Abstract: Current study encourages the differentiation of human endometrial stem cells into osteoblast-like cells using osteogenic media for potential bone tissue engineering purposes. A biomimetic nanocomposite scaffolds based on GEL/calcium phosphate were fabricated and behavior of differentiated osteoblast cells was evaluated after seeding on this scaffold. Prepared scaffolds were assessed in terms of attachment, alkaline phosphatase activity, gene expression and proliferation of osteoblast cells. The matrix mineralization was approved by alizarin red and the treated cultures with osteogenic media and BMP2 were positive for osteopontin and osteocalcin antibodies. RT-PCR confirmed presence of osteopontin, osteonectin and alkaline phosphatase mRNA after differentiation in EnSCs-derived osteoblast-like cells. Also, it has been shown that the biomimetic nanocomposites possess appropriate chemical and physical properties to support the attachment and proliferation of differentiated osteoblast cells.
Abstract: Bone matrix consists of two major phases at the nanoscale: organic and hydroxyapatite. Nanotechnology as a diverse and interdisciplinary area of research has the capacity to revolutionize many areas of applications such as bone tissue engineering. Nano Hydroxyapatite/Gelatin composite has higher osteoblast attachment and proliferation than micro-sized ones, and shorter culturing period and lower cell seeding density compared to pure gelatin. A nanostructured scaffold was fabricated by 3 methods for bone repair using nanohydroxyapatite and gelatin as the main components. Its biocompatibility, alizarin red test on the 14(th) and 21(st) days, gene expression on the 21(st) day in in-vitro using and histomorphometry after 4 and 8 weeks post-implantation in the rat were investigated. Cultured unrestricted somatic stem cells used for in vitro study showed an excellent level of cell attachment to the scaffold. Cells induced more osteoblast differentiation on the scaffold than in 2D cell culture. Osteoblast differentiation and bone regeneration results of in vitro and in vivo investigation on scaffold were extremely significant, better than control and treatment groups. These effects could be attributed to the shape and size of nano HA particles and good architecture of the scaffold. The results confirm the feasibility of bone regeneration using synthesized scaffold as a temporary bone substitute.
Abstract: In this study, double diffusion method in a physiologically relevant environment was used to prepare a biomimetic gelatin-amorphous calcium phosphate nanocomposite scaffold. The precipitated calcium phosphate within gelatin as well as produced nanocomposite scaffolds were characterized by the commonly used bulk techniques. The results showed that nanocomposite scaffolds were porous with three-dimensionally interconnected microstructure, pore size ranging from 150 to 350 μm. Porosity was about 82% and nanocrystalline precipitated minerals were dispersed evenly among gelatin fibers. A mineral containing amorphous calcium phosphate and brushite precipitate was formed within the gelatin matrix at 4°C. After incubation in SBF solution at 37°C for 5 days, the mineral phase was transformed to nanocrystalline hydroxyapatite. It should be noted that precursor phases inside a scaffold implanted into the body can result in biomimetic conversion of precursors to hydroxyapatite that is very similar to the bone mineral and has a profound level of biocompatibility. Thus, our results highlight the potential use of engineered biomimetic bone tissue scaffolds in the bone tissue repair process.
Abstract: In this study, a nano-structured scaffold was designed for bone repair using hydroxapatite and gelatin as its main components. The scaffold was prepared via layer solvent casting combined with freeze-drying and lamination techniques and characterized by the commonly used bulk techniques. The biocompatibility and osteoconductivity of this scaffold and its capacity to promote bone healing were also evaluated. Osteoblast-like cells were seeded on these scaffolds and their proliferation rate, intracellular alkaline phosphatase (ALP) activity and ability to form mineralized bone nodules were compared with those osteoblasts grown on cell culture plastic surfaces. Also, the scaffolds were implanted in a critical bone defect created on rat calvarium. Engineering analyses show that the scaffold posses a three dimensional interconnected homogenous porous structure with a porosity of about 82% and pore sizes ranging from 300 to 500 μm. Mechanical indices are in the range of spongy bones. The results obtained from biological assessment show that this scaffold does not negatively affect osteoblasts proliferation rate and improves osteoblasts function as shown by increasing the ALP activity and calcium deposition and formation of mineralized bone nodules. In addition, the scaffold promoted healing of critical size calvarial bone defect in rats. It could be concluded that this scaffold fulfills all the main requirements to be considered as a bone substitute.
Abstract: In this research, new bioactive nanocomposite scaffolds were successfully developed using poly(ε-caprolactone) (PCL), cross-linked gelatin and nanoparticles of hydroxyapatite (HAp) after testing different solvents and methods. First, HAp powder was synthesized via a chemical precipitation technique and characterized. Then, the nanocomposites were prepared through layer solvent casting combined with freeze-drying and lamination techniques. According to the results, the increasing of the PCL weight in the scaffolds led to the improvement of the mechanical properties. The amount of ultimate stress, stiffness and also elastic modulus increased from 8 MPa for 0% wt PCL to 23.5 MPa for 50% wt PCL. The biomineralization study revealed the formation of an apatite layer on the scaffolds after immersion in simulated body fluid (SBF). The Ca-P ratios were in accordance to nonstoichiometric biological apatite, which was approximately 1.67. The in vitro biocompatibility and cytocompatibility of the scaffolds were tested using mesenchymal stem cells (MSCs), and the results indicated no sign of toxicity, and cells were found to be attached to the scaffold walls. The in vivo biocompatibility and osteogenesis of these scaffolds in the animal experiments is also under investigation, and the result will be published at the end of the study.
Abstract: During the last decades, there have been several attempts to combine bioactive materials with biocompatible and biodegradable polymers to create nanocomposite scaffolds with excellent biocompatibility, bioactivity, biodegradability and mechanical properties. In this research, the nanocomposite scaffolds with compositions based on PVA and HAp nanoparticles were successfully prepared using colloidal HAp nanoparticles combined with freeze-drying technique for tissue engineering applications. In addition, the effect of the pH value of the reactive solution and different percentages of PVA and HAp on the synthesis of PVA/HAp nanocomposites were investigated. The SEM observations revealed that the prepared scaffolds were porous with three dimensional microstructures, and in vitro experiments with osteoblast cells indicated an appropriate penetration of the cells into the scaffold's pores, and also the continuous increase in cell aggregation on the scaffolds with increase in the incubation time demonstrated the ability of the scaffolds to support cell growth. According to the obtained results, the nanocomposite scaffolds could be considered as highly bioactive and potential bone tissue engineering implants.
Abstract: In this study, a nanostructured scaffold was designed for bone repair using hydroxyapatite (HA) and gelatin (GEL) as its main components. Nanopowders of HA were synthesized, and together with GEL, used to engineer a 3-dimensional nanocomposite combining 3 techniques of layer solvent casting, freeze-drying, and lamination. The results show that the scaffold possesses a 3-dimensional interconnected homogenous porous structure with a porosity of 82% and pore sizes ranging from 300 to 500 mum. It has also been shown that mechanical indices are in the range of spongy bones. Cultured osteoblast-like cells (SaOS-2) have shown an excellent level of cell attachment, migration, and penetration into the porosities of the nanocomposite scaffold. Here, we have shown that by a combination of widely available methods with simple experimental operations, nano-HA powders can be synthesized and used to make 3-dimensional HA/GEL nanocomposites in any desired shape, with mechanical properties comparable to spongy bone.
