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Central nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate functional CNS tissue after injury. Hydrogels can mimic the neural extracellular matrix by providing a suitable 3D structure and mechanical properties and have shown great promise in CNS tissue regeneration. Here we present successful synthesis of a thermosensitive hyaluronic acid-RADA 16 (Puramatrix™) peptide interpenetrating network (IPN) that can be applied in situ by injection.Thermosensitive hyaluronic acid (HA) was first synthesized by combining HA with poly(N-isopropylacrylamide). Then, the Puramatrix™ self-assembled peptide was combined with the thermosensitive HA to produce a series of injectable thermoresponsive IPNs. The HA-Puramatrix™ IPNs formed hydrogels successfully at physiological temperature. Characterization by SEM, rheological measurements, enzymatic degradation and swelling tests was performed to select the IPN optimized for neurologic use. SEM images of the optimized dry IPNs demonstrated an aligned porous structure, and the rheological measurements showed that the hydrogels were elastic, with an elastic modulus of approximately 500 Pa, similar to that of brain tissue. An evaluation of the cell–material interactions also showed that the IPN had biological characteristics required for tissue engineering, strongly suggesting that the IPN hydrogel possessed properties beneficial for regeneration of brain tissue.

In this research, bioglass nanoparticles were synthesized via sol-gel method and a polycaprolactone-chitosan-bioglass nanocomposite coating was formed on SS316L substrate using electrophoretic deposition method. Then, the effects of voltage and deposition time on morphology, thickness, roughness, and wettability of final coating were investigated. Finally, biocompatibility and toxicity of the coating were evaluated. The results showed that increase of both time and voltage enhanced the thickness, roughness, and wettability of coating. Also, increase of deposition time increased the agglomeration. Therefore, it can be concluded that voltage of 20 V and time of 10 min are suitable for the formation of a uniform agglomerate-free coating. The presence of bioglass nanoparticles also led to the increase of roughness and improvement of polycaprolactone hydrophobicity. The results also showed higher bioactivity in polycaprolactone-chitosan-1% bioglass nanocomposite coating sample. This sample had a roughness ( Ra) of 1.048 ± 0.037 μm and thickness of 2.54 ± 0.14 μm. In summary, the results indicated that coating of polycaprolactone-chitosan-bioglass nanocomposite on SS316L substrate could be a suitable surface treatment to increase its in vivo bioactivity and biocompatibility.

Detoxification of aflatoxin M1 from solution and milk using layered double hydroxides was investigated. The Aluminum-Magnesium layered double hydroxide (Al-Mg LDH) and Iron-Magnesium layered double hydroxide (Fe-Mg LDH) were selected in their calcined and non-calcined forms to evaluate the effect of the calcination on detoxification. These materials were produced using the co-precipitation method. Preliminary adsorption tests confirmed use of Al-Mg LDH as the selected adsorbent. Characteristics of the adopted adsorbent were studied and confirmed by XRD, FTIR, SEM, and BET methods. Effects of the initial content of aflatoxin, amount of the adsorbents and detoxification time were investigated. Influence of the adsorbents on the nutritional aspects of milk were also studied. The study showed that while the non-calcined forms of LDH were not able to adsorb aflatoxin M1 more than 23%, the calcined form of Al-Mg LDH exhibited 100% adsorption in the solutions and about 70-100% in the contaminated milk samples. The reason is pointed to the fact that calcination of Al-Mg LDH considerably increased the surface area, the total pore volume, and the pore size of the material. Multivariate regression analysis and calculation of the Pearson correlation factor showed that the remained aflatoxin at each time was more strongly correlated with the initial amount of aflatoxin and the elapsed time and less strongly with the amount of the adsorbent. It was found that the adsorption isotherms fitted to the Freundlich equation with a high adsorption capacity of 555.5 mg g-1. PRACTICAL APPLICATION: This study is focused on examining ability of layered double hydroxides (LDH) for adsorbing AFM1 . LDHs are promising layered materials due to some of their interesting characteristics, such as ease of synthesis and uniqueness of structure. In practice, results of this study can be used for detoxification of aflatoxin, especially in milk, at high efficiency in shorter time durations.

This research investigates the oxidation behavior of nanocrystalline/amorphous Si3N4 compounds in atmospheres with different oxygen pressures. High purity nanocrystalline/amorphous Si3N4 and MgAl2O4 mixtures were used to investigate oxidation behavior of Si3N4. Si3N4-xMgAl2O4 (0

Microstructure and microtexture of a dual-phase (DP) steel was investigated using the electron backscattered diffraction (EBSD) technique. A DP600 steel was produced by 60% cold-rolling a low carbon steel with an initial ferrite pearlite microstructure followed by intercritical annealing at 720°C for 1 h. Kernel average misorientation map of the DP600 steel showed that the density of geometrically necessary dislocations as well as the local misorientation is higher in the vicinity of ferrite–martensite interfaces compared to the middle of the ferrite grains. Microtexture analysis of the cold-rolled steel by EBSD revealed that a strong α fiber and weaker γ fiber texture forms after cold-rolling. After intercritical annealing, the intensity of the α fiber texture is significantly reduced, whereas that of the more desirable γ fiber texture is slightly increased. The maximum texture intensity in the DP600 steel was observed for (112)[110] component in the α fiber, and (111)[123] and (111)[112] components in the γ fiber.

