A novel biodegradable electroactive polyurethane containing aniline pentamer (AP) was blended with polycaprolactone (PCL). The prepared blend (PB) and PCL were further fabricated in to scaffolds using a mixture of poly(ethylene glycol) and salt particles in a double porogen particulate leaching and compression molding methodology. Scaffolds held open and interconnected pores having pore size ranging from several μm to 150 µm. PB scaffolds had compression modulus and strength of 4.1 and 1.3 MPa, respectively. The conductivity of the scaffold was measured as 10(-5) ± 0.09 S .cm(-1) and preserved for at least 100 h post fabrication. Scaffolds supported neonatal cardiomyocytes adhesion and growth with PB showing more extensive effect on the expression of the cardiac genes involved in muscle contraction and relaxation (troponin-T) and cytoskeleton alignment (actinin-4). Our results highlight the potential of incorporation of AP as an electroactive moiety for induction of cardiomyocyte proliferation and repair of damaged heart tissue.

In this study porous gelatin scaffolds were prepared using in-situ gas foaming, and four crosslinking agents were used to determine a biocompatible and effective crosslinker that is suitable for such a method. Crosslinkers used in this study included: hexamethylene diisocyanate (HMDI), poly(ethylene glycol) diglycidyl ether (epoxy), glutaraldehyde (GTA), and genipin. The prepared porous structures were analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), thermal and mechanical analysis as well as water absorption analysis. The microstructures of the prepared samples were analyzed using Scanning Electron Microscopy (SEM). The effects of the crosslinking agents were studied on the cytotoxicity of the porous structure indirectly using MTT analysis. The affinity of L929 mouse fibroblast cells for attachment on the scaffold surfaces was investigated by direct cell seeding and DAPI-staining technique. It was shown that while all of the studied crosslinking agents were capable of stabilizing prepared gelatin scaffolds, there are noticeable differences among physical and mechanical properties of samples based on the crosslinker type. Epoxy-crosslinked scaffolds showed a higher capacity for water absorption and more uniform microstructures than the rest of crosslinked samples, whereas genipin and GTA-crosslinked scaffolds demonstrated higher mechanical strength. Cytotoxicity analysis showed the superior biocompatibility of the naturally occurring genipin in comparison with other synthetic crosslinking agents, in particular relative to GTA-crosslinked samples.

Finally these results suggest that this biomimetic model with fibrin may provide a vastly applicable 3D culture system to study the effect of anti-cancer drugs such as atrovastatin on tumor malignancy in vitro and in vivo and atorvastatin could be used as anticancer agent for glioblastoma treatment.

Various compositions and synthesis methods of biodegradable iron-based alloys have been studied aiming for the use of temporary medical implants. However, none is focused on nano-structured alloy and on adding antibacterial property to the alloy. In this study, new Fe-30Mn-(1-3)Ag alloys were synthesized by means of mechanical alloying and assessed for their microstructure, mechanical properties, corrosion rate, antibacterial activity and cytotoxicity. Results showed that the alloy with 3 wt% Ag content displayed the highest relative density, shear strength, micro hardness and corrosion rate. However, optimum cytotoxicity and the antibacterial activity were reached by the alloy with 1 wt% Ag content. The compositional and processing effects of the alloys' properties are further discussed in this work.

Mesenchymal stem cells (MSCs) are adult multipotent cells that due to their ability to homing to damaged tissues and differentiate into specialized cells, are remarkable cells in the field of regenerative medicine. It's suggested that the predominant mechanism of MSCs in tissue repair might be related to their paracrine activity. The utilization of MSCs for tissue repair is initially based on the differentiation ability of these cells; however now it has been revealed that only a small fraction of the transplanted MSCs actually fuse and survive in host tissues. Indeed, MSCs supply the microenvironment with the secretion of soluble trophic factors, survival signals and the release of extracellular vesicles (EVs) such as exosome. Also, the paracrine activity of EVs could mediate the cellular communication to induce cell-differentiation/self-renewal. Recent findings suggest that EVs released by MSCs may also be critical in the physiological function of these cells. This review provides an overview of MSC-derived extracellular vesicles as a hopeful opportunity to advance novel cell-free therapy strategies that might prevail over the obstacles and risks associated with the use of native or engineered stem cells. EVs are very stable; they can pass the biological barriers without rejection and can shuttle bioactive molecules from one cell to another, causing the exchange of genetic information and reprogramming of the recipient cells. Moreover, extracellular vesicles may provide therapeutic cargo for a wide range of diseases and cancer therapy.

