Simulated Body Fluid Solution Research Articles

Enhancement of Bone Mineral Formation on Ti6Al4V Surface by PM-EDCLT Combined with Acid Etching

For Bone-anchored limb prostheses, osseointegration plays a significant role in the mechanically stable interface between bone and implants. Titanium alloy is the most usable alloy for hard tissue replacement. The drawbacks of the titanium implant are corrosion, leaching and poor osseointegration. In this research, powder mixed (hydroxyapatite) - electric discharge-assisted centreless turning (PM-EDCLT) (Impulse current- 5amp, duty factor- 57%, hydroxyapatite concentration 18g/l, and rpm-360) and acid etching (solution – HF: HNO3: H2O = 1:2:50) were used for the surface modification of screw-fit implants. Average surface roughness value maximum in PM-EDCLT machined surface (1.249µm) followed by PM-EDCLT machined + 5min. Acid etching (1.055µm), PM-EDCLT machined + 10min. Acid etching (0.9829µm), PM-EDCLT machined + 15min. acid etching (0.8223µm), bare surface with 10min. Acid etching (0.2866µm), 15min. acid etching (0.2714µm) and 5min. Acid etching (0.1896 µm). Investigations using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) proved that the deposited layer on the powder-mixed EDCLT machined sample was hydroxyapatite. After sinking samples in the Simulated Body Fluid (SBF) solution, it was concluded that the percentage of bone minerals like oxide, Ca, and P deposition increases after increasing the acid etching time on the PM-EDCLT machined surfaces. Little effect was found on the deposition of bone minerals on the surface of acid etching only by increasing the etching time. There is a clear trend of decreasing the contact angle with increasing the acid etching time on the PM-EDCLT surfaces.

Influence of adhesive systems containing different functional monomers on the longevity of bond strength at different dentin depths

This study evaluated the influence of adhesive systems containing different functional monomers on the longevity of bond strength (BS) to superficial (SD) and deep dentin (DD). Thirty molars were sectioned longitudinally, to obtain regions of SD (closest to the dentin-enamel junction) and DD (closest to the pulp chamber). Adhesive systems were applied (n = 10): Clearfil SE Bond (containing 10-MDP), FL-Bond II (containing 4-MET) and OptiBond Universal (containing GPDM). Microcylinders were made of resin composite (Filtek Z250) in SD and DD. After 24 h or 180 days of storage in Simulated Body Fluid (SBF) solution, BS tests were carried out. The fracture mode was evaluated by scores. ANOVA showed that there was no statistically significant difference between the adhesives in terms of BS (p = 0.5156). There was no significant difference between storage times for the three adhesive systems (p = 0.4703). There was a significant interaction between storage time and dentin depth (p = 0.0175), and in the time interval of 24 h, irrespective of the adhesive system, BS was significantly higher in SD than in DD (p < 0.05). In the time interval of 24 h, there was a significant association between the adhesive and the type of failure in SD (p = 0.0085) (Fisher's Exact test). Under these conditions, only OptiBond Universal showed cohesive failures in dentin (10 %) and mixed failures (15 %). After 180 days of storage, the percentages of early failures in deep dentin were 25.0 % (OptiBond Universal), 16.7 % (Clearfil SE Bond) and 0.0 % (FL-Bond II), with a significant difference between adhesives regarding early failures (p = 0.0410). The adhesive systems showed similar BS at different dentin depths over time, irrespective of the composition of functional monomers. FL Bond II was the only adhesive system that did not show early failures mode in DD within 180 days.

Development of a Novel Formulation of Bioactive Glass Based Calcium Phosphate Cement for Bone Grafting

AbstractParticulate bone grafting material can travel from the implantation site and diminish the magnitude of required bone formation response and hence its effectiveness. An easily prepared moldable graft that rapidly sets rigid in situ would alleviate this problem and in this study, such an injectable bone graft material is presented. By combining calcium phosphate (CP) salts with a bioactive glass (BG) mixed with a 2.5% Na2HPO4 solution a novel BG‐based calcium phosphate cement (CPC) is produced. Immersion in Tris buffer and simulated body fluid (SBF) solutions result in the rapid generation of octacalcium phosphate (OCP) and hydroxyapatite (HA) phases – a pre‐requisite for “bioactivity”. Cement‐conditioned media does not result in any cytotoxic potential with respect to MTT activity, DNA content, or alkaline phosphatase activity with an osteoblastic cell line. Application of the cement into standardized surgical defects in the minipig mandible results in short‐term, moderate irritation at 3 and 6 weeks and complete replacement of cement with new bone at 12 weeks.