Local delivery of antibiotics utilising bone cement is a well-known approach for controlling postoperative infections related to implant. 1, 5 and 10 wt.% of clindamycin (Cli) was embedded into polymethylmethacrylate (PMMA)–based bone cement for inhibiting postsurgical infection. Clindamycin antibiotic drug was homogeneously embedded into the matrix of PMMA-based cement. The results revealed that the fabricated PMMA-based cement loaded with Cli presented a high compressive strength (~120 MPa). The PMMA-based cement loaded with low Cli presented better cytocompatibility compared with its counterpart loaded with high Cli owing to the better cell attachment on the surface of the cement with a lower release of Cli. The embedding of Cli into the cement improved its antibacterial performance, as implied by the considerably improved inhibition zone with amplifying Cli concentration. Taken together, PMMA-based cement loaded with 1–5 wt% Cli might be a promising antimicrobial bone cement to be employed in orthopaedic surgeries.

Hemostatic adhesive hydrogels as sealants for surgical operations are one of the focus of the researches in the field of injectable materials. Herein, we evaluated the potential application of a mechanically robust nanocomposite hydrogel with significant adhesion strength and shorter blood clotting time. This hydrogel was composed of thiolated gelatin (Gel-SH) and gelatin methacrylate (GelMA) as the main matrix to support cell viability and proliferation, while polydopamine functionalized Laponite® (PD-LAP) were introduced to the structure to improve the mechanical properties, adhesion strength, and blood clotting. This hydrogel formed via Michael reaction between Gel-SH and GelMA, and covalent interaction between PD-LAP and hydrogel. Results revealed that presence of PD-LAP significantly controlled the swelling ratio, biodegradability, and mechanical properties of nanocomposite hydrogels. Tensile and compressive strength of nanocomposite hydrogels were measured in the range of 22–84 kPa and 54–153 kPa, respectively. Furthermore, nanocomposite hydrogels revealed excellent recovery ability, strong tissue adhesiveness and significantly less blood clotting time than Gel-SH/GelMA hydrogel (2.25 min). In the culture with L929 fibroblasts cells, viability more than 97% and high proliferation after 5 days of culture was estimated. The simplicity, low-cost, tunable mechanical properties, short blood clotting time, and cytocompatibility of the hydrogels composed of Gel-SH, GelMA, and PD-LAP highlight its potential as hemostat sealants.

In recent years, the main challenge for producers and consumers of doloma-containing refractories has been to increase the performance of this kind of refractories. In this study, the addition effect of magnesium-aluminate spinel nano-particles (MgAl2O4) on various properties of doloma-containing refractories such as bulk density, apparent porosity, hydration resistance and cold compressive strength have been evaluated. From 0 to 8 wt % magnesium-aluminate spinel nano-particles added to the specimens. The prepared cylindrical specimens (50*50mm2) were putted in a dryer (at 110 °C for 24 h) and then placed in an electrical furnace (at 1650 °C for 3 h). Ceramic phase's identification and microstructural evaluation of the fired specimens were donned by helping X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM/EDX) techniques, respectively. Results showed that the bulk density increased up to 8 wt % nano-spinel. Also, the cold compressive strength values of the samples increased up to 6 wt % nano-spinel whereas the apparent porosity values were reduced. However, for the higher additive value (8 wt % nano-spinel), this trends is reversed and the cold compressive strength was decreased and apparent porosity was increased. The reason for this variation can be attributed to the formation of some micro-cracks in the specimen's matrix. As well as, due to the formation of dense microstructures by utilization of magnesium-aluminate spinel nano-particles the resistance to hydration of the specimens has increased significantly.

Detoxification of aflatoxin M

The void formation and plastic deformation micromechanisms of a cold-rolled DP600 steel during tensile loading were studied by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The SEM observations revealed that the main void nucleation mechanism in the DP600 steel is decohesion at the ferrite–martensite interfaces. The voids were mostly observed between the closely spaced martensite islands situated at the boundaries of relatively finer ferrite grains. The EBSD results indicated a strain gradient developed from the ferrite–martensite and ferrite–ferrite interfaces into the interior of ferrite grains during the tensile deformation, which led to a stress concentration at these interfaces. Moreover, it was demonstrated that local misorientation inside the finer ferrite grains surrounded by martensite islands was higher than that for the coarser ferrite grains, which made the former more prone to void initiation.

