a GBR membrane material.

In-vitro biocompatibility, antibacterial activity, and corrosion resistance of HA-TiO2/ZnO coating fabricated by plasma electrolytic oxidation on Ti6Al4V

The hydroxyapatite/Zinc Oxide (HA-TiO2/ZnO) coatings were grown on the Ti6Al4V substrate by plasma electrolyte oxidation from the CaP-based electrolyte containing 1, 3, and 6 g/L ZnO nanoparticles. XRD results confirmed the presence of ZnO, HA, and rutile phases in all coatings. According to SEM observations, coatings presented the porous morphology as a result of micro-arc discharges during the PEO process, whereas some of the pores in the composite coatings were filled by ZnO proportional to its content. After 7 days of immersion in SBF solution, accumulations of bone-like clusters were visible on the surface, demonstrating a promising bio-mineralization ability for all coatings, although the higher amount of 6 g/L ZnO had partially an inhibitory effect on the apatite nucleation. In-vitro studies demonstrated a time and concentration-dependent impact of ZnO on the viability of MG-63 osteoblast-like cells so that the concentration of 3 and 6 g/L caused the death of some cells after 7 days. The antibacterial tests also showcased that the presence of ZnO decreased the activity of gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus), while the higher concentration of ZnO particles led to more antibacterial activity of the coating. Finally, evaluating the corrosion behavior of PEO coatings through a potentiodynamic polarization test in Ringer's solution manifested a better protection against corrosion by increasing the ZnO content in the coating, mainly owing to the blocking of the pores by the ZnO particles, and as a result, the greater difficulty of electrolyte to reach the titanium substrate.

Texturally-enhanced 55S0P and 45S10P Bioactive Glass ceramic particles: Sol-gel fabrication, nano-characterization and comprehensive Bio-evaluation for applications in Bone tissue engineering

Bioactive glass ceramics (BGC) play a pivotal role in bone tissue engineering, specifically addressing challenges associated with bone repair and regeneration. In this study, we developed silica-based 55S0P and 45S10P spherical BGC nanoparticles (NPs), without and with P2O5 content, using a modified Stöber sol-gel process with base hydrolysis. The fabricated spherical NPs with pronounced textural features effectively contribute to enhanced surface roughness, a desirable parameter for improved biological activity in physiologically relevant solutions and tissue matrices. A comprehensive evaluation of the structural properties of these novel spherical BGC-NPs using diverse characterization techniques revealed distinct nano-textural features in the form of cracks and pores. The HR-TEM confirmed the nanoscale dimensions (170–190 nm) of particles with spherical surface morphology and also systematically analysed via DLS, FE-SEM studies. An augmented surface area with mesopores when phosphate added to the silica glass network was revealed by BET analysis. On the biological front, the study records the formation of an HCA layer on the surfaces of the BGC-NPs, the thickness of which increased with an increase in both phosphate content and immersion time (0, 3, 14 & 28 days) in the SBF solution. The zeta potential values attain a maximum from −22 mV to −23.6 mV for 55S0P and −21.5 mV to −26.4 mV for 45S10P BGC-NPs, and improved with increased immersion time, thereby favouring cellular adhesion for desired biological responses. In vitro, cell culture studies on MG-63 cells, after 24 and 72 h of incubation, demonstrated higher cell adhesion and proliferation, with pronounced biocompatibility. In addition, these BGC-NPs exhibited good hemocompatibility even at the highest test concentration (15 mg/ml) and demonstrated effective antibacterial activity against K. pneumoniae and E. coli. A combinatorial analysis of structural and biological properties revealed that the 45S10P BGC-NPs are more potent than 55S0P BGC-NPs for desired biological performances. In conclusion, the results suggest that the sol-gel fabricated BGC-NPs with enhanced nano-textural features are evidently suitable for applications in bone tissue engineering and regenerative medicine.

