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Bone tissues, with their porous structure and the crucial role of producing and releasing blood elements into the bloodstream, can act as a suitable candidate for drug delivery stations in all parts of the body. Making an appropriate osteoconductive scaffold with drug delivery is the basis of this study for designing such materials. In this research, bone scaffolds containing drugs and magnetite nanoparticles were designed and produced for bone tissue approaches. As a new class of treatment for bone defects or deformity, calcium silicate ceramics (CSC) have been able to attract a lot of attention among researchers as a viable solution. With the incorporation of metal oxides (like Fe3O4: magnetite nanoparticles; MNPs) into the base binary xCaO-ySiO2-MgO as well as the substitution of calcium ions, CSCs can be fabricated. In the current work, the scanning electron microscope (SEM) and X-ray diffraction (XRD) technique were used to determine the phase and morphology of the porous scaffolds for dental fracture. The observation shows that the compressive strength and elastic modulus increase from 0.9 to 1.76 MPa and 59 to 81 MPa, respectively. The SEM images proved that the porosity dimensions were reduced from sample 0 wt% to sample 15 wt% (From 85 to 70%). Also, the absorbance test was found to be increased from 0 to 15 wt% sample in the PBS immersion solution. The obtained results indicated that the samples with a maximum of 10 wt% MNPs might release the drug more comfortably, which can be reported as a suitable candidate for bone tissue application.

One of the well-known ways to produce porous scaffolds or special three-dimensional (3D) micro-nanostructures is using the 3D printing technique. This technique requires a suitable computerized model of the scaffold using computer-aided design software or the computed tomography. The 3D printer fabricates a product by using a digital file and creates a layer-by-layer physical sample. Integrating different technologies and materials into one operational procedure can produce 3D tissue engineering scaffolds with enhanced properties. There are different tissue engineering strategies, including cell-based, factor-based, and scaffold-based strategies. In scaffold-based tissue engineering, 3D scaffolds are one of the most important applications of 3D printers, especially in medical science. In this article, a review of 3D printers, suitable for the production of soft and hard tissue engineering with different technologies is performed and several 3D printing techniques are described. Moreover, the pros and cons, and limitations of the 3D printing technique are discussed.

In this work, a novel porous bio-nanocomposite material containing the commercial nanocrystalline hydroxyapatite (n-HA) composed using single-walled carbon nanotubes (SWCNTs) with different weight fractions (0, 2.5, 5, and 7.5 wt%) is fabricated via a space holder technique for bone tissue engineering applications. The hydroxyapatite (HA) presents a weak mechanical performance which the addition of the SWCNT can enhance the mechanical strength of the matrix. The manufactured n-HA-SWCNT bio-nanocomposite samples are then coated by gelatin-ibuprofen (GN-IBO) bio-polymer with a dip-coating method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) are employed for the phase characterization and surface morphology analysis of the fabricated bio-nanocomposite specimens. The mechanical properties, the rate of drug release, and biological characteristics of the specimens with and without SWCNTs are investigated. After that, the nonlinear instability and vibration responses of an axially loaded plate-form bone implant made of the manufactured n-HA-SWCNT bio-nanocomposite samples coated with GN-IBO thin layers are simulated through a sandwich-plate model and based upon the experimentally extracted mechanical properties. The obtained results indicate the presence of SWCNT and n-HA in the composition due to the fuzzy metamorphism or degradation. It is found that by increasing the amount of SWCNTs, the mass density of the fabricated bio-nanocomposite samples reduces, but the porosity and strength of them are higher than those of the pure n-HA. Therefore, it is expected that these newly manufactured bio-nanocomposites have an excellent capability for bone formation with better bonds with surrounding tissues.