Today, consumers of refractory products have paid special attention to the use of dolomite-based products (bricks and castables). The reason of this attention can be attributed to the outstanding properties of dolomite-based products such as high refractoriness (more than 2000 °C ), the possibility of purified steel melt, high hot strength resistance, good resistance to corrosion in alkali environment and, most importantly, the low price of these types of refractories. But the problem that partly leads to a limitation of the use of these types of refractory products is their low resistance to hydration. In this study, the impact of magnesium-aluminate spinel nano-particles (MgAl 2 O 4 ) on the microstructure and resistance to hydration of fired dolomite refractory specimens has been investigated. It was showed that spinel nano-particles containing dolomite refractories effectively prevents the hydration and create a dens microstructure compared to dolomite refractory specimen without nano-sized spinel added. The reasons of this modification and improvement are related to the reducing of porosities, voids and grain-boundaries due to the generation of some phases with a low melting point such as CaO.Al 2 O 3 (CA) and3CaO.Al 2 O 3 (C 3 A) in the specimen's matrix with the addition of spinel nano-particles.

The capacity to simulate the construction of natural extracellular matrix is an effective approach to guided bone regeneration (GBR). Here, novel nanocomposite fibrous membranes of silk fibroin (SF)-Laponite® (LAP) were developed through electrospinning approach. The membranes were considered according to the physical and mechanical characteristics, degradation rate, in vitro bioactivity evaluation and biological properties. Results showed that the optimized nanocomposite fibrous membrane with meaningfully enhanced tensile strength, toughness and elastic modules was obtained via incorporation of 5 wt% LAP nanoplates into SF membrane. LAP nanoplates incorporation in the SF membrane promoted its hydrophilicity, swelling ratio, and degradation rate, while induced apatite mineralization in simulated body fluid. Moreover, nanocomposite fibrous membranes revealed meaningfully superior cellular responses compared to SF membrane. Consequently, nanocomposite SF-LAP fibrous membranes anticipated to being appealing for GBR applications.

In this study, spark plasma sintering (SPS) was used to prepare a TiB2-20 vol.% SiC composite with a relative density of above 99%. XRD and FESEM investigations indicated no reactions having taken place between the additive (SiC) and the matrix (TiB2) during the sintering process. The study of consolidation temperature (1700–2000 °C ) and holding time (3–10 min) effects on the sintering behavior and mechanical properties (including, micro-hardness, flexural strength, and indentation fracture toughness) revealed the significance of these effects on the densification and mechanical properties of the composite. The TiB2-20 vol.% SiC composite sintered at 1900 °C exhibited maximum values of micro-hardness (24.9 GPa), flexural strength (374 MPa), and fracture toughness (4.5 MPa m1/2). Finally, crack deflection around SiC particles and crack branching were identified as the main toughening mechanisms involved.

In recent decades, porous silica-based bioceramic scaffolds have received great attention for treatment of bone defects. One of the main drawbacks of these scaffolds is their inherent brittle nature and high degradation rate. Recently, using bioactive and biodegradable polymer coatings on the surface of scaffolds improves their mechanical properties and the ability to control their degradation rate. In this work, highly porous diopside/baghdadite composite scaffolds with and without surface modification were prepared by space holder method. Compressive strength, compressive modules, porosity and the pore size of the different scaffolds with different diopside contents were in the range of 0.28–1.33 MPa, 15.35–155 MPa, 64–78%, and 300–500 μm, respectively. The results showed that applying a PCLF cross-linked polymer coating on the scaffolds improved their compressive strength and modulus from 1.09 ± 0.1 and 139.3 ± 1.1 to 1.63 ± 0.2 and 189.1 ± 1 MPa, respectively. A negligible reduction in porosity and pore size was observed.

Progress in sustainable manufacturing is a crucial element to minimise negative environmental impacts. The conventional fusion weld process used to join aluminium alloys resulted in coarse grain structure, inevitable defects, and severe joint softening. Friction stir processing (FSP) has the potential to modify the microstructure of materials in joint structure and improve the mechanical properties. In this investigation, the effect of friction stir post–processing was evaluated to study the microstructural characteristics and mechanical properties of GTAW (gas tungsten arc welding) welds in the aluminium 5052 alloy. During FSP, the grains’ dendritic microstructure was destroyed, and the dynamic recrystallisation resulted in a very fine and equiaxed grains structure in the fusion zone. The hardness of the friction-stir-processed welds significantly improved because of microstructure grain refinement. The processed joint demonstrated higher ultimate tensile and yield strength (~275 MPa and 221 MPa, respectively) and superior elongation (31.1%) compared to the unprocessed weld, at the same time, the mechanical strength (yield and ultimate tensile) is similar to that of the base metal.

