Ultrathin MoS2-MoO3-x heterojunction nanosheets with unique features were introduced as biocompatible, non-cytotoxic, and visible light-sensitive stimulator layers for the controlled differentiation of human neural progenitor cells (hNPCs) into nervous lineages. hNPC differentiation was also investigated on reduced graphene oxide (rGO)-containing scaffolds, that is, rGO and rGO/MoS2-MoO3-x nanosheets. In darkness, hNPC differentiation into neurons increased on MoS2-MoO3-x by a factor of 2.7 due to the excellent biophysical cues and further increased on rGO/MoS2-MoO3-x by a factor of 4.4 due to a synergistic effect induced by the rGO. The MoO3-x domains with antioxidant activity and LSPR absorption induced p-type doping in MoS2-MoO3-x. Under photostimulation, the hNPCs on the MoS