Immersion In SBF Research Articles

Physicochemical Characterization of Nanohydroxyapatite Powder in Simulated Body Fluid Immersion: A Pilot Study

Nanohydroxyapatite (n-HA) has been widely used as a bone graft material. In contact with biological fluids, n-HA should be reactive, resorbable, form an bone-like apatite layer on their surfaces, and enhance osseointegration. The release of Ca, P, and O in SBF predicted the formation of bone-like apatite layer. Therefore, this study aims to investigate the physicochemical properties of nano-HA powder during the SBF immersion in vitro. The n-HA powder was immersed in SBF for 24, 48 hours, 7, 14, and 28 days. The swelling ratio, pH, FTIR, and SEM-EDX were analyzed pre- and post-SBF immersion. The n-HA powder showed excellent hydrophilicity and a stable pH, even though there was a pH decrease in 28 days. The carbonate and phosphate functional groups were found through FTIR, in line with the ion composition changes and increase of the Ca/P ratio shown on EDX. Both mean weight percentages (%) of Ca and P increased during 14 days of SBF immersion (16.15 to 27.27; and 8.57 to 11.68, respectively). The other functional groups on the n-HA are PO3 −, CO2 −, O-H, C=H, and COO. In conclusion, the n-HA powder presents good physicochemical properties that indicate the formation of an apatite bonelike layer and is promising as a bone graft material.

Aqueous electrophoretic deposition of yttrium-doped nanobioactive glass/collagen/chitosan orthopedic coatings on 316L SS

The current study used yttrium-doped nanobioactive glass (Y-nBG), based on 62 SiO2 – (33 – x) CaO – 5 P2O5 – x Y2O3 mole % system (x = 0 and 3 mol %), collagen, and chitosan composites for coating 316L stainless steel (316L SS) using aqueous electrophoretic deposition (EPD) technique. The corresponding coated samples are encoded as SS/Col-Chit, SS/BG-Y0/Col-Chit, and SS/BG-Y3/Col-Chit, respectively. Physicochemical characterization implied TGA, FTIR, SEM-EDX, contact angle, adhesion strength and in vitro bioactivity in SBF were performed. Following SBF immersion, FTIR and SEM-EDX investigations were also carried out. Furthermore, the coatings were loaded with gentamicin drug; the drug-release profile and mechanism were evaluated. The antibacterial efficacy of the composite coatings was also assessed. The results showed the formation of homogeneous coatings with good adhesion strength, 1.39 MPa, 0.55 MPa, and 0.81 MPa, and enhanced the wettability by decreasing the contact angle 36⁰, 22⁰ and 12⁰ for SS/Col-Chit, SS/BG-Y0/Col-Chit and SS/BG-Y3/Col-Chit coatings, respectively. In vitro bioactivity of coatings containing nBG revealed apatite formation after immersion in SBF. Furthermore, the antibiotic gentamicin showed a sustained release profile over time by diffusion mechanisms based on the Higuchi, Fickian, and Weibull models. As well, all coatings containing drugs have an antibacterial effect. Overall, these findings suggested that the prepared coatings have potential applications as orthopedic and dental implants.

Magnesium borate-glasses for biomedical application: Physicochemical and in vitro bioactive properties, antibacterial activity and cell viability

Borate bioactive glasses doped with magnesium oxide (MgO) were synthetized by melt-quenching method and evaluated their physicochemical and in vitro bioactive properties. The glasses were characterized by volumetric density, DTA, XRD and FTIR techniques. In vitro bioactivity was evaluated by SBF immersion test. Cytocompatibility tests were performed on RAW-247 murine macrophage cells. Antibacterial activity was evaluated by the agar disk diffusion method. The XRD results confirm the amorphous nature of the glasses. FTIR analysis showed that the MgO addition modifies the glass network, causing changes in the volumetric density, molar volume, and thermal properties. The in vitro bioactivity was confirmed by XRD, FTIR, and SEM-EDS analyses; all samples showed the formation of biological apatites. All samples are non-cytotoxic and presented good antibacterial activity against S. aureus and P. aeruginosa bacteria. Therefore, all samples are good candidates for biomedical applications, mainly in bone regeneration.