In tissue engineering, three-dimensional (3D) printing is an emerging approach to producing functioning tissue constructs to repair wounds and repair or replace sick tissue/organs. It allows for precise control of materials and other components in the tissue constructs in an automated way, potentially permitting great throughput production. An ink made using one or multiple biomaterials can be 3D printed into tissue constructs by the printing process; though promising in tissue engineering, the printed constructs have also been reported to have the ability to lead to the emergence of unforeseen illnesses and failure due to biomaterial-related infections. Numerous approaches and/or strategies have been developed to combat biomaterial-related infections, and among them, natural biomaterials, surface treatment of biomaterials, and incorporating inorganic agents have been widely employed for the construct fabrication by 3D printing. Despite various attempts to synthesize and/or optimize the inks for 3D printing, the incidence of infection in the implanted tissue constructs remains one of the most significant issues. For the first time, here we present an overview of inks with antibacterial properties for 3D printing, focusing on the principles and strategies to accomplish biomaterials with anti-infective properties, and the synthesis of metallic ion-containing ink, chitosan-containing inks, and other antibacterial inks. Related discussions regarding the mechanics of biofilm formation and antibacterial performance are also presented, along with future perspectives of the importance of developing printable inks.

In this study, various composites of bioglass/gelatin/polycaprolactone (BG/GE/PCL) were produced and coated on the surface of 316L stainless steel (SS) to improve its bioactivity. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were utilized to characterize the specimens. The results showed that bioglass particles were distributed uniformly in the coating. By increasing the wt.% of bioglass in the nanocomposite coatings, the surface roughness and adhesion strength increased. The corrosion behavior of GE/PCL (PCL-10 wt.% gelatin coated on 316L SS) and 3BG/GE/PCL (GE/PCL including 3 wt.% bioglass coated on 316L SS) samples were studied in PBS solution. The results demonstrated that 3BG/GE/PCL sample improved the corrosion resistance drastically compared to the GE/PCL specimen. In vitro bioactivity of samples was examined after soaking the specimens for 7, 14 and 28 days in simulated body fluid (SBF). The results showed a significant apatite formation on the surface of 3BG/GE/PCL samples. The cell viability evaluation was performed using 3- (4, 5-dimethylthiazol-2-yl)-2,5 diphenyltetrazoliumbromide (MTT) tests which confirmed the enhanced cell viability on the surface of 3BG/GE/PCL samples. The in vivo behavior of specimens illustrated no toxicity and inflammatory response and was in a good agreement with the results obtained from the in vitro test.

Three-dimensional (3D) bioprinting is an appealing and revolutionary manufacturing approach for the accurate placement of biologics, such as living cells and extracellular matrix (ECM) components, in the form of a 3D hierarchical structure to fabricate synthetic multicellular tissues. Many synthetic and natural polymers are applied as cell printing bioinks. One of them, alginate (Alg), is an inexpensive biomaterial that is among the most examined hydrogel materials intended for vascular, cartilage, and bone tissue printing. It has also been studied pertaining to the liver, kidney, and skin, due to its excellent cell response and flexible gelation preparation through divalent ions including calcium. Nevertheless, Alg hydrogels possess certain negative aspects, including weak mechanical characteristics, poor printability, poor structural stability, and poor cell attachment, which may restrict its usage along with the 3D printing approach to prepare artificial tissue. In this review paper, we prepare the accessible materials to be able to encourage and boost new Alg-based bioink formulations with superior characteristics for upcoming purposes in drug delivery systems. Moreover, the major outcomes are discussed, and the outstanding concerns regarding this area and the scope for upcoming examination are outlined.

Polymer&ndash, ceramic composite coatings on magnesium-based alloys have attracted lots of attention in recent years, to control the speed of degradability and to enhance bioactivity and biocompatibility. In this study, to decrease the corrosion rate in a simulated body fluid (SBF) solution for long periods, to control degradability, and to enhance bioactivity, polycaprolactone&ndash, chitosan composite coatings with different percentages of baghdadite (0 wt.%, 3 wt.%, and 5 wt.%) were applied to an anodized AZ91 alloy. According to the results of the immersion test of the composite coating containing 3 wt.% baghdadite in a phosphate buffer solution (PBS), the corrosion rate decreased from 0.45 (for the AZ91 sample) to 0.11 mg/cm2&middot, h after seven days of immersion. To evaluate the apatite formation capability of specimens, samples were immersed in an SBF solution. The results showed that the samples were bioactive as apatite layers formed on the surface of specimens. The composite coating containing 3 wt.% baghdadite showed the highest apatite-formation capability, with a controlled release of ions, and the lowest corrosion rate in the SBF.