Bone regeneration is a growing and relatively effective treatment in most bone disease treatments. Adverse effects associated with conventional transplantation techniques have led to advanced bone tissue engineering. The purpose of this study is to produce a bone scaffold, made of sodium alginate (Na-Alg) based scaffold, with the addition of wollastonite-graphene nanosheet (WS-GS) with similar mechanical properties to normal bone. First, the Na-Alg-WS-GS nanocomposites are fabricated using freeze-drying technique in which GS is used as additives with different weight percentages (0, 1, 2 and 3 wt%). The fabricated nanocomposite scaffolds are tested and analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyzes. The maximum tensile strength, lowest decrease in sample area and stress yield is tested using mechanical testing. Then, the biological response in the biological environment, pH and weight changes after immersion in simulated body fluid (SBF) and phosphate buffered saline (PBS) is determined. The results show that the sample with 1 wt% GS has an appropriate capacity for reconstitution in the biological solution. The SEM shows an appropriate porosity of the scaffolds and a uniform distribution of GS in the polymeric matrix. The SEM images shows that as the amount of GS increases, the swelling capacity of the nanocomposites rises, regarding the weak bonding of GS and polymeric matrix. Additional amount of GS leads to increase in the tensile strength with the sample containing 1 wt%, however increasing of GS may decreases the mechanical performance of the structure. To gain the optimal combination of scaffold with the best mechanical and biological properties, the Global Criterion Method (GCM) is utilized. The obtained results show that the prepared nanocomposites are suitable for further development in tissue engineering and can be suitable for the bone substitutes application with desirable mechanical performance.

Having excellent biocompatibility and apatite mineralization as well as efficient mechanical properties makes bredigite as one of the most attractive bioceramics. A beam-type porous biological implant in a 3D-printed architecture is designed with micron pore size. The surface properties, morphology, and size of the composed powders are evaluated using Scherrer and Williamson-Hall equation. The effect of MNPs deposition into the bredigite bioceramics and correlation with temperature effect on roughness of the prepared bio-nanocomposite are also investigated for hyperthermia application potential. The composed powders are characterized by x-ray diffraction, and then scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis (weight change, TGA), and atomic force microscopy are utilized to evaluate the surface topography. The resonance response is the tendency of a bone scaffold to respond at prominent amplitude while the frequency of its oscillations is equal to the structure’s natural frequency of vibration. Therefore, based on the obtained mechanical properties via the experimental approach for the bio-nanocomposite material, an analytical solution based upon the multiple-timescale method is carried out to analyze the nonlinear primary resonance of a 3D-printed porous beam-type biological implant under uniform-distributed load. According to SEM observations, there are hard agglomerates in the bredigite-magnetite nanoparticles (Br-MNPs) bio-nanocomposite material with low weight fraction of MNPs. However, they are broken down by increasing the amount of MNPs. Also, it is displayed that for lower MNPs weight fraction, the height of jump phenomenon related to the nonlinear resonance response is maximum and minimum for, respectively, irregular and mesoporous shapes of morphology, but their associated forcing amplitudes related to the bifurcation points are minimum and maximum, respectively.

In the present article, a new size-dependent panel model is established incorporating the both hardening-stiffness and softening-stiffness small scale effects jointly with electrostatics and magnetostatics to study analytically the buckling and postbuckling behavior of smart magneto-electro-elastic (MEE) composite nanopanels under combination of axial compression, external electric and magnetic potentials. To this end, the nonlocal strain gradient elasticity theory in conjunction with the Maxwell equations is applied to the classical panel theory to develop a more comprehensive size-dependent panel model including simultaneously the both nonlocality and strain gradient size dependency. With the aid of the virtual work’s principle, the size-dependent differential equations of the problem are derived. The attained non-classical governing differential equations are solved analytically by means an improved perturbation technique within the framework of the boundary layer theory of shell buckling. Explicit analytical expressions associated with the nonlinear axial stability equilibrium paths of the electromagnetic actuated smart MEE composite nanopanels including nonlocality and strain gradient micro-size dependency are proposed. It is displayed that the nonlocal size effect leads to reduce the buckling stiffness, while the strain gradient size dependency causes to enhance it. Moreover, it is found that by applying a negative electric field as well as positive magnetic field, the influences of the nonlocal and strain gradient size effects on the critical buckling load of an axially loaded MEE composite nanopanel are more significant.

