In Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaffolds have been utilized to repair damaged bone tissue. For bone tissue engineering, synthetic scaffolds should have acceptable mechanical properties, in addition to the required biological properties. In this regard, the finite element simulation is used to predict the mechanical properties of porous bone scaffolds as one of the most common methods for reducing the experimental tests, because the acquisition of mechanical properties of such scaffolds is very time-consuming and expensive. Due to the widespread use of hydroxyapatite (HA) in the manufacture of bone scaffold composites, the mechanical properties of HA-wollastonite scaffold composites are obtained by laboratory tests and finite element methods. Comparison of the simulation of finite element analysis (FEA) and the experimental results indicate the success of the FEA simulation. In conclusion, new finding satisfied expectations as being suitable for mechanical and biomaterial aspect of a porous scaffold which is proven by laboratory tests and FEA simulations. Due to that fact, the result of this study can be employed to obtain scaffolds well-suited for bone implementations. پرونده مقاله

The porous scaffold provides a temporary environment for bone growth and facilitates cell adhesion, cell growth and differentiation. In the present study, polymeric scaffolds were designed and fabricated via fused deposition modelling (FDM) method for orthopedic defect approaches using polycaprolactone (PCL) and polylactic acid (PLA) polymer. The prepared scaffold was coated with Chitosan-Hydroxyapatite (HA) as a reinforcement. The application of PLA, PCL and HA received attention of orthopedic surgeons to accelerate the bone healing. However, the comparison between the compression strength value of these scaffolds required more investigation and advance mechanical testing. In this study, we coat the novel PCL and PLA scaffold with chitosan-HA composite to mimic with humans' body. In the next stage, the mechanical strength and the biological response of the specimen were examined. Then, the morphology and phase characterization of the materials were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique. The apatite formation and weight change test were performed on the porous scaffold which showed proper hydrophilicity. The microstructure of the porous scaffold was simulated using the Abaqus simulation with the extracted data from the experimental work. At the end, it was concluded that the most suitable scaffold was fabricated made of PLA filament and coated with chitosan-hydroxyapatite nanocomposite which can be useful choice for bone tissue engineering. پرونده مقاله

Many people suffer from skin injuries due to various problems such as burns and accidents. Therefore, it is essential to shorten treatment time and providing strategies that can control the progression of the wound that would be effective in wound healing process and also reduce its economic costs. Materials and Methods: The present study aimed to prepare a nanocomposite dressing (NCD) composed of carboxymethyl chitosan (CMC), and Fe2O3 nanoparticles by a method called freeze-drying (FD) technique. The biological response in the physiological saline was performed to determine the rate of degradation of NCD in phosphate buffer saline (PBS) for a specific time. Results & Discussion: The obtained results demonstrated that the wound dress was porous architecture with micron-size interconnections. In fact, according to the results, as the magnetite nanoparticles amount increases, the porosity increases too. On the other hand, the tensile strength was 0.32 and 0.85 MPa for the pure sample and the sample containing the highest percentage of magnetic nanoparticles, respectively. Besides, the cytotoxicity of this nanocomposite was determined by MTT assays for 7 days and showed no cytotoxicity toward the growth of fibroblasts cells and had proper in vitro biocompatibility. The obtained results revealed that NCD had remarkable biodegradability, biocompatibility, and mechanical properties. Therefore, NCD composed of CMC and Fe2O3 nanoparticle was introduced as a promising candidate for wound healing applications. Conclusion: According to the obtained results, the optimum NCD specimen with 5 wt% Fe2O3 has the best mechanical and biological properties. پرونده مقاله