Duplex Fluorinated and Atomic Layer Deposition-Derived ZrO2 Coatings Improve the Corrosion Resistance and Mechanical Properties of Mg-2Zn-0.46Y-0.5Nd (wt.%) Alloy Plates and Screws.

This study investigated the corrosion resistance and mechanical properties of Mg-2Zn-0.46Y-0.5Nd (wt.%) alloy plates and screws with fluorinated coatings and atomic layer deposition (ALD)-derived zirconia (ZrO2) coatings in vitro under physiological stress conditions. Synthetic polyurethane hemimandible replicas were split and fixed as the following three groups of magnesium alloy plates and screws: no additional surface coating treatment (Group A), with fluorinated coatings (Group B), and with duplex fluorinated and ALD-derived 100 nm ZrO2 coatings (Group C). A circulating stress of 1-10 N was applied to the distal bone segment, and a 4-week simulated body fluid immersion test was employed to study the remaining material volume and the mechanical properties of the different groups. Compared with Group A and Group B, the degradation rate of magnesium alloy plates and screws' head regions was significantly slowed down under the protection of duplex MgF2/ZrO2 coatings (p < 0.01). There was no significant difference in the degradation rate of the screw shaft region between groups (p = 0.077). In contrast to fluoride coatings, duplex MgF2/ZrO2 coatings maintained the mechanical strength of magnesium alloy plates and screws after a 14 day in vitro SBF immersion test. We conclude that duplex MgF2/ZrO2 coatings exhibited a certain protective effect on the Mg alloy plates and screws under physiological stress conditions.

In vitro Biomineralization Ability of Magnesium-Doped Coral Hydroxyapatite Coating Prepared by Pulsed Laser Deposition

Coral hydroxyapatite (CHA) is a calcium phosphate that has a similar inorganic composition to human bone and the porous structure of coral stone. Due to its interconnected network like pore structure, it can serve as a framework for bone conduction. In this study, CHA films and Mg-CHA films were deposited on titanium and silicon substrates by Pulsed laser deposition, and then the films were heat treated respectively. Studies on the adhesion of the coating showed that the heat-treated Mg-CHA film adhered better to the titanium substrate. The experimental study on biomineralization in vitro showed that a small amount of porous structure appeared in the heat-treated Mg-CHA after immersion in SBF for three days, and the porous structure was visible after immersion for seven days. After 14 days, a new apatite layer formed on the surface. This suggested that magnesium undergoes chemical corrosion in SBF, leading to rapid ion exchange, which results in the formation of porous structures and promotes the development of an apatite-like layer. In summary, the heat-treated Mg-CHA films had superior biomineralization properties.

Zinc oxide coating impact on corrosion of ZK60 magnesium alloys in simulated body fluid

Magnesium alloys offer an alternative for applications in biodegradable implant devices within human body, eliminating the need for subsequent surgeries to remove metallic parts. Nevertheless, the uniform degradation rate of magnesium (Mg) alloys must be enhanced by applying surface coatings, preferably incorporating bactericidal and biocompatible agents, to improve the implant properties. In this study, magnesium alloys ZK60 (Mg, Zn, and Zr) and ZK60-Mm (Mg, Zn, and Zr with 1.5 % mass of rare-earth elements - mischmetal), both having a specific mass close to the bone, were investigated. The surfaces were coated with ZnO using physical vapor deposition (PVD) in the HiPIMS (High Power Impulse Magnetron Sputtering) mode. The corrosion resistance and degradation of the alloys were studied using electrochemical and immersion tests in simulated body fluid. Surface analysis and microstructures were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and X-ray Diffraction (XRD). The results showed that the ZnO coating favors osseointegration with hydroxyapatite formation after immersion in SBF. Moreover, electrochemical analysis indicates an enhancement in corrosion resistance. On average, the corrosion current density decreases by a factor of four for the ZK60 alloy and two for the ZK60-Mm alloy post-coating. The corrosion rate of ZnO-coated alloys is lower compared to that of uncoated alloys, showcasing the promising utility of this coating.

