PCL-PANi_GEL Nanofibrous Scaffolds Potential in Stem Cell Tissue Engineering

Background: The structure of biocompatible scaffolds is one of the biggest concerns of tissue engineers. Ideally, a scaffold should mimic structural and biological functions of extra-cel-lular matrix (ECM); both in terms of physical structure and chemical component. Scientists have found that nanofibrous scaffolds can provide a suitable environment for cell attach-ment, proliferation and differentiation and thus, play an im-portant role in tissue engineering. Gelatin is a biocompatible, biodegradable and a natural protein that is derived from colla-gen which is a main component of ECM. Polycaprolactone is a semi-crystalline, biodegradable soluble polymer and as a result, it has stimulated a lot of research on its potential and applica-tions in tissue engineering. Conductive polymers, due to their direct electrical stimulation capabilities, have received a great deal of attention. In this study, a variety of aligned and ran-dom PCL-PANI-GEL nanofibrous scaffolds were electrospun to determine their potential for tissue engineering regards. In addition, the osteogenic differentiation of MSCs cultured on the prepared scaffolds was investigated.Materials and Methods: PCL-PANI-GEL nanofibrous scaf-folds were prepared by Electrospinning, using a bi-electrospun method in order to achieve a feasible outcome. The morphology of nanofibrous scaffolds were observed and studied by SEM imaging. The porosity of bimodal foams was measured using a specific gravity bottle based on Archimedes’ Principle. Tensile properties were evaluated by an Instron Tensile Testing Appara-tus (5566-Applied Science Co., Ithaca, NY). In order to evalu-ate the viability of nanofibrous scaffolds, MTT assay as well as Acridine Orange staining tests were performed. Furthermore, to fully investigate the fibers’ potential for tissue engineering, os-teogenic differentiation of MSCs were performed. MSCs were seeded on nanofibers and after 14 days of differentiation, Alka-line Phosphatase activity, Alizarin Red Staining and Calcium Content test were performed to evaluate the fibers’ potential for stem cell differentiation.Results: Two candidates were chosen from the 6 fabricated na-nofibers. SEM imaging showed that the latter 2 were suitable for further tests. FTIR spectra of PCL-PANI-GEL nanofibers confirmed the chemical characterization of electrospun na-nofibers. MTT results supported the biocompatibility of the scaffolds. Then, MSCs were cultured on the scaffolds and then, differentiated to osteoblasts. Alkaline Phosphatase activity, Alizarin Red Staining and Calcium Content test confirmed the nanofibers potential for stem cell differentiation.Conclusion: In conclusion, we were able to reach an appropri-ate setup for PCL, Gel and PANI combination. Additionally, PANI-PCL-GEL electrospun fibers could be used as an appro-priate scaffold for efficient regeneration of bone defects. These synthetic nanofibers show promising applications in bone tissue engineering. Various assessments such as ALP activity, calcium content, alizarin red, mineralization staining and SEM micro-graphs demonstrated that the random and aligned electrospun scaffolds are appropriate for MSCs osteogenesis. In the future, these scaffolds can be used in in vivo analysis which will have a positive effect on bone healing in critical-size bone defects.

Keywords:

Nanofiberous Scaffolds , Stem Cell , Tissue Engineering