Degradation of chitosan–gelatin and chitosan–gelatin–β-tricalcium phosphate scaffolds

Background: Fabrication of the composite scaffold was carried out by combining chitosan, gelatin, and β-tricalcium phosphate (βTCP) derived from limestone. The extraction of βTCP was based on the abundance of limestone containing calcium carbonate, which can be a source of βTCP synthesis. Purpose: This study evaluates the degradation of the combination of chitosan–gelatin (ChG) and chitosan–gelatin–βTCP (ChG-βTCP) composite scaffolds. Methods: The freeze-drying method was used to obtain the composite scaffold, which was a mixture of chitosan, gelatin, and βTCP. Degradation was measured by immersing the samples in a simulated body fluid solution at 37°C for 3, 7, 14, and 21 days. For statistical analysis, one-way analysis of variance (ANOVA) and post hoc Fisher’s least significant difference were performed. Results: The ChG scaffold shows better degradability than the ChG-βTCP scaffold. The ChG scaffold shows higher weight degradation than the ChG-βTCP scaffold up to 21 days. Conclusion: In conclusion, the scaffold containing βTCP has lower degradation than the ChG scaffold.

Corrosion resistance and ion exchange properties of montmorillonite film on AZ31 in SBF solution

Montmorillonite (MMT) film was prepared on the surface of alkali-heat treated Mg alloys by one-step hydrothermal method. The structure and composition of MMT film were characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The corrosion resistance of MMT film in simulated body fluid (SBF) was investigated using electrochemical tests and immersion experiments. The experimental results showed that with the extension of hydrothermal time, the corrosion resistance of film increased and then decreased. With the increase of MMT powder mass fraction in precursor solution, the corrosion resistance of films also increased and then weakened. The best performance of MMT films was obtained at hydrothermal time of 12h and MMT powder mass fraction of 2wt.%, with an impedance value of 9.77×106 Ω·cm2, which is an improvement of four orders of magnitude compared to substrate, and the efficiency of corrosion protection was up to 100%. The ion exchange properties, barrier effect and inertness characteristics of MMT provide excellent corrosion protection for magnesium substrates. This study provides a new coating strategy for the preparation of biodegradable magnesium alloys with excellent corrosion resistance and biocompatibility for use as biomedical materials.

Microstructure, wear resistance, corrosion behavior, and cytotoxicity of Mg-Zn-Ca amorphous coatings fabricated by laser surface melting

To address the issues of rapid degradation rate in biodegradable magnesium alloys, which seriously restricts their clinical application, this study employed laser surface melting (LSM) on Mg-Zn-Ca alloys. The impact of the LSM process on the microstructural characteristics of magnesium alloy was examined. Subsequently, an assessment was conducted to analyze the hardness, corrosion resistance, friction and wear properties, as well as cytotoxicity of amorphous coatings applied on magnesium alloy for potential use in biodegradable implants. When the laser scanning power was set at 500 W and scanning speed was adjusted to 90 mm/s, the LSM alloy exhibited good comprehensive of properties, with a microhardness of 540 HV and a friction coefficient of 0.2024. Electrochemical analysis conducted in simulated body fluid (SBF) solution revealed that the LSM sample demonstrated favorable resistance to corrosion, as evidenced by a corrosion potential of -1.3346 V, corrosion current density of 0.0199 mA/cm2, and corrosion rate of 0.455 mm/y. Both the cast and LSM alloys exhibited non-toxicity towards SaOS2 cells, with the LSM alloys displaying slightly superior biocompatibility than the as-cast alloys.