Bioactivity and Antibacterial Analysis of Plasticized PLA Electrospun Fibers Reinforced with MgO and Mg(OH)2 Nanoparticles.

In this work, we focused on the bioactivity and antibacterial behavior of PLA-based electrospun fibers, efibers, reinforced with both MgO and Mg(OH)2 nanoparticles, NPs. The evolution of PLA-based efibers was followed in terms of morphology, FTIR, XRD, and visual appearance. The bioactivity was discussed in terms of hydroxyapatite growth after 28 days, considered as T28, of immersion in simulated body fluid, SBF. In particular, the biomineralization process evidenced after immersion in SBF started at T14 in both systems. The number of precipitated crystals increased by increasing the amount of both NPs. The chemical composition of the precipitated crystals was also characterized in terms of the Ca/P molar ratio after T28 of immersion in SBF, indicating the presence of hydroxyapatite on the surface of both reinforced efibers. Moreover, a reduction in the average diameter of the PLA-based efibers was observed, reaching a maximum reduction of 46 and 60% in the average diameter of neat PLA and PLA:OLA efibers, respectively, after 28 days of immersion in SBF. The antibacterial behavior of the MgO and Mg(OH)2 NPs in the PLA-based electrospun fibers was tested against Escherichia coli, E. coli, as the Gram-negative bacteria, and Staphylococcus aureus, S. aureus, as the Gram-positive bacteria, obtaining the best antibacterial activity against the Gram-negative bacteria E. coli of 21 ± 2% and 34 ± 6% for the highest concentration of MgO and Mg(OH)2 NPs, respectively.

Osteogenic potential of adipose stem cells on hydroxyapatite-functionalized decellularized amniotic membrane

Amniotic membrane (AM) is an attractive source for bone tissue engineering because of its low immunogenicity, contains biomolecules and proteins, and osteogenic differentiation properties. Hydroxyapatite is widely used as bone scaffolds due to its biocompatibility and bioactivity properties. The aim of this study is to design and fabricate scaffold based on hydroxyapatite-coated decellularized amniotic membrane (DAM-HA) for bone tissue engineering purpose. So human amniotic membranes were collected from healthy donors and decellularized (DAM). Then a hydroxyapatite-coating was created by immersion in 10X SBF, under variable parameters of pH and incubation time. Hydroxyapatite-coating was characterized and the optimal sample was selected. Human adipose-derived mesenchymal stem cell behaviors were assessed on control, amniotic membrane, and coated amniotic membrane. The results of the SEM, MTT assay, and Live-Dead staining showed that DAM and DAM-HA support cell adhesion, viability and proliferation. Osteogenic differentiation was evaluated by assessment of alkaline phosphatase activity and expression of osteogenic markers. Maximum gene expression values compared to control occurred in 14 days for alkalin phosphatase, while the highest values for osteocalcin and osteopontin in 21 days. These gene expression values in DAM and DAM-HA for alkalin phosphatase is 6.41 and 8.47, for osteocalcin is 3.95 and 5.94 and for osteopontin is 5.59 and 9.9 respectively. The results of this study indicated DAM supports the survival and growth of stem cells. Also, addition of hydroxyapatite component to DAM promotes osteogenic differentiation while maintaining viability. Therefore, hydroxyapatite-coated decellularized amniotic membrane can be a promising choice for bone tissue engineering applications.

The Structural, Thermal and Morphological Characterization of Polylactic Acid/Β-Tricalcium Phosphate (PLA/Β-TCP) Composites upon Immersion in SBF: A Comprehensive Analysis.