3D-Printed Polycaprolactone-Based Containing Calcium Zirconium Silicate: Bioactive Scaffold for Accelerating Bone Regeneration.

There is an essential clinical need to develop rapid process scaffolds to repair bone defects. The current research presented the development of calcium zirconium silicate/polycaprolactone for bone tissue engineering utilising melt extrusion-based 3D printing. Calcium zirconium silicate (CZS) nanoparticles were added to polycaprolactone (PCL) porous scaffolds to enhance their biological and mechanical properties, while the resulting properties were studied extensively. No significant difference was found in the melting point of the samples, while the crystallisation temperature points of the samples containing bioceramic increased from 36.1 to 40.2 °C. Thermal degradation commenced around 350 °C for all materials. According to our results, increasing the CZS content from 0 to 40 wt.% (PC40) in porous scaffolds (porosity about 55-62%) improved the compressive strength from 2.8 to 10.9 MPa. Furthermore, apatite formation ability in SBF solution increased significantly by enhancing the CZS percentage. According to MTT test results, the viability of MG63 cells improved remarkably (~29%) in PC40 compared to pure PCL. These findings suggest that a 3D-printed PCL/CZS composite scaffold can be fabricated successfully and shows great potential as an implantable material for bone tissue engineering applications.

Evaluation of bioactivity, biocompatibility, and antibacterial properties of tricalcium silicate bone cement modified with wollastonite/ fluorapatite glass and glass-ceramic

This work's main objective is to assess the effects of wollastonite/fluorapatite glass (G) and glass-ceramic (GC) on tricalcium silicate's (TCS) bioactivity and physico-mechanical properties. To achieve this goal, 10 and 20 wt percent of G or GC were used in place of TCS. The constructed specimens were kept submerged in SBF solution for 4 weeks at a temperature of approximately 37 ± 0.5 °C to create the hydroxyapatite layer (HA) on the cement paste surface and evaluate their biological behavior. Additionally measured were bulk density, apparent porosity, and compressive strength. The principal components had been studied using X-ray diffraction and Fourier transform infrared spectroscopy. An energy dispersive spectroscopy (EDS)-equipped scanning electron microscope (SEM) was used to examine the materials' morphology. The antibacterial and cytotoxic properties were also evaluated. The findings demonstrated that during soaking in SBF, bulk density and porosity ranged from 1.38 to 1.5 g/cm3 and from 44.99 to 39.12 %, respectively, and the results for compression strength varied from 65 to 88 MPa. The outcomes demonstrated that all of the prepared samples' surfaces had the hydroxyapatite layer (HA) formed on them following their immersion in the biological fluid (SBF). Additionally, it was discovered that raising the percentage of GC (TCS/20GC) in synthetic samples improves TCS cement's physico-mechanical and bioactivity characteristics. Furthermore, these substances had minimal cytotoxic effects on the typical fibroplast cell line of humans (BJ1), indicating their potential utility in dental applications. Ultimately, the antimicrobial test demonstrated good inhibitory behavior against the pathogens Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa.

Gelatin- zirconium based metal-organic framework (MOF 801) nanocomposite scaffold for bone tissue engineering