A NEW APPROACH TO CONTROL DIABETES BY CONVERTING EXCESS BLOOD SUGAR TO ENERGY OVER ELECTROCATALYTIC METALLIC ANODE

Diabetes Mellitus, or Diabetes in short, is a group of widespread endocrine diseases characterized by high blood sugar levels. This research paper attempts to find a solution to this high sugar problem, by taking the route of electrochemistry. It was attempted to demonstrate that the excess sugar (glucose) in the bloodstream of a diabetic patient can be lowered by electro-oxidizing the excess sugar in Simulated Body Fluid (SBF) and convert it into electrical energy. For this, a sugar level detection system was developed, using a linear regression model with a coefficient of determination (R2 value) of 0.974. At first, one of the most popular as well as costly electrocatalytic materials i.e., Platinum was used to electro-oxidize the excess sugar. Upon its success, some highly electrocatalytic but cheap electrode materials were developed, such as Nickel, Nickel with nanocarbon, Manganese dioxide (MnO2) and Manganese dioxide with nanocarbon (MnO2C). And they also successfully electro-oxidized the excess glucose in SBF solution, thereby reducing the sugar levels. Thus, a potentially novel route to deal with the epidemic problem of diabetes has been proposed through this research work.

On the way to increase osseointegration potential: Sequential SI-ATRP as promising tool for PEEK-based implant nano-engineering

In the search of the ideal bone implant material, surface initiated atom transfer radical polymerization (SI-ATRP) techniques were successfully employed to modify the polyetheretherketone (PEEK) surface with complex architecture nanolayers featuring hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) or poly(2-hydroxyethyl methacrylate) (PHEMA) branches. As a result, polymer layers with height up to over 300 nm were synthesized to decrease the water contact angle from 92.8° to 23.0°. In-depth analysis of layer topography, structure and elemental composition realized with atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), time-of-flight secondary ions mass spectroscopy (TOF-SIMS) and X-ray photon spectroscopy (XPS) confirmed successful surface modification. Additionally, to demonstrate the applicability of proposed PEEK functionalization, the biomineralization assay in simulated body fluid (SBF) solution was conducted. The high density of hydroxyl and amine groups in branched polymer brushes structure enhanced the rate of hydroxyapatites (HAp) formation substantially. Compared to untreated PEEK, modification with polymer brushes resulted in the creation of cauliflower-like structures with high specific surface area and Ca/P ratio equal to 1.83–1.87 for PEEK grafted with brushes composed of PHEMA backbone segment and PDMAEMA or PHEMA as block polymer branches (PEEK-g-PHEMA-g-PDMAEMA or PEEK-g-PHEMA-g-PHEMA) after 2 weeks. Finally, the process of the hydroxyapatite formation and increase of the layer thickness in a range of 14 days to 6 weeks of immersion in SBF was thoroughly visualized by scanning electron microscopy (SEM).

Effects of MgO nanoparticle addition on the mechanical properties, degradation properties, antibacterial properties and in vitro and in vivo biological properties of 3D-printed Zn scaffolds

Bone tissue engineering is the main method for repairing large segment bone defects. In this study, a layer of bioactive MgO nanoparticles was wrapped on the surface of spherical Zn powders, which allowed the MgO nanoparticles to be incorporated into 3D-printed Zn matrix and improved the biodegradation and biocompatibility of the Zn matrix. The results showed that porous pure Zn scaffolds and Zn/MgO scaffolds with skeletal-gyroid (G) model structure were successfully prepared by selective laser melting (SLM). The average porosity of two porous scaffolds was 59.3 and 60.0%, respectively. The pores were uniformly distributed with an average pore size of 558.6–569.3 μm. MgO nanoparticles regulated the corrosion rate of scaffolds, resulting in a more uniform corrosion degradation behavior of the Zn/MgO scaffolds in simulated body fluid solution. The degradation ratio of Zn/MgO composite scaffolds in vivo was increased compared to pure Zn scaffolds, reaching 15.6% at 12 weeks. The yield strength (10.8 ± 2.4 MPa) of the Zn/MgO composite scaffold was comparable to that of cancellous bone, and the antimicrobial rate were higher than 99%. The Zn/MgO composite scaffolds could better guide bone tissue regeneration in rat cranial bone repair experiments (completely filling the scaffolds at 12 weeks). Therefore, porous Zn/MgO scaffolds with G-model structure prepared with SLM are a promising biodegradable bone tissue engineering scaffold.