Abstract. Since osteomyelitis is a serious and dangerous disease, it requires immediate treatment with antibiotics or bone substitute replacement in orthopedic surgeries. Therefore, a porous polymeric-ceramic was fabricated using hydroxyapatite (HA) and polymethylmethacrylate (PMMA) composed with elastin as an ideal scaffold for bone tissue engineering applications. The current study is aimed at investigating the effects of various amounts of elastin biopolymer on porous bio-nanocomposite scaffold using the freeze-drying (FD) technique. The morphology and phase analysis of the prepared scaffold are analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. The biological performance of the porous tissue is evaluated in simulated body fluid (SBF) and sodium chloride (SC) solution. The tensile test is used to measure the elastic modulus and tensile strength of the porous tissue before soaking in the SBF. The obtained result is simulated using micromechanical model from the experimental values. The elastic modulus of samples decreases from 1.18 MPa to 0.69 MPa, and porosity evaluation is in the range of 70-85% with addition of 10 wt% and 15 wt% elastin to PMMA-HA bio-nanocomposite. The biological behavior indicates that a thick apatite layer precipitate on the surface of the sample with 10 wt% elastin beside increases alkaline group with constant pH concentration. According to the obtained porosity and elastic modulus results, suitable micromechanical model is assessed. The comparison of micromechanical model is assessed, and error rate was less than 10%; therefore, optimum model is introduced as the best micromechanical model for porous bone substitute. پرونده مقاله

Objective (s) Due to the natural bone microstructure, the design and fabrication of porous ceramic scaffold nanocomposite materials coated with thin layer of a natural polymer can provide an ideal scaffold for bone tissue engineering. This study aimed to fabricate multi-component porous magnetic scaffolds by freeze- drying (FD) technique using a gelatin polymer layer coated with a gentamicin drug. Materials and Methods: Magnetic nanoparticles (MNPs) can be manipulated and controlled by an external magnetic field gradient (EMFG) that is inherent in the magnetic field's permeability within human tissues. In the present work, unlike the usual ceramic/polymer composite scaffold, the ceramic components and the magnet were placed together in the reaction medium from the beginning, and bioceramics were replaced in the composite polymer network and then coated with a drug-loaded polymer. To evaluate the morphology of the magnetic scaffold, scanning electron microscopy (SEM) was utilized to evaluate the microstructure and observe the porosity of the porous tissue. Results and Discussion: After analyzing the SEM images, the porosity of the scaffolds was measured, which was similar to the normal bone architecture. Also, the porosity value increased from 55% to 78% with addition of MNPs to the based matrix. Conclusion: The results of this study showed that gentamicin-gelatin-coated on porous ceramic-magnet composite scaffolds could be used in bone tissue engineering and apply for treatment of bone tumors, because of their similarity to the bone structure with good porosity. پرونده مقاله

The application of porous bio-nanocomposites polymer has greatly increased in the treatment of bone abnormalities and bone fracture. Therefore, predicting the mechanical properties of these bio-nanocomposites is very important prior to their fabrication. Investigation of mechanical properties like (elastic modulus and hardness) is very costly and time-consuming in experimental tests. Therefore, researchers have focused on mathematical methods and new theories to predict the artificial synthetic bone for orthopedic application. In this paper, porous bio-nanocomposites synthetic bone including nanocrystalline Hydroxyapatite (HA) nanoparticles and Titanium oxide (TiO2) containing (0 wt%, 5 wt%, 10 wt%, and 15 wt% of TiO2) as reinforcements and the biocompatible polycaprolactone (PCL) polymer as the matrix has been used for the fabrication of PCL-HA-TiO2. Then, the mechanical test was conducted on the samples and the extracted value from the experimental test was compared with the analytical model using molecular dynamics (MD) method. Finally, these properties were compared with the Dewey micromechanics theory, and the error rate between the experimental method and the Dewey theory was reported. It was found that as the porosity percentage increased in the sample three-phase in composites, the model has a higher error in this theory. Then, due to the importance of hydroxyapatite in the fabrication of bone scaffolds, the obtained results of mechanical properties (Elastic modulus and Poisson’s ratio) have been analyzed statistically. The application of these equations in the rapid prediction of Elastic Modulus and Poisson's ratio of the synthetic bone scaffolds made of hydroxyapatite is highly recommended. پرونده مقاله