Tissue engineering applications in bone defect treatment have shown promising outcomes over the past decade. In this context, taking advantage of bioactive scaffolds mimicking the intrinsic composition of bone has resulted in remarkable effects on bone regeneration. In this study, Zirconium-based metal-organic framework, known as MOF 801, was synthesized and incorporated into the gelatin matrix as an osteoconductive agent to fabricate a nanocomposite bone scaffold by freeze-drying method. Physical and chemical characteristics of MOF 801 and nanocomposite scaffolds were analyzed using FE-SEM, EDS, XRD, ICP and FTIR. Besides, the biological activity of the prepared scaffolds was evaluated by MTT, alizarin red staining, crystal violet staining, and ALP assays. Inclusion of MOF 801 NPs into the scaffolds resulted in enhancement of their compressive strength up to 15 ± 0.05 MPa. The nanocomposite samples containing MOF 801 NPs also exhibited favorable bioactive feature that was confirmed by their apatite-forming ability on their surfaces upon immersion in SBF solution. The Zr ion and fumarate release studies illustrated sustained release profiles from the gelatin matrix, leading to both antioxidant and anti-inflammatory properties. MTT assay results affirmed biocompatibility of scaffolds containing up to 5 % w/w MOF 801, besides the crystal violet assay exhibited proper cell confluency and adhesion. Eventually, Alizarin red and ALP activity assays revealed that an increment of MOF 801 could induce calcium mineralization and Alkaline Phosphatase enzyme production in MG-63 cells confirming the potential of prepared scaffolds for related bone tissue engineering applications.

Effects of Tb3+ on properties of luminescent calcium sulfate cement

Calcium sulfate powder materials containing terbium ions at 0, 1.0, or 2.0 mol.% were obtained. They are characterized by the presence of a CaSO4 × 0.5H2O phase, while Tb3+ is incorporated into the lattice at ≤1.0 mol.%. Specific surface area enlarged from 2.1 to 22.5 m2/g as crystallite size decreased from 68 to 31 nm. Thermal analysis showed that terbium slightly raises the temperature of CaSO4 × 2H2O-to-CaSO4 transition. Studies of solubility in SBF solution showed the presence of a calcium phosphate layer in terbium-containing cements on the 7th day. Luminescent properties were studied by excitation at 266 nm and 489 nm corresponding to absorption bands of the host and Tb3+ (7F6 - 5D4 absorption band). The recorded emission peaks of the materials showed that the luminescence of the samples was green, with the luminescence intensity increasing when Tb3+ was introduced. The developed materials can find applications in medicine as bioimplants with a possibility of noninvasive visualization of the bone restoration process.

Enhancing bone regeneration: Exploring the potential of silicate chlorinated bioactive glasses and dehydration mechanisms

This study aimed to compare two different compositions of sol-gel method-derived silicate chlorinated bioactive glasses - 45S5 and 58S - and explore the dehydration processes applied (lyophilization, lyophilization+calcination, and calcination). In the synthesis process, sodium metasilicate was used as a silica precursor, and it underwent ion exchange to form silicic acid. The samples underwent characterization through a variety of techniques, assessing their structural properties including Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy, and regarding its bioactivity by the apatite mineralization assay in simulated body fluid. Raman spectroscopy revealed the lyophilization process led to the formation of Q1, Q2, and Q3 silicate structural units for both glasses, but following calcination these reacted to form solely Q2 units - as in the calcined-only glasses. X-ray diffraction analysis confirmed the amorphous nature of the 58S glass, while the 45S5 glass exhibited strong crystalline reflections, including a characteristic peak of sodium chloride. The apatite mineralization assay proved the high bioactivity of the produced glasses. The lyophilized only exhibited rapid hydroxyapatite conversion as a reflection of their structural units containing Q1 structures and of their porous microstructure. The calcined and lyophilized-calcined glasses formed calcium phosphate chloride (Ca2PO4Cl) as an intermediated phase in the glass conversion process. For the 45S5 glass in which both dehydration processes were applied, the intermediated phase led to pH equilibrium of the SBF solution. These findings contribute to the understanding of the structural and compositional properties of silicate chlorinated bioactive glasses synthesized via the sol-gel method. The evaluated glasses show potential for use in bone regeneration applications, with their bioactivity and structural characteristics playing key roles in promoting tissue healing and bonding with bone.