Hardystonite is currently recognized as a biocompatible bio-ceramic material for a range of medical applications. In this study, pure nanocrystalline hardystonite powder was prepared by mechanochemical synthesis of zinc oxide, silicate oxide, and egg shell in a planetary ball mill followed by sintering. It was found that pure nanocrystalline hardystonite powder formation occurred following 20 h of milling and subsequent sintering at 1000 ℃ for 3 h. Hardystonite scaffold was prepared by space holder method. The results showed that 3D porous scaffolds with pore sizes in the range of 200–300 μm, total and open porosity of 81 and 76%, respectively, with compressive strength and modulus of 0.35 and 10.49 MPa, were obtained. The average crystallite size of the prepared hardystonite powder and scaffold was measured to be 28 ± 3 and 79 ± 1 nm, respectively. The bioactivity of prepared scaffold was evaluated by simulated body fluid (SBF). Considering the results obtained, it seems that, manufactured scaffolds could be a good candidate for bone tissue engineering applications.

The aim of this study was to design and evaluate nano-hardystonite/polyamide 66 composites with close mechanical properties to the trabecular bone to prevent the stress shielding phenomenon for bone tissue engineering applications. This composite can be used as an intervertebral fusion cage to perform spinal fusion between vertebrae in the lumbar spine. The pure nano-hardystonite powder was fabricated by combustion method at 900 °C following by 5 h ball mill. The nano-hardystonite/Polyamide 66 and nano-hydroxyapatite/Polyamide 66 cage were prepared by injection molding method to compare the mechanical and biological properties. In this end, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the prepared powder and cage samples. Based on the results, the addition of 30% nano-hardystonite improved both mechanical and bioactivity properties. The optimum hardystonite/PA66 samples revealed the compressive strength and elastic modulus of 69.19 ± 0.89 MPa and 2.56 ± 0.5 GPa, respectively, compared to 53.45 ± 1.2 MPa and 3.45 ± 0.3 GPa in hydroxyapatite/PA66 sample, respectively. In addition, observation of the superior apatite formation ability of hardystonite/PA66 compared to hydroxyapatite/PA66 indicated that it can be used as a spinal vertebrae replacement material.

Porous ceramic scaffolds are synthetic implants, which support cell migration and establish sufficient extracellular matrix (ECM) and cell-cell interactions to heal bone defects. Hydroxyapatite (HA) scaffolds is one of the most suitable synthetic scaffolds for hard tissue replacement due to their bioactivity, biocompatibility and biomimetic features. However, the major disadvantages of HA is poor mechanical properties as well as low degradability rate and apatite formation ability. In this study, we developed a new method to improve the bioactivity, biodegradability and mechanical properties of natural hydroxyfluorapatite (HFA) by applying two-step coating process including ceramic and polymer coats. The structure, morphology and bioactivity potential of the modified and unmodified nanocomposite scaffolds were evaluated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The scaffold with optimized mechanical properties was HFA-30 wt%HT (HT stands for hardystonite) with a total porosity and pore size of 89 ± 1 and 900–1000 µm, respectively. The compressive modulus and strength of HFA (porosity ~ 93 ± 1) were improved from 108.81 ± 11.12–251.45 ± 12.2 MPa and 0.46 ± 0.1–1.7 ± 0.3 MPa in HFA-30 wt%HT sample, respectively. After applying poly(e-caprolactone fumarate) (PCLF) polymer coating, the compressive strength and modules increased to 2.8 ± 0.15 and 426.1 ± 15.14 MPa, respectively. The apatite formation ability of scaffolds was investigated using simulated body fluid (SBF). The results showed that applying the hardystonite coating improve the apatite formation ability; however, the release of ions increased the pH. Whereas, modified scaffolds with PCLF could control the release of ions and improve the apatite formation ability as well.

In this work, an attempt was made to synthesize Al2O3/Al3Ni hybrid reinforcement particles in Al-matrix to fabricate an AMC using stir casting technique. The molten metal was stirred while NiO powder was injected into the melt using blowing inert argon. During the production process, aluminothermy reaction took place explosively. The reaction products were alumina as the first reinforcements and pure nickel metal. This reaction was followed by the formation of eutectic structure of (Al3Ni)eut at 1113 K. Adiabatic temperature of aluminothermy reaction was obtained 1923 K. A reaction occurs between aluminum and nickel at the melting point of aluminum during the solidification and Al3Ni intermetallic compound is formed which acts as the second reinforcement. The presence of Al2O3 and Al3Ni in the matrix was verified by EDS/XRD analysis. Significant increase happened in UTS, hardness, and microhardness values. It is due to the presence of created reinforcement particles uniformly dispersed in Al matrix.