Since osteomyelitis is a serious and dangerous disease, it requires immediatetreatment with antibiotics or bone substitute replacement in orthopedic surgeries.Therefore, a porous polymeric-ceramic was fabricated using hydroxyapatite(HA) and polymethylmethacrylate (PMMA) composed with elastin as an idealscaffold for bone tissue engineering applications. The current study is aimed atinvestigating the effects of various amounts of elastin biopolymer on porous bionanocompositescaffold using the freeze-drying (FD) technique. The morphologyand phase analysis of the prepared scaffold are analyzed using scanning electronmicroscope (SEM) and X-ray diffraction (XRD) techniques. The biologicalperformance of the porous tissue is evaluated in simulated body fluid (SBF) andsodium chloride (SC) solution. The tensile test is used to measure the elasticmodulus and tensile strength of the porous tissue before soaking in the SBF. Theobtained result is simulated using micromechanical model from the experimentalvalues. The elastic modulus of samples decreases from 1.18 MPa to 0.69 MPa,and porosity evaluation is in the range of 70-85% with addition of 10 wt% and 15wt% elastin to PMMA-HA bio-nanocomposite. The biological behavior indicatesthat a thick apatite layer precipitate on the surface of the sample with 10 wt%elastin beside increases alkaline group with constant pH concentration. Accordingto the obtained porosity and elastic modulus results, suitable micromechanicalmodel is assessed. The comparison of micromechanical model is assessed, anderror rate was less than 10%; therefore, optimum model is introduced as the bestmicromechanical model for porous bone substitute. پرونده مقاله

Objective(s): Due to the natural bone microstructure, the design and fabrication ofporous ceramic scaffold nanocomposite materials coated with a thin layer of a naturalthe polymer can provide an ideal scaffold for bone tissue engineering. This study aimed tofabricate multi-component porous magnetic scaffolds by freeze-drying (FD) techniqueusing a gelatin polymer layer coated with a gentamicin drug.Methods: Magnetic nanoparticles (MNPs) can be manipulated and controlled byan external magnetic field gradient (EMFG) that is inherent in the magnetic field'spermeability within human tissues. In the present work, unlike the usual ceramic/polymer composite scaffold, the ceramic components, and the magnet were placedtogether in the reaction medium from the beginning, and bioceramics were replacedin the composite polymer network and then coated with a drug-loaded polymer. Toevaluate the morphology of the magnetic scaffold, scanning electron microscopy(SEM) was utilized to evaluate the microstructure and observe the porosity of theporous tissue.Results: After analyzing the SEM images, the porosity of the scaffolds was measured,which was similar to the normal bone architecture. The addition of gentamicin tothe gelation was investigated to monitor the drug delivery reaction in the biologicalenvironment. The magnetic properties of the sample were evaluated using thehyperthermia test for 15 seconds at the adiabatic conditions. Also, the porosity valueincreased from 55% to 78% with the addition of MNPs to the based matrix.Conclusions: The results of this study showed that gentamicin-gelatin-coated onporous ceramic-magnet composite scaffolds could be used in bone tissue engineeringand apply for treatment of bone tumors, because of their similarity to the bonestructure with good porosity. پرونده مقاله

Objective(s): Many people suffer from skin injuries due to various problems such asburns and accidents. Therefore, it is essential to shorten treatment time and providingstrategies that can control the progression of the wound that would be effective inwound healing process and also reduce its economic costs.Methods: The present study aimed to prepare a nanocomposite dressing (NCD)composed of carboxymethyl chitosan (CMC), and Fe2O3 nanoparticles by a methodcalled freeze-drying (FD) technique. The effect of different weight percentages ofFe2O3 (0, 2.5, 5, and 7.5 wt%) reinforcement on mechanical and biological propertiessuch as tensile strength, biodegradability, and cell behavior was evaluated. Also, theX-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used tocharacterize the soft porous membrane. The biological response in the physiologicalsaline was performed to determine the rate of degradation of NCD in phosphatebuffer saline (PBS) for a specific time.Results: The obtained results demonstrated that the wound dress was porousarchitecture with micron-size interconnections. In fact, according to the results, asthe magnetite nanoparticles amount increases, the porosity increases too. On theother hand, the tensile strength was 0.32 and 0.85 MPa for the pure sample and thesample containing the highest percentage of magnetic nanoparticles, respectively.Besides, the cytotoxicity of this nanocomposite was determined by MTT assays for 7days and showed no cytotoxicity toward the growth of fibroblasts cells and had properin vitro biocompatibility. The obtained results revealed that NCD had remarkablebiodegradability, biocompatibility, and mechanical properties. Therefore, NCDcomposed of CMC and Fe2O3 nanoparticles was introduced as a promising candidatefor wound healing applications.Conclusions: According to the obtained results, the optimum NCD specimen with 5wt% Fe2O3 has the best mechanical and biological properties. پرونده مقاله