Biodegradation performance of ball burnished magnesium alloy in stimulated body fluids for bioresorbable implant applications

Magnesium alloys are found to be potential bioresorbable materials. However, the application range of these alloys as bioresorbable materials has been limited due to rapid degradation in physiological fluids. The current study deals with the enhancement of degradation behavior of Mg Ze41A alloy in SBF solution by ball burnishing. Further, the influence of burnishing parameters on biodegradation rate has been investigated by Tafel plots, polarization resistance, electrochemical impedance spectroscopy and surface morphology analysis of degraded samples. Additionally, the biodegradation rate has been estimated by ANFIS modeling. The biodegradation rate of Mg Ze41A has been reduced from 1.106 mm/yr to 0.367 mm/yr with an improvement of 68.82% at optimum burnishing condition of burnishing force 50 N, burnishing speed 1400 RPM, burnishing feed 125 mm/min and 2 passes. ANOVA analysis has revealed that burnishing force and feed have contributed the most for the enhancement. The shift in degradation potential towards noble direction and reduction in degradation current density in potentiodynamic polarization curves and the highest charge transfer resistance in electrochemical impedance spectroscopy of the burnished samples are observed for burnished samples. The results reveal that ball burnishing process is a potential surface modification method in reducing the biodegradation rate of Mg Ze41A alloy. The ball burnishing has resulted in lowest biodegradation rate at a degradation current density of 5.743 μA/cm2 and degradation potential of −1.513 V. The ANFIS model developed with 81 fuzzy rules and triangular membership function estimated the biodegradation rate with an accuracy of 95.03%. The decrease in biodegradation rate of ball burnished magnesium substrate in SBF is essentially due to cumulative effect of compressive residual stress, microhardness, surface finish, work hardening and grain refinement.

The role of silica on the superiority of corrosion barrier performance and biological properties of sintered titania-silica composite coating electrophoretically deposited on 316L stainless steel

TiO2 and TiO2–SiO2 composite coatings were electrophoretically deposited on anodized 316L stainless steel substrates and then sintered at 1100 °C. TiO2 coating showed a rutile phase composition involving a cracked surface with a wide diffusion region rich in chromium element near the substrate. While TiO2–SiO2 composite coating showed a crack-free surface with an anatase phase comprising a continuous interlayer. Formation of the dense interlayer prevented the diffusion of substrate elements toward the coating during the sintering and thus inhibited the formation of diffusion region. According to the EIS study after 1 day of immersion in PBS solution, the highest barrier performance belonged to TiO2–SiO2 composite coating where its total faradic resistance (84 MΩ cm2) was 1500 times higher than TiO2 coating and 5.6 times higher than the anodized substrate. This was related to the crack-free surface and the interlayer formed in the composite coating owing to the improving effects of silica. After 28 days of immersion, the total faradic resistance of the TiO2–SiO2 composite coating remained significantly higher (order of 106–107 Ω cm2) than TiO2 coating (∼104 Ω cm2). Furthermore, TiO2–SiO2 composite coating enhanced the apatite formation compared to TiO2 coating or anodized substrate during immersion in SBF solution.

Facial preparation and in vitro bioactivity of rice-like Mg doped CaCO3 particles for bone tissue regeneration

Calcium carbonate (CaCO3) particles with controlled polymorphs, morphologies and specific sizes presented great application potential in biomedical field. In this work, CaCO3 particles with controlled morphologies and surface micro-structure were successfully synthesized by facile and eco-friendly processes. Results revealed that the morphology of CaCO3 could be controlled from spherical to rice-like and dumbbell shaped particles with different surface micro-structure by introducing Mg2+ and adjusting the molar ratio of Mg2+/Ca2+. Herein, the in vitro bio-activity of prepared rice-like CaCO3 particles was investigated by immersion in SBF solution for 1, 3 and 5 days. Moreover, in vitro cyto-compatibility of prepared rice-like CaCO3 particles has also been evaluated by CCK-8 and live/dead staining assay. Results demonstrated that the rice-like CaCO3 particles possess excellent bio-activity and in vitro cyto-compatibility, which suggest the great promise of prepared rice-like CaCO3 particles in bone tissue engineering.