This paper presents an optimization approach for the removal of lead ions (Pb+2) by nano-hydroxyapatite powder form adsorbents that were produced from bovine bone by mechanical activation method. The Taguchi method was implemented for designing the experiments by considering four controllable factors including (1) ball milling time (A), (2) the initial concentration of lead ions (B), (3) initial pH of the solution (C); and (4) the adsorbent dosage (D), each factor at four different levels. According to the ANOVA analysis results, the removal efficiency of the lead ions was predominantly influenced by the adsorbent dosage (38.2%) and the initial lead ions concentration (23.64%), whereas the effect of initial pH of the solution was ignorable and the ball milling time had a mild contribution of 14.79%. The total optimum adsorptive lead ions removal of 100% was achieved by optimization process at operating conditions of Co = 180 mg L− 1, ball milling time = 2 h, pH = 3, and adsorbent dosage = 0.15 g. The Langmuir isotherm model fitted to the equilibrium results with good accuracy and a maximum sorption capacity of 200 mg g−1 was predicted by the model for the hydroxyapatite adsorbent ball milled for 2 h.

Bredigite has been recently evaluated as a biodegradable ceramic with high mechanical strength, biocompatibility, bioactivity and excellent cell behavior. The objective of this research was to fabricate a nanostructured bredigite scaffold for bone repair and restoration via the space holder technique. The crystallite size, phase composition, particle size, pore morphology and pore size distribution of the scaffold were characterized using X-ray diffraction, as well as transmission and scanning electron microscopy. The results showed the fabrication of a highly interconnected porous scaffold, with a total porosity of about 86%, a pore size of about 400–600 μm, and the compressive strength of about 1.1 MPa. The prepared scaffold with nanosized structure and high porosity level leading to a high specific surface area could be used as an ideal scaffold for bone regeneration in bone tissue engineering applications.

A bioactive hardystonite (HT) - diopside (Dio) Nano-composite scaffold was fabricated by the space holder method. The structure, morphology and bioactivity potential of the Nano-composite scaffolds were examined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The scaffold with optimized mechanical properties was HT-15 wt%Dio that had a total, interconnected porosity, micro and macro pore size of 77 ± 1%, 71 ± 1%, 40–80 μm and 400–500 μm, respectively, and a compressive modulus and strength and crystallite size of 45.45 MPa, 1.655 MPa and 41 nm, respectively. The feasibility of the produced scaffold for bone tissue engineering application was evaluated using simulated body fluid (SBF). A range of characterization techniques was applied to confirm the deposition of Hydroxyl carbonated apatite (HCA) deposition on the surface of HT-15%Dio scaffold following 7 days in SBF. Overall, results suggest that HT-15 wt%Dio Nano-composite scaffold with improved mechanical properties, pore size, porosity content and apatite formation ability can be a promising candidate for bone tissue engineering applications.

A413 aluminum matrix composites reinforced with short carbon fibers (CSFs) were produced using a combination of vortex and squeeze casting processes and the effects of reinforcement volume fraction and reinforcement coating on density, porosity, reinforcement distribution and mechanical properties of the produced composites were studied. The results showed that increasing the volume fraction of CSFs led to decreased density and increased porosity of the cast composites. Distribution of uncoated CSFs in the matrix of the reinforced samples was poor and most of the fibers were in agglomerated bundle form. Utilization of coated CSFs resulted in a rather uniform distribution of the reinforcement in the matrix. Mechanical properties of squeeze cast composites fabricated using uncoated CSFs improved by increasing the reinforcement volume fraction up to 2% and decreased beyond it. Mechanical properties of the squeeze cast composites fabricated using coated CSFs improved steadily by increasing the reinforcement volume fraction up to 3%. Ultimate tensile strength and hardness values of the composites reinforced with 3 vol% coated CSFs increased by more than 100% and 60%, respectively, in comparison with those of the monolithic cast sample.

Despite the wide application of polycaprolactone (PCL) for bone tissue engineering application, its poor cellular interactions have resulted in the development of various strategies for surface modification. This paper established a surface modification approach based on gelatin immobilization on the PCL-3 wt. % diopside fibrous membrane. Moreover, the effects of swelling time on the amounts of immobilized gelatin were evaluated. Results demonstrated that gelatin was successfully immobilized within PCL-diopside membrane. Increasing swelling time from 5 to 30 min resulted in enhanced gelatin content. Moreover, while increasing swelling time upon 20 min did not significantly change the mechanical properties of gelatin-immobilized fibrous membranes, they reduced after 30 min swelling which might be due to the enhanced fiber and pore sizes as well as noticeably higher amount of immobilized gelatin within the membranes. Moreover, the hydrophilicity, biodegradation and bioactivity of PCL-3 wt. % diopside membrane significantly improved via gelatin immobilization. Finally, cellular behavior promoted because of the hydrophilic amino and carboxyl groups in the immobolized gelatin structure. Overall, our study suggested that gelatin immobilized PCL-diopside fibrous membranes could potentially be used to develop clinically revenant constructs for bone tissue engineering.

