Spheroid formation and neural induction in human adipose-derived stem cells on a chitosan-coated surface

The application of stem cells appears to have great therapeutic potential to facilitate nerve regeneration in patients with neurodegenerative disease or spinal cord injury. Human adipose-derived stem cells (hADSCs), a subset of multipotent mesenchymal stem cells, possess the great advantages of an abundant amount of cells, less ethical conflict and minimal invasive surgical procedures to obtain the cells. Chitosan, a naturally derived polysaccharide from chitin, has been widely studied to facilitate and guide the direction of nerve regeneration as a biomaterial for the neural tube. Chitosan also serves as a three-dimensional culture substrate to facilitate cellular sphere formation among various cells but is as yet unexplored in hADSCs. In this study, the ability of hADSCs to transdifferentiate from the mesenchymal into the neural lineage by seeding hADSCs on a chitosan-coated surface to form therapeutic cell spheres was investigated. The optimal seeding density (2 × 10⁴ cells/cm²) and harvesting time (72 h) to obtain sphere formation were determined by cell viability on a chitosan-coated surface. Expression of neural lineage markers was observed by immunofluorescent staining of nestin, neurofilament heavy chain and glial fibrillary acidic protein. The neural induction potentials were also provoked by replating spheres from primary to tertiary passages. The effect of neural induction in hADSCs on a chitosan-coated surface may help to provide cell sources for facilitating nerve regeneration in future clinical applications.