Development of Novel Scaffolds for Skeletal Muscle Tissue Engineering Applications

Abstract

Tissue Engineering (TE) is emerging as an effective way of curing tissue oriented disorders through new tissue regeneration. Recently graphene oxide (GO composed of graphene oxide nanoplatelets, GOnPs) is widely being used for electronic and biomedical applications because of its favourable physicochemical properties. The present thesis work focuses on the fabrication of electrospun GO-poly (ɛ-caprolactone, PCL) and GO-poly (lactic-co-glycolic acid, PLGA) composite scaffolds for myoblast proliferation and differentiation of human cord blood derived mesenchymal stem cells (hMSCs), which is novel and challenging. The GO surface possessing different hydrophilic groups allowed it to be well dispersed in the polymer matrices for making electrospun fibrous scaffold meshes. Addition of GO in these polymers enhanced mechanical property, hydrophilicity and electrical conductivity of the GO-polymer composites. Electrical conductivity of the GO-PCL and GO-PLGA scaffolds increased by about two orders of magnitudes (from ~5x10-9 to 2.3 x10-7 S/m2) with the addition of low GO concentration (within non-toxicity limit <20 µg/ml for human cells). Such enhancement of conductivity along with nanostructural surface morphology of GO improved the biocompatibility and cell viability of the developed scaffolds. GO-polymer composites showed percolation behavior at low GO concentrations (~0.79 and 0.76wt%, respectively, for GO-PCL and GO-PLGA). High resolution TEM (HRTEM) and Raman G and D peak values indicated the presence of GO in the composite scaffold messes. In-vitro cell culture study confirmed excellent myoblast differentiation of hMSCs on these electrospun composite scaffolds. The GO-PCL composite scaffolds with suitable mechanical properties, little higher hydrophilicity as well as conductivity and dielectric constant (associated with GO surface charge) compared to those of GO-PLGA, exhibited better myoblast differentiation and promoted self-aligned myotubes formation, which were evident by cell attachment (FESEM studies), viability and proliferation (WST-8 assay), Immunohistochemical analysis etc. Moreover, IGF-1 cell signalling pathway study done on GO-PCL scaffolds also indicated superiority of the GO-PCL scaffolds for skeletal muscle tissue regeneration. It was revealed, for the first time, that GO surface charge and significant enhancement of conductivity of the GO–polymer nanocomposite scaffolds, GO-PCL scaffold in particular, might be considered as potential candidates for the myoblast differentiation of hMSCs for the next generation human skeletal muscle tissue regeneration.