Porous baghdadite scaffold has received great attention as a candidate for bone tissue engineering application due to its remarkable bioactivity, biocompatibility, and good bone formation ability. A few studies have been focused on improving the mechanical properties of baghdadite scaffolds. Recently, space holder method has been introduced as a new and viable technique to prepare bioceramic scaffolds with interconnected pores and suitable mechanical properties. In this study, for the first time, 3D baghdadite scaffolds with interconnected porosity were produced using space holder method. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were utilized to characterize various specimens. The baghdadite scaffolds were sintered at various temperatures in the range of 1250-1350°C for 3h. The compressive strength and compressive modulus measured to be in the range of 0.05-0.52MPa and 2.1-121.5MPa, respectively. The results showed that nanostructured baghdadite scaffolds with a crystallite size of about 32nm, 75% porosity and pores size in the range of 200-500µm can be successfully fabricated after sintering at 1350°C for 3h. Simulated body fluid (SBF) was used to evaluate the apatite formation ability of the scaffolds. The results showed the formation of an apatite layer on the scaffold surface which can be considered as a bioactivity criterion.

Mechanical activation (MA) is an efficient method to synthesize nano-structured materials. This is the first report of successful synthesis of monticellite-akermanite nanocomposite from talc, calcium carbonate and magnesium carbonate powders. The raw materials were milled for 10 min, 2, 5, 10, and 20 h and then annealed in order to obtain monticellite-akermanite nanocomposite powder. The obtained powder was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated preparation of monticellite-akermanite nanocomposite powder with crystallite sizes about 30.76 ± 0.47 nm after 20 h mechanical alloying and sintering at 1200 °C for 1 h. Absence of enstatite, a phase that causes a reduction in mechanical and bioactivity properties, is an important feature of the prepared powder. The compacted samples of fabricated nanocomposite powder, sintered at 1300 °C for 3 h, exhibit significant improvements in compressive strength (60 ± 1.8 MPa) than single phase monticellite (43 ± 1.1 MPa) and hydroxyapatite (34 ± 1.4 MPa) which make it an appropriate candidate for bone tissue engineering applications.

The wettability, incorporation, and gravity segregation of TiC and B4C particles into molten aluminum are important problems in the production of Al-TiC and Al-B4C composites by the casting techniques. In order to solve these problems, different methods consisting of adding the Na3AlF6 and K2TiF6 fluxes and Mg (as the alloying element) into the molten aluminum and injection of the (Al + TiC)CP and (Al + B4C)CP composite powders instead of B4C and TiC particles are evaluated. In this work, the conditions of sample preparation, such as particle addition temperature, stirring speed, and stirring time, are determined after many studies and tests. Microstructural characterizations of samples are investigated by scanning electron microscopy equipped with energy dispersive spectroscopy (EDS) and X-ray diffractometry. The results show better distribution and incorporation of TiCp and B4Cp in aluminum matrix when the fluxes are used, as well as EDS analysis of the interface between the matrix and reinforcement-strengthened formation of the different phases such as Al4C3 in the Al-TiC composites and Al3BC, TiB2 in the Al-B4C composites.

A significant challenge in bone tissue engineering is the development of 3D constructs serving as scaffolds to fill bone defects, support osteoblasts, and promote bone regeneration. In this paper, highly porous (∼79%) nanostructured diopside/biphasic calcium phosphate (BCP) scaffolds with interconnected porosity were developed using various diopside contents via space holder method. X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques were utilized to evaluate different samples. Furthermore, the effects of scaffold composition on mechanical properties, bioactivity, biodegradability, and cytotoxicity were studied as well. The results showed that the produced scaffolds had an average pore size and density of 200–340 μm and 2.5 ± 0.3–1.8 ± 0.3 gr/cm 3 , respectively, depending on the diopside content. Besides, increasing the diopside content of scaffolds from 0 to 15 wt% enhanced the bioactivity, biodegradability, and compressive strength from 1.2 ± 0.2 to 3.2 ± 0.3 MPa, respectively. In addition, MTT assay also confirmed that the BCP15 scaffold (containing 15 wt% diopside) significantly promoted cell viability and cell adhesion compared to BCP0 scaffold. Overall, our study suggests that nanostructured diopside/BCP scaffolds with improved biological and mechanical properties could potentially be used for bone tissue engineering application.