Among various methods, nerve tissue engineering (NTE) is one of the applicable methods to reconstruct damaged nerve tissues. Electrospinning technique and biomaterials are often considered to fabricate fibrous tissue engineered conduits which have great similarity to the extracellular matrix on fiber structure. Polymer blending is one of the most effective methods for the production of new materials with outstanding features. In this study, conduit structures as main part of the peripheral nerve regeneration based on polymer blend nanocomposites poly(ε-caprolactone)/collagen/nanobioglass (PCL/collagen/NBG) were manufactured by electrospinning technique. Various properties of electrospun mats were investigated by using contact angle, tensile, degradation time, porosity, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and wide-angle X-ray scattering (WAXS). The SEM analysis was shown that size range and average pore size of polymer blend nanocomposite nanofibers were about 250-400 nm and 0.7 µm, respectively, with an optimum porosity of 62.5%. The XRD result was shown that synthesized nanoparticles of NBG had amorphous structures. Also, FTIR analysis indicated that good interaction between polymer-polymer macromolecules and polymer particles. The contact angle and tensile tests were indicated that electrospun webs showed good hydrophilicity and toughness properties. According to SEM, MTT assay and DAPI staining technique, the ability to support cell attachment and viability of samples were characterized. In vitro study indicated electrospun collagen/PCL/NBG nanofibrous conduit promoted Human Endometrial Stem cells (hEnSCs) adhesion and proliferation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1960-1972, 2017.

The current study aimed to enhance the efficacy of peripheral nerve regeneration using an electrically conductive biodegradable porous neural guidance conduit for transplantation of allogeneic Schwann cells (SCs). The conduit was produced from polylactic acid (PLA), multiwalled carbon nanotubes (MWCNTs), and gelatin nanofibrils (GNFs) coated with the recombinant human erythropoietin-loaded chitosan nanoparticles (rhEpo-CNPs). The PLA/MWCNTs/GNFs/rhEpo-CNPs conduit had the porosity of 85.78 ± 0.70%, the contact angle of 77.65 ± 1.91° and the ultimate tensile strength and compressive modulus of 5.51 ± 0.13 MPa and 2.66 ± 0.34 MPa, respectively. The conduit showed the electrical conductivity of 0.32 S cm and lost about 11% of its weight after 60 days in normal saline. The produced conduit was able to release the rhEpo for at least 2 weeks and exhibited favorable cytocompatibility towards SCs. For functional analysis, the conduit was seeded with 1.5 × 10 SCs and implanted into a 10 mm sciatic nerve defect of Wistar rat. After 14 weeks, the results of sciatic functional index, hot plate latency, compound muscle action potential amplitude, weight-loss percentage of wet gastrocnemius muscle and Histopathological examination using hematoxylin-eosin and Luxol fast blue staining demonstrated that the produced conduit had comparable nerve regeneration to the autograft, as the gold standard to bridge the nerve gaps. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1463-1476, 2018.

Context: The nervous system is the most important system of the body and damaging this system could be lethal for humans. Restoring the function of a damaged nervous system has always been a challenge due to the complexity of this system and its limited ability of regeneration. Furthermore, several obstacles exist in the repair process of the nervous system.Evidence Acquisitions: In the central nervous system (CNS) limited clearance of myelin and formation of inhibitory glial scars make regeneration difficult. There is no effective clinical treatment for damages in the CNS while current treatments focus on stabilization and prevention of further damage and consequently on rehabilitation and preparation of prosthetics and mechanical aids. In peripheral nervous system (PNS) damages, the management may be a nerve autograft or allograft while shortage of donors for nerves makes the situation difficult. Size inequality between the donor nerve and the recipient, danger of neuroma formation and occurrence of infectious diseases are other problems associated with PNS, while indeed complete recovery of function is still not common.Results: Several studies have illustrated that implying tissue engineering strategies for neural repair may lead to considerable improvements in damaged nervous tissues. The development of a scaffold that is similar to the natural extracellular matrix can provide an ideal environment for three dimensional cell cultures, which is a reason for neural tissue engineering success. The need to develop biocompatible and biodegradable material that supports neural tissue growth still exists.Conclusions: This article reviews different types of polymeric materials used in neural tissue engineering and mainly focuses on their properties and their advantages and disadvantages in neural regeneration