Peripheral nerves are exposed to physical injuries usually caused by trauma that may lead to a significant loss of sensory or motor functions and is considered as a serious health problem for societies today. This study was designed to develop a novel nano bioglass/gelatin conduit (BGGC) for the peripheral nerve regeneration. The bioglass nanoparticles were prepared by sol-gel technique and characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis. The interfacial bonding interaction between the nano-bioglass and gelatin in the developed conduits was assessed by FTIR. The surface morphology and pore size of the nanocomposite were investigated through scanning electron microscopy with the pore size of the conduits being 10-40 μm. Biocompatibility was assessed by MTT assay which indicated the BGGC to have good cytocompatibility. The guidance channel was examined and used to regenerate a 10 mm gap in the right sciatic nerve of a male Wistar rat. Twenty rats were randomly divided into two experimental groups, one with the BGGC and the other being normal rats. The gastrocnemius muscle contractility was also examined at one, two and three months post-surgery in all groups using electromyography (EMAP). Histological and functional evaluation and the results obtained from electromyography indicated that at three months, nerve regeneration of the BGGC group was statistically equivalent to the normal group (p > 0.05). Our result suggests that the BGGC can be a suitable candidate for peripheral nerve repair.

Abstract:We developed collagen (COL) and collagen/beta tricalcium phosphate (COL/b-TCP) scaffolds with a b-TCP/collagen weight ratio of 4 by freeze-drying. Mouse bone marrowderived mesenchymal stem cells (BMMSCs) were cultured on these scaffolds for 14 days. Samples were characterized by physicochemical analyses and their biological properties such as cell viability and alkaline phosphatase (ALP) activity was, also, examined. Additionally, the vascularization potential of the prepared scaffolds was tested subcutaneously in Wistar rats. We observed a microporous structure with large porosity (95-98%) and appropriate pore size (120-200 mm). The COL/b-TCP scaffolds had a much higher compressive modulus (970 6 1.20 KPa) than pure COL (0.8 6 1.82 KPa). In vitro model of apatite formation was established by immersing the composite scaffold in simulated body fluid for 7 days. An ALP assay revealed that porous COL/b-TCP can effectively activate the differentiation of BMMSCs into osteoblasts. The composite scaffolds also promoted vascularization with good integration with the surrounding tissue. Thus, introduction of b-TCP powder into the porous collagen matrix effectively improved the mechanical and biological properties of the collagen scaffolds, making them potential bone substitutes for enhanced bone regeneration in orthopedic and dental applications.

An exosome is a nano vesicle that buds from the endosomal compartment; it is produced and released by all kinds of mammalian cells. This vesicle contains a variety of proteins, lipids, mRNAs and miRNAs. These components are specific to the origin of the exosomes and contribute to cell-cell communications. Recently, it has been reported that a few single cell eukaryotic pathogens such as Cryptoccoccus neoformance and Leishmania major and donovanican secrete an exosome and influence the host immune system. In addition, it has been observed that cells infected by intracellular pathogens are capable of secreting an exosome which is involved in the fate of the infection. Furthermore, retroviruses recruit the host`s endosomal compartments in order to generate viral vesicles which are similar to the exosome. Most of the exosomes involved in infectious biology can either spread or limit an infection based on the type of pathogen and its target cells. Hence, an exosome may be an appropriate candidate for a vaccine therapy in prophylaxis and treatment.

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.