Experimental and finite element simulation studies of the bio-tribological behavior of L-PBF Ti-6Al-4V alloys with various surface roughness

Recently, 3D-printed Ti-6Al-4 V alloys have been gradually used for medical implants, where surface quality plays a crucial role in bio-tribological resistance. In this study, we designed three Ti-6Al-4 V samples through mechanical grinding, polishing, and sandblasting to explore the effect of surface roughness on the bio-tribological behavior against the Si3N4 counter-ball in a simulated body fluid (SBF) solution. Results indicate an increasing trend in the bio-tribological properties with decreasing surface roughness, with the polished sample exhibiting the lowest wear rate (2.73 × 10−3 mm3/N·m) and superior bio-tribological resistance. Finite element simulation reveals that asperities on the rougher surface sample lead to stress concentration, forming larger asperity fragments, enhancing mechanical interlocking and thus intensifying wear. Additionally, with increasing surface roughness, the wear mechanism of the as-printed Ti-6Al-4 V alloy shifts from abrasive and adhesive wear to a combination of abrasive, adhesive, and oxidative wear. This study provides valuable insights into the effect of surface roughness on the bio-tribological properties of as-printed Ti-6Al-4 V alloys, offering guidance for regulating surface quality in biomedical implants.

Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films.

The structure, composition and corrosion properties of thin films synthesized using the Pulsed Laser Deposition (PLD) technique starting from a three high entropy alloy (HEA) AlCoCrFeNix produced by vacuum arc remelting (VAR) method were investigated. The depositions were performed at room temperature on Si and mirror-like polished Ti substrates either under residual vacuum (low 10-7 mbar, films denoted HEA2, HEA6, and HEA10, which were grown from targets with Ni concentration molar ratio, x, equal to 0.4, 1.2, and 2.0, respectively) or under N2 (10-4 mbar, films denoted HEN2, HEN6, and HEN10 for the same Ni concentration molar ratios). The deposited films' structures, investigated using Grazing Incidence X-ray Diffraction, showed the presence of face-centered cubic and body-centered cubic phases, while their surface morphology, investigated using scanning electron microscopy, exhibited a smooth surface with micrometer size droplets. The mass density and thickness were obtained from simulations of acquired X-ray reflectivity curves. The films' elemental composition, estimated using the energy dispersion X-ray spectroscopy, was quite close to that of the targets used. X-ray Photoelectron Spectroscopy investigation showed that films deposited under a N2 atmosphere contained several percentages of N atoms in metallic nitride compounds. The electrochemical behavior of films under simulated body fluid (SBF) conditions was investigated by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy measurements. The measured OCP values increased over time, implying that a passive layer was formed on the surface of the films. It was observed that all films started to passivate in SBF solution, with the HEN6 film exhibiting the highest increase. The highest repassivation potential was exhibited by the same film, implying that it had the highest stability range of all analyzed films. Impedance measurements indicated high corrosion resistance values for HEA2, HEA6, and HEN6 samples. Much lower resistances were found for HEN10 and HEN2. Overall, HEN6 films exhibited the best corrosion behavior among the investigated films. It was noticed that for 24 h of immersion in SBF solution, this film was also a physical barrier to the corrosion process, not only a chemical one.

Injectable macroporous naturally-derived apatite bone cement as a potential trabecular bone substitute.