Biocomposite films based on PLA reinforced with different β-TCP contents (10%, 20%, and 25%wt.) were fabricated via solvent casting and immersed in SBF for 7, 14, and 21 days. The bioactivity, morphological, and thermal behavior of composites with immersion were studied using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, weight loss (WL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). This broad analysis leads to a deeper understanding of the evolution of the polymer-filler interaction with the degradation of the biocomposites. The results showed that β-TCP gradually evolved into carbonated hydroxyapatite as the immersion time increased. This evolution affected the interaction of β-TCP with PLA. PLA and β-TCP interactions differed from PLA and carbonated hydroxyapatite interactions. It was observed that β-TCP inhibited PLA hydrolysis but accelerated the thermal degradation of the polymer. β-TCP retarded the cold crystallization of PLA and hindered its crystallinity. However, after immersion in SBF, particles accelerated the cold crystallization of PLA. Therefore, considering the evolution of β-TCP with immersion in SBF is crucial for an accurate analysis of the biocomposites' degradation. These findings enhance the comprehension of the degradation mechanism in PLA/β-TCP, which is valuable for predicting the degradation performance of PLA/β-TCP in medical applications.

Polymer-derived Biosilicate-C composite foams: In-vitro bioactivity, biocompatibility and antibacterial activity

Biosilicate/carbon composites were fabricated in the form of highly porous foams by the polymer-derived ceramic route, and their biological response was analysed. Two different commercial silicone polymers (a poly-methyl-siloxane, MK, and a polymethyl-phenyl-silsesquioxane, H44) were considered as a silica source, mixed with active fillers yielding Na2O, CaO and P2O5. The samples were heat treated either in air or in N2 atmosphere to obtain products resembling the known Biosilicate® glass-ceramic, with or without free carbon. All fabricated samples exhibited acellular in-vitro bioactivity upon immersion in SBF as well as antibacterial activity against S. aureus and E. coli. Direct contact cell viability test, assessed by using a WST-8 assay, indicated that both carbon-containing and carbon-free samples were cytocompatible.

Mechanical and biological properties of Ti–15%Mo-Cenosphere porous composite sintered by SPS

Decreasing the sheath stresses and facilitating osteogenesis are of great interest in the preparation of orthopedic implants. For this reason, the fabrication of porous composite samples based on Ti alloys is of great importance in the medical industry. This research is dedicated to investigating the mechanical and biological properties of porous composite samples prepared by powder metallurgy, space holder technique, and sintering using Spark Plasma Sintering (SPS). According to the results obtained, it was found that owing to an increase in the volume percentage of the space holder, the density of the samples decreased while the true porosity percentage of the samples increased. The morphology of the pores formed in the structure was spherical with a uniform distribution. In addition, it was found that the elastic modulus of the sample decreased significantly so that the samples containing >30 vol% cenosphere space holder exhibited properties similar to those of bones. Also, according to the results of the MTT, SBF immersion, and cell adhesion tests, it was concluded that the samples were of high cell viability. Moreover, the growth and proliferation of bone cells and the formation of apatite crystals using these composites were confirmed.

Devitrite (Na2Ca3Si6O16) phase dominated nanostructured 45S5 bioactive glass: exploring its structural and biological properties