Zn-substituted cobalt ferrite nanoparticles with different zinc contents (Co1 − x Zn x Fe2O4, x = 0.25, 0.5, 0.75) were prepared through a novel combustion method and subsequent milling process. A magnetostriction test was conducted to investigate the migration of Co2+ ions away from the octahedral sites to confirm the decrease of the anisotropy as a result of the increase of the Zn content. The single domain and superparamagnetic behaviors in the obtained samples were analyzed, and their variations by the increase of Zn content were compared. The variations of anisotropy in the vicinity of various Zn contents were accessed, and the specific absorption rate of the obtained samples was estimated. Linear response theory showed that the ratio of the anisotropy energy to the thermal energy, as a dimensionless anisotropy parameter (σ), can have a key role in the specific absorption rate of any magnetic material in hyperthermia applications.

In the current study, bio-nanocomposites scaffolds including natural hydroxyapatite (n-HA) composed with different weight fractions of copper oxide nanoparticles (CuO-NPs) are fabricated using the space holder technique. After that, the manufactured samples are coated with gelatin polymer loaded with ibuprofen drug. Via experimental methods, the mechanical properties (fracture toughness and compressive strength) of n-HA-CuO bio-nanocomposite scaffolds are achieved corresponding to various weight fractions of the CuO-NPs. Also, the electrical conductivity and cell viability of the fabricated scaffolds are evaluated using the scan electron microscope (SEM) and X-ray diffraction (XRD) technique. Thereafter, based upon the extracted mechanical properties, nonlinear mechanical behaviors of beam-type implants made of the prepared n-HA-CuO bio-nanocomposites are predicted analytically. The cell viability and electrical conductivity evaluation demonstrate that on the free surface of all bio-nanocomposite scaffolds, there is a thin layer of apatite carbonate; however, the thickness of this layer in the sample containing 5wt% CuO-NPs is lower than other ones. It is seen that the adherence of ibuprofen's penetration into the gelatin polymer is weak which leads to two explosive release stages. For the lower weight fraction of CuO-NPs, the release of ibuprofen becomes significant.

Due to their colossal dielectric constant (CDC), $$\hbox {RFeO}_{3}$$RFeO3, orthoferrite ceramics (R = rare earth metal) have recently attracted much attention. In the present research, the dielectric constants of $$\hbox {RFeO}_{3}$$RFeO3 orthoferrite ceramics, whether with or without CDC, have been simulated. The type of synthesis method, the type of R material, temperature, and frequency as the effective parameters on the dielectric behavior are introduced to the model. Another input parameter is the ratio of $$\hbox {Fe}^{+2}/\hbox {Fe}^{+3}$$Fe+2/Fe+3 peak area (in the XPS diagram), which is the most important parameter that affects the CDC behavior. Initially, a colossal database is formed by means of WebPlotDigitizer software and 2930 experimental data, and then the simulation is carried out through gene expression programming. Two case studies are also performed on $$\hbox {PrFeO}_{3}$$PrFeO3 and $$\hbox {NdFeO}_{3}$$NdFeO3 orthoferrite ceramics to validate the accuracy of the presented model. $$\hbox {PrFeO}_{3}$$PrFeO3 exhibits significant CDC behavior whereas the $$\hbox {NdFeO}_{3}$$NdFeO3 ceramic samples possess little CDC property, both of which were precisely simulated by the model. Two-dimensional tenth-degree equations resulting from the model predict the dielectric constant variations accurately.

In low carbon steels, dissolution and precipitation of the second phases such as carbides and nitrides during annealing cycles can affect the final structure and properties of the materials. The interaction of above processes depends on parameters such as reheating temperature, heating rate, annealing temperature, soaking time and finishing temperature in hot rolling stage before cold rolling. The effects of heating rate and annealing temperature on the microstructure and hardness were investigated. Two heating rates for annealing temperatures of 550, 610 and 720 °C were applied on cold-rolled specimens and St-14 low carbon steel, which were immediately quenched after isothermal annealing. The intercept method was used to measure average grain sizes. However, resulted microstructures are different for the two heating rates. While pancaked structures were observed in specimens annealed with low heating rate, in samples annealed with high heating rate, equiaxed microstructures were observed. Vickers micro-hardness values decreased at all temperatures, which were more significant at higher temperatures. At longer annealing time, signs of increase of hardness values were detected. All results and observations consistently suggest that a precipitation process has occurred concurrently with restoration processes during annealing. In addition, the energy dispersive spectroscopy analysis resulted from transmission electron microscopic micrographs have proved that the nano particles precipitated in grain boundaries are AlN.