In this study, we have formulated a novel apatite bone cements derived from natural sources (i.e. eggshell and fishbone) with improved qualities that is, porosity, resorbability, biological activity, and so forth. The naturally-derived apatite bone cement (i.e. FBDEAp) was prepared by mixing hydroxyapatite (synthesized from fishbone) and tricalcium phosphate (synthesized from eggshell) as a solid phase with a liquid phase (a dilute acidic blend of cement binding accelerator and biopolymers like gelatin and chitosan) with polysorbate (as liquid porogen) to get a desired bone cement paste. The prepared cement paste sets within the clinically acceptable setting time (≤20 min), easily injectable (>85%) through hands and exhibits physiological pH stability (7.3-7.4). The pure apatite phased bone cement was confirmed by x-ray diffraction and Fourier transform infrared spectroscopy analyses. The FBDEAp bone cement possesses acceptable compressive strength (i.e. 5-7 MPa) within trabecular bone range and is resorbable up to 28% in simulated body fluid solution within 12 weeks of incubation at physiological conditions. The FBDEAp is macroporous in nature (average pore size ~50-400 μm) with interconnected pores verified by SEM and micro-CT analyses. The FBDEAp showed significantly increased MG63 cell viability (>125% after 72 h), cell adhesion, proliferation, and key osteogenic genes expression levels (up to 5-13 folds) compared to the synthetically derived, synthetic and eggshell derived as well as synthetic and fishbone derived bone cements. Thus, we strongly believe that our prepared FBDEAp bone cement can be used as potential trabecular bone substitute in orthopedics.

PMMA bone cement with L-arginine/nano fish bone nanocomplex for apatite formation.

Bone cement is one of the materials used in orthopaedics that serves various functions, such as binding bone implants, replacing damaged bones and filling spaces within bones. Various materials have been used to synthesize bone cement, and one promising material for further research is fish bone waste-based bone cement. This study investigates the potential of fish bone waste-based bone cement by incorporating nano fish bone (NFB) and L-arginine (L-Arg) protein into polymethyl methacrylate (PMMA) to examine apatite growth. NFB derived from the Salmo salar fish positively influences osteoblast cell proliferation and differentiation, while L-Arg enhances biocompatibility and antibiotic properties. The NFB/L-Arg combination holds promise in accelerating new bone formation and cell growth, both of which are crucial for fracture healing and bone remodelling. Tensile strength tests reveal the superior performance of BC-PMMA-1-NFB/L-Arg (36.11 MPa) compared with commercial PMMA (32 MPa). Immersion tests with simulated body fluid (SBF) solution for 7 days reveal accelerated apatite layer formation, emphasizing the potential benefits of NFB/L-Arg in bone cement applications.

Maximizing Corrosion Resistance of HA+Ce Coated Mg Implants Using Random Forest and Whale Optimization Algorithm

In this paper, a hybrid three-stage methodology based on in vitro experiments, simulations, and metaheuristic optimization is presented to enhance the corrosion resistance of hydroxyapatite (HA)-coated magnesium implants in biomedical applications. In the first stage, we add cerium (Ce) to HA and present a new coating (named HA+Ce) to improve the resistance of the coating to corrosion. Then, various HA+Ce compounds with different factors (e.g., concentration, pH, immersion time, and temperature) are generated and their propensity for corrosion is examined in a physiological environment using EIS and DC polarization tests in a simulated body fluid solution. Eventually, a comprehensive dataset comprising 1024 HA+Ce coating samples is collected. In the second stage, machine learning using random forest (RF) is used to learn the relation between the input factors of the coating and its corrosion resistance. In the third stage, a metaheuristic algorithm based on the whale optimization algorithm (WOA) is utilized to find the best HA+Ce compound with the maximum corrosion resistance, while the objective function of WOA for a new unseen coating solution is estimated using the trained RF model. Finally, the morphology and composition of the best coating solution are inspected using FE-SEM. According to the obtained results, the HA+Ce coating with an immersion time of 60 min, concentrations of 0.9 for Ce and 1.2 for HA, pH of 4.1 for solution, and temperature of 70 °C demonstrated the highest level of corrosion resistance among all experiments and simulations. The final optimized HA+Ce coating solution has obtained a corrosion resistance of 14,050 Ω·cm2, which resulted in a gain of 14.9% compared to the HA-coated Mg implants.

