Abstract:
Novel amino-functionalized graphene crosslinked collagen based nerve conduit having appropriate electric
(3.8 ± 0.2 mSiemens/cm) and mechanical cues (having young modulus value of 100–347 kPa) for stem cell
transplantation and neural tissue regeneration was fabricated using cryogelation. The developed conduit has
shown sufficiently high porosity with interconnectivity between the pores. Raman spectroscopy analysis revealed the increase in orderliness and crosslinking of collagen molecules in the developed cryogel due to the
incorporation of amino-functionalized graphene. BM-MSCs grown on graphene collagen cryogels have shown
enhanced expression of CD90 and CD73 gene upon electric stimulation (100 mV/mm) contributing towards
maintaining their stemness. Furthermore, an increased secretion of ATP from BM-MSCs grown on graphene
collagen cryogel was also observed upon electric stimulation that may help in regeneration of neurons and
immuno-modulation. Neuronal differentiation of BM-MSCs on graphene collagen cryogel in the presence of
electric stimulus showed an enhanced expression of MAP-2 kinase and β-tubulin III. Immunohistochemistry
studies have also demonstrated the improved neuronal differentiation of BM-MSCs. BM-MSCs grown on electroconductive collagen cryogels under inflammatory microenvironment in vitro showed high indoleamine 2,3 dioxygenase activity. Moreover, macrophages cells grown on graphene collagen cryogels have shown high CD206
(M2 polarization marker) and CD163 (M2 polarization marker) and low CD86 (M1 polarization marker) gene
expression demonstrating M2 polarization of macrophages, which may aid in tissue repair. In an organotypic
culture, the developed cryogel conduit has supported cellular growth and migration from adult rat spinal cord.
Thus, this novel electro-conductive graphene collagen cryogels have potential for suppressing the neuro-inflammation and promoting the neuronal cellular migration and proliferation, which is a major barrier during the
spinal cord regeneration.