Nature creates soft and hard ingredients revealing outstanding properties by adjusting the ordered assembly of simple primarily components from the nano- to the macro-scale. To simulate the important features of native tissue architecture, wide researches are being performed to develop new biomimetic custom-made composite scaffolds for tissue engineering. Here, we introduced a three-dimensional (3D) biomimetic scaffold based on the cuttlefish bone (CB) as a sacrificial template for bone tissue engineering. By combination of nylon 6 (N6), various amounts of baghdadite (BG) nanopowder and sacrificial template CB, a novel nanocomposite scaffolds was successfully developed with hierarchical microstructure and open pores in the range size in long and minor axis of 153–253 μm and 39–70 μm, respectively, depending on the BG content. In addition, incorporation of BG improved the mechanical properties of the scaffolds. Noticeably, the compressive strength and compressive modulus enhanced from 0.47 ± 0.05 to 1.41 ± 0.25 MPa and from 3.16 ± 0.14 to 6.23 ± 0.3 MPa, respectively. Moreover, results demonstrated that the incorporation of BG nanoparticles in the N6 matrix significantly improved bioactivity in simulated body fluid and increased degradation rate of N6 scaffold. Additionally, 3D nanocomposite scaffolds disclosed meaningfully excellent cellular responses. It is envisioned that the provided N6-BG nanocomposite scaffold might be a promising candidate for bone tissue engineering applications.

One of the significant challenges in bone tissue engineering is the fabrication of highly porous scaffolds with interconnected pores and appropriate mechanical properties. Artificial scaffolds which used in the field of medicine are usually made of single phase of polymer or ceramic. However, composition of these materials can produce the scaffolds with improve mechanical and biological properties.The aim of this study is to synthesize three-dimensional hardystonite-diopside (HT-Dio) porous scaffolds modified by polycaporolacton fumarate coating for low-load-bearing bone tissue engineering applications. The results showed that hardystonite scaffolds with 15 wt. % diopside and 6 w/v % polymer polycaporolacton fumarate (PCLF) had a significant bioactivity. The cell culture and cell attachment assay results revealed the well spreading of BMS cells on the surface of modified scaffolds which indicates the high biocompatibility of this scaffold. The modified scaffolds had a mean pore size, porosity, compressive strength, modules and toughness of 293.47 ± 5.51 μm, 74% ± 1.01, 3.37 ± 0.6 MPa, 151 ± 1.1 MPa and 31.3 ± 0.32 kJ/m3, respectively, which are in the appropriate range for spongy bone and hence can be a good candidate for bone tissue engineering applications.

One of the best methods to prevent wound infection and speed up wound healing is wound dressing based on nanofiber–polymer scaffolds, which have acceptable antimicrobial performance and appropriate skin regeneration capabilities. In this paper, the electrospinning method was applied to synthesize the polyvinylpyrrolidone-acrylic acid hydrogel (PVPA)–eggshell membrane (ESM)–reduced graphene oxide (rGO) nanosheets nanocomposite dressings with different reduced graphene oxide contents (0, 0.5, 1, and 2 wt.%). Thus, smooth nanofibers were fabricated, including a high amount of rGO, which reduced the fiber diameter. Based on the results, rGO played an important role in water impermeability. The results showed that by increasing the rGO concentration from 0.5 to 2 wt%, the contact angle value increased persistently. Results showed that compared to PVPA–ESM, the mechanical strength and strain of PVPA–ESM/1 wt% rGO significantly enhanced 28% and 23%, respectively. Incorporation of 1 wt% rGO enhanced swelling ratio from 875% for PVPA-ESM to 1235% after 420 min, while increasing the rGO to 2 wt% increased the degradation rate of the composites. According to the in vitro cell culture studies, PVPA-ESM wound dressings with 0.5–1 wt% rGO content enhanced PC12 cell viability compared to the wound dressings without rGO nanosheets. Generally, rGO–loaded PVPA-ESM nanofiber wound dressing can be considered as a potential candidate to be used in skin regeneration applications.

In this study, single-phase hardystonite (Ca 2 ZnSi 2 O 6 ) nanopowder was synthesized by combustion synthesis method from aqueous solution of Calcium nitrate, Zinc nitrate and Tetraethyl orthosilicate. In order to characterize the obtained powders, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used. The effect of sucrose concentration on the purity and morphology of the obtained hardystonite powder, and its initial annealing temperature was investigated. The optimum sucrose to metal ratio was found to be 2:1. The average particle size and the maximum crystallite size of the produced hardystonite nanopowder were 220 and 40 nm, respectively.

Hardystonite is currently recognized as a biocompatible bio-ceramic material for a range of medical applications. In this study, pure nano-crystalline hardystonite powder was prepared by mechanochemical synthesis of calcium carbonate, zinc oxide and silicate oxide in a planetary ball mill followed by sintering. A range of techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were applied to fully characterize the obtained powders. The effect of time and sintering temperature on the formation mechanism of nano-hardystonite was studied. It was found that pure nano-crystalline hardystonite powder formation occurred following 20 h of milling and subsequent sintering at 900 °C for 3 h. The measured crystallite and agglomerate particle size were found to be 28 ± 2 and 191 ± 3 nm, respectively. The two-step sintering processing was also applied for the preparation of bulk hardystonite. The compressive strength and elastic modulus of bulk hardystonite with 75.5 ± 3% relative density were approximately 121 ± 2 MPa and 27 ± 4 GPa, respectively.