Surface modification of Ti6Al4V alloy: A case study on anti‐Streptococcus mutans

AbstractThis study aims to improve the antibacterial effectiveness against Streptococcus mutans (S. mutans) of Ti6Al4V alloy by employing functional Ag coating on the alloy's surface. In this study, Ag coating was prepared on Ti6Al4V surface via RF magnetron sputtering, then investigated characteristics and anti‐S. mutans properties of the modified surface's alloy before and after immersing in simulated body fluid (SBF) solution for one month. Data showed that the two coatings inhibited the development of S. mutans colony‐forming units (CFU) at an incubation time until seven days. This study provides a research foundation for further development of surface modification of Ti6Al4V alloy for dental implants to meet the demand of reducing peri‐implant diseases caused by bacteria.

Towards bone regeneration: Understanding the nucleating ability of proline-rich peptides in biomineralisation

Obtaining rapid mineralisation is a challenge in current bone graft materials, which has been attributed to the difficulty of guiding the biological processes towards osteogenesis. Amelogenin, a key protein in enamel formation, inspired the design of two intrinsically disordered peptides (P2 and P6) that enhance in vivo bone formation, but the process is not fully understood. In this study, we have elucidated the mechanism by which these peptides induce improved mineralisation. Our molecular dynamics analysis demonstrated that in an aqueous environment, P2 and P6 fold to interact with the surrounding Ca2+, PO43− and OH− ions, which can lead to apatite nucleation. Although P2 has a less stable backbone, it folds to a stable structure that allows for the nucleation of larger calcium phosphate aggregates than P6. These results were validated experimentally in a concentrated simulated body fluid solution, where the peptide solutions accelerated the mineralisation process compared to the control and yielded mineral structures mimicking the amorphous calcium phosphate crystals that can be found in lamella bone. A pH drop for the peptide groups suggests depletion of calcium and phosphate, a prerequisite for intrinsic osteoinduction, while S/TEM and SEM suggested that the peptide regulated the mineral nucleation into lamella flakes. Evidently, the peptides accelerate and guide mineral formation, elucidating the mechanism for how these peptides can improve the efficacy of P2 or P6 containing devices for bone regeneration. The work also demonstrates how experimental mineralisation study coupled with molecular dynamics is a valid method for understanding and predicting in vivo performance prior to animal trials.

45S5/PEEK Coatings by Cold Gas Spray with In Vitro Bioactivity, Degradation, and Cellular Proliferation

This study evaluated the biological response of cold-sprayed coatings composed of bioactive glass 45S5 and polyetheretherketone (PEEK). The functional coatings were produced by cold gas spray (CGS) technology, a technique that allows the deposition of powders at significantly low temperatures, avoiding heat damage to polymeric surfaces. By CGS, blends with different ratios of bioactive glass and PEEK powders have been deposited onto PEEK substrates to improve the response of the bio-inert polymer. The bioactivity of the coatings when immersed in a simulated body fluid solution was evaluated by observation with scanning electron microscopy (SEM) and x-ray diffraction (XRD). Results verify that bioactive glass particles in the composite coatings enhance their bioactivity. A degradation test was performed with Tris–HCl solution. From the results obtained by inductively coupled plasma optical emission spectroscopy (ICP-OES) and the weight loss of the samples, it was noticed that the degradation was directly related to the amount of glass in the coatings. Finally, the ability of bone-forming cells to adhere and proliferate on the coatings was evaluated. These experiments showed that the presence of glass particles does not cause a significant increase in cell proliferation. Combining a bioactive material with PEEK leads to forming a final component that provides suitable bioactivity to the final implant.

Tuning biodegradability, bone-bonding capacity, and wear resistance of zinc-30% magnesium intermetallic alloy for use in load-bearing bone applications

This work aimed to improve the rapid biodegradation, poor wear resistance properties, and lack of bioactivity of metallic biomaterials to be used in orthopedic applications. In this context, zinc–magnesium (Zn–Mg) alloy with successive contents of calcium silicate (CaSiO3) and silicon nitride (Si3N4) was prepared using powder metallurgy technique. After sintering, their phase composition and microstructure were investigated using the X-ray diffraction technique and scanning electron microscopy (SEM), respectively. Furthermore, their degradation behavior and ability to form hydroxyapatite (HA) layer on the sample surface after immersion in simulated body fluid (SBF) were monitored using weight loss measurements, inductively coupled plasma-atomic emission spectroscopy, and SEM. Moreover, their tribo-mechanical properties were measured. The results obtained showed that the successive contents of CaSiO3 were responsible for improving the bioactivity behavior as indicated by a good formation of the HA layer on the samples’ surface. Additionally, ceramic materials were responsible for a continuous decrease in the released ions in the SBF solution as indicated by the ICP results. The tribology properties were significantly improved even after exposure to different loads. Based on the above results, the prepared nanocomposites are promising for use in orthopedic applications.