This research study is primarily centred around calcination temperature and time influence on phase formation in bioactive glasses (BGs). In the present study, BG with a nominal composition of 45S5 was synthesized through the sol–gel process. The developed BGs then underwent heat treatment for various sintering durations and temperatures. X-ray diffraction (XRD) patterns of the BGs reveals that the sintering process led to the crystallization of both devitrite (Na2Ca3Si6O16) and combeite (Na2Ca2Si3O9) phases. The field emission scanning electron microscopy study divulges morphological alterations, from sheet-like to rod-like structures to eventually transforming into spherical and sheet-like structures. The surface area and Type-IV mesoporous porosity were validated through Brunauer Emmett Teller analysis, highlighting a notable increase in pore volume and mechanical strength at a lower sintering temperature. In vitro apatite formation was carried out in Hank’s balance salt in order to evaluate the bioactivity of the glass. After 7 d of immersion in simulated body fluid (SBF), XRD patterns and scanning electron microscopy micrographs results showed that formation of hydroxyapatite layer on the surface of the BGs. The BG compatibility with erythrocytes (red blood cells) was also studied, and the results revealed that there was only a low 2% lysis, showing good hemocompatibility. The drug loading and release behaviour of the BGs was studied in the in vitro analysis. The findings showed a high drug encapsulation effectiveness of up to 90% and continuous drug release from the BGs for 24 h. The materials biocompatibility was unambiguously confirmed by cytocompatibility and proliferation studies. This study provides compelling evidence for the exceptional efficacy and promise of the distinct 45S5 BGs in advancing the field of regenerative medicine.

Improvement in Tensile Strength of Mg Alloy After Immersion in SBF by Cold-Sprayed Zn Coating

Improvement in Tensile Strength of Mg Alloy After Immersion in SBF by Cold-Sprayed Zn Coating

Fabrication of bioactive glass/phosphorylated chitosan composite scaffold and its effects on MC3T3-E1 cells

This study aimed to synthesize bioactive glass (BG) and phosphorylated chitosan (PCS), and fabricate a BG/PCS composite scaffold. The physical properties (mechanical strength, swelling degree, and degradation rate) of the BG/PCS scaffold were tested. The in vitro mineralization properties of composite scaffolds in simulated body fluid were investigated. MC3T3-E1 cell responses with the BG/PCS scaffold were investigated using live/dead cell staining, actin staining, alkaline phosphatase (ALP) activity, and Alizarin red staining. Our results showed that the scaffold had an inner porous structure, good swelling properties, and good degradation rate. After immersion in SBF, the scaffolds demonstrated high properties in inducing mineralization. Leaching solutions of the composite scaffolds exhibited good cytocompatibility. MC3T3-E1 cells adhered, spread, and proliferated on the scaffold. The BG/PCS composite scaffold showed osteo-inductive activity by increasing ALP activity and calcium deposition. Our results indicated that the BG/PCS scaffold had potential applications as a bone-defect repair biomaterial.

Mg ZX10 alloy for biomedical applications: Surface characterization and comparative corrosion studies under simulated biological conditions

Biodegradable magnesium (Mg)-based alloys emerge as potential intracorporeal implants for clinical application in bone tissue, the cardiovascular and the nervous systems. The surfaces of control (non-sterilized) and sterilized (180 °C 1 h) Mg ZX10 alloy were studied. The alloy evolution in SBF (simulated saline solution) and in DMEM (Dulbecco's Modified Eagle Medium) with fetal calf serum (FCS) was investigated using: Raman spectroscopy, FTIR-ATR, electrochemical assays and scanning electron microscopy (SEM). The Mg ZX10 microstructure analysis revealed an average grain size of 23.4 ± 11.02 and 31.6 ± 13.07 μm, considering the minor and major axis, respectively. In addition, the Mg ZX10 microstructure exhibited a homogeneous grain distribution. The contact angle formed between the water and the surface of control Mg ZX10 and sterilized were 32.24° ± 1.53 and 46.76° ± 0.83, respectively. Consequently, both groups of samples exhibited hydrophilic surfaces. Furthermore, the free surface energy of control Mg ZX10 was 63.23 ± 0.72 mN/m and sterilized Mg ZX10 was 52.31 mN/m ± 1.25, those energy values were in agreement with previous reports. Upon immersion in SBF, Raman spectroscopy detected the presence of magnesium oxides-hydroxides, phosphates and carbonates compounds in both groups of samples without significant differences. FTIR spectra of the sterilized alloys, after immersion in DMEM + FCS, showed the presence of amide and carbon-carbon bonds, magnesium-oxides, as well as phosphates and carbonates groups. These findings suggested the deposition of organic and inorganic compounds on the alloy surface. Electrochemical assays carried out in SBF demonstrated a slight reduction in the degradation of the sterilized alloy compared to control Mg ZX10. Moreover, a substantial decrease in the corrosion behavior of the sterilized alloy immersed in DMEM + FCS with respect to the same alloy immersed in SBF was observed. SEM images showed that the alloy, previously immersed in SBF, exhibited degradation cracks. Contrary, the sterilized alloy surface immersed in DMEM + FCS was more homogenous with deposits of structures similar to hybrid nanoflowers. Based on these results, this sterilization process does not alter the chemistry of Mg ZX10 alloy surface and, even, its application exhibits an advantage since the high corrosion rate of Mg in physiological media. Furthermore, the organic-inorganic structures adsorbed, after alloy immersion in DMEM + FCS, could decrease corrosion behavior.

Improving the physical and optical characteristics of Zinc doped borate glass for bone replacement

The presented study explores the potential of zinc-doped modified borate glass as a biomaterial for bone bonding applications. The glass samples were prepared using a melt quenching technique with a definite composition of (45-x) B2O3–24.5Na2O–24.5CaO–6P2O5–xZnO, where x = 1, 2, 5, 7.5, and 10 (wt.%) and soaked in SBF for extended periods to explore their suitability for bone bonding applications. XRD and FTIR analysis were used to examine the structural properties of the samples before and after immersion in SBF. XRD analysis of the prepared samples reveals their amorphous nature before immersion. However, after four weeks of immersion, the XRD spectra show a reduction in the broad band observed at 2θ angles between 20 and 35°, indicating increased crystallization and the formation of a HA layer. FTIR data demonstrates significant modifications in the spectra after immersion, including the disappearance of certain bands and an increase in bands related to (BO4) units. Additionally, the appearance of a new band at approximately 561 cm−1 confirms the formation of crystalline apatite. SEM images confirm the morphological changes, with a transition from a rough surface to a cotton shape, indicative of apatite formation. Electronic spectrum measurements (UV/Vis) were used to assess the samples' optical characteristics, showing that increasing Zn content decreases the optical energy gap, indicating improved optical properties. These findings highlight the structural, morphological, and optical changes induced by zinc ion doping and immersion in SBF, making it a more viable option for bone replacement.

Investigation of Porous Ceramic Structures Based on Hydroxyapatite and Wollastonite with Potential Applications in the Field of Tissue Engineering

Bioceramics are the most promising materials used for hard tissue reconstruction. In this study, wollastonite/hydroxyapatite (HAp/WS)-type composite ceramic structures were synthesized with the aim of reaching a material with improved properties for use in bone tissue regeneration. The scaffolds were synthesized using a foam replica method, starting from ceramic powders with different mass ratios. These were subsequently studied and compared to identify the ideal mass ratio in terms bioactive character, appropriate mechanical properties, but also microstructural influence. The results indicate that all of the samples showed a highly porous microstructure with interconnected pores and high mineralization after 21 days of immersion in SBF. The porous structures with 90% and 70% mass contents of hydroxyapatite presented a well-defined structure and the highest values of mechanical compressive strength. Biocompatibility evaluation showed that osteoblast-like cells are able to penetrate the inner volume of the structures, exhibiting a biocompatible behavior in terms of morphological features and viability following 7 days of incubation. All results show that the porous composite ceramics with 90% and 70% mass contents of hydroxyapatite are promising materials for bone tissue regeneration.

Titanium Dioxide/Graphene Oxide Composite Coatings for 316 Stainless Steel Dental Implants.

Stainless steel has been used in orthopedics and orthodontic fields. However, it cannot be used for fabrication of dental implants due to its inertness, low biocompatibility and weak resistance to corrosion. A composite coating of titanium oxide /graphene oxide has been prepared for stainless steel to improve its biological properties. Stainless steel discs were polished, cleaned and pre-treated with a mixture of HNO3 and HF acid for 15 min. The composite coating composed of TiO2 produced by sol-gel technique and doped with 0.75 wt% graphene oxide. XRD, SEM-EDX and AFM were employed to characterize the composite coating. The anti-bacterial action of the composite coating was investigated against S. aureus and E. coli. The corrosion resistance of coated and noncoated samples was assessed in SBF using electrochemical technique. Cytotoxicity was assessed using osteoblast-like cells. The wettability was determined by contact angle, and bioactivity assessed by immersion in SBF. The results revealed that the composite coating was dense with few micro-cracks, and was not cytotoxic to osteoblast-like cells. The composite coating reduced bacterial colonies and the corrosion rate of the steel was improved. The wettability of the sample was increased with the composite coating and apatite formation appeared after 21 days.

Investigation on the Synthesis, Biomineralization, Mechanical Strength and Biocompatibility of Rankinite Bioceramics Derived from Eggshell and Rice Husk Waste for Biomedical Applications

AbstractSilicate bioceramics has an integrative advantage over metallic and polymeric biomaterials that have been widely employed for the reclamation of recreating the injured bone tissues. This advantage allows silicate bioceramics to replace damaged bone tissues in a natural way. The current study attempts the development of rankinite from eggshell and rice husk wastes. CaO and SiO2 extracted from the biowaste were combined in the stoichiometric ratio, resulted in the formation of highly crystalline single phasic rankinite upon calcination at 1300 °C. Further the formation of rankinite was confirmed with the analytical techniques such as XRD, FT‐IR, SEM and HRTEM respectively. In‐vitro bioactivity studies of rankinite publicized that the complete coverage of the surface with HAp layer was observed within 9 days of immersion in the SBF medium. The scaffolds when subjected to the compressive strength analysis after 9 days of immersion in SBF, rankinite showed the mechanical strength of about 179 MPa which falls under the human cortical bone level. The cytotoxicity results of rankinite showed high percentage cell viability at lower concentration (6.25 μg/mL) against MG63 cell lines. The results conferred that rankinite derived from biowaste showed excellent apatite nucleation and compatible mechanical strength for bone tissue engineering applications.

Enhanced in vitro immersion behavior and antibacterial activity of NiTi orthopedic biomaterial by HAp-Nb2O5 composite deposits

NiTi is a class of metallic biomaterials, benefit from superelastic behavior, high biocompatibility, and favorable mechanical properties close to that of bone. However, the Ni ion leaching, poor bioactivity, and antibacterial activity limit its clinical applications. In this study, HAp-Nb2O5 composite layers were PC electrodeposited from aqueous electrolytes containing different concentrations of the Nb2O5 particles, i.e., 0–1 g/L, to evaluate the influence of the applied surface engineering strategy on in vitro immersion behavior, Ni2+ ion leaching level, and antibacterial activity of the bare NiTi. Surface characteristics of the electrodeposited layers were analyzed using SEM, TEM, XPS, and AFM. The immersion behavior of the samples was comprehensively investigated through SBF and long-term PBS soaking. Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) infective reference bacteria were employed to address the antibacterial activity of the samples. The results illustrated that the included particles led to more compact and smoother layers. Unlike bare NiTi, composite layers stimulated apatite formation upon immersion in both SBF and PBS media. The concentration of the released Ni2+ ion from the composite layer, containing 0.50 g/L Nb2O5 was ≈ 60% less than that of bare NiTi within 30 days of immersion in the corrosive PBS solution. The Nb2O5-reinforced layers exhibited high anti-adhesive activity against both types of pathogenic bacteria. The hybrid metallic-ceramic system comprising HAp-Nb2O5-coated NiTi offers the prospect of a potential solution for clinical challenges facing the orthopedic application of NiTi.