Fabrication and characterization of 3D-printed composite scaffolds of coral-derived hydroxyapatite nanoparticles/polycaprolactone/gelatin carrying doxorubicin for bone tissue engineering

In this study, nanocomposite scaffolds of hydroxyapatite (HA)/polycaprolactone (PCL)/gelatin (Gel) with varying amounts of HA (42–52 wt. %), PCL (42–52 wt. %), and Gel (6 wt. %) were 3D printed. Subsequently, a scaffold with optimal mechanical properties was utilized as a carrier for doxorubicin (DOX) in the treatment of bone cancer. For this purpose, HA nanoparticles were first synthesized by the hydrothermal conversion of Acropora coral and characterized by using different techniques. Also, a compression test was performed to investigate the mechanical properties of the fabricated scaffolds. The mineralization of the optimal scaffold was determined by immersing it in simulated body fluid (SBF) solution for 28 days, and the biocompatibility was investigated by seeding MG-63 osteoblast-like cells on it after 1–7 days. The obtained results showed that the average size of the synthesized HA particles was about 80 nm. The compressive modulus and strength of the scaffold with 47 wt. % HA was reported to be 0.29 GPa and 9.9 MPa, respectively, which was in the range of trabecular bones. In addition, the scaffold surface was entirely coated with an apatite layer after 28 days of soaking in SBF. Also, the efficiency and loading percentage of DOX were obtained as 30.8 and 1.6%, respectively. The drug release behavior was stable for 14 days. Cytotoxicity and adhesion evaluations showed that the fabricated scaffold had no negative effects on the viability of MG-63 cells and led to their proliferation during the investigated period. From these results, it can be concluded that the HA/PCL/Gel scaffold prepared in this study, in addition to its drug release capability, has good bioactivity, mechanical properties, and biocompatibility, and can be considered a suitable option for bone tumor treatment.Graphical

A brief study of electrical and biological properties of BNT6BT/ZnO-HA Composite

The discovery of the piezoelectric properties of natural bone and their influence on bone growth within scaffolds has spurred researchers to investigate a range of bio-piezoelectric composite materials. By exploring these materials, researchers aim to better understand how piezoelectricity can be harnessed to promote bone growth and tissue regeneration, potentially leading to new breakthroughs in the field of regenerative medicine. In this study, the piezoelectric material, Bi0.5Na0.5TiO3-0.6BaTiO3/nano ZnO (BNT6BT/ZnO) and the biological hydroxyapatite (HA) were separately synthesized using the sol-gel method. The composite samples consisting of BNT6BT/ZnO and HA were fabricated using isostatic cold pressing. The composition and phase structure were studied using the X-ray diffraction (XRD) analysis, and the scanning electron microscopy (SEM) was used to study the microstructure and morphology. The presence of different phases and the distribution of elements were examined using EDAX elemental analysis and its corresponding maps. Among the composite samples the one containing 10 wt% HA (BNT6BT/ZnO-10HA) possessed the best dielectric properties. The Vickers hardness measurements showed that the addition of HA to the piezoelectric phase BNT6BT/ZnO results in higher hardness values, which expects to increase the fracture toughness of HA due to the higher elastic modulus to hardness ratio (E/H) of composite samples compared to pure HA. The in vitro bioactivity of the samples was tested in simulated body fluid (SBF) solution and the cell culture analysis was performed to examine the biocompatibility of the samples. Accordingly, apatite was deposited on the surface of the samples and all of the composite samples were bioactive. Furthermore, the BNT6BT/ZnO-10HA sample containing the largest amount of deposit showed the highest optical density (OD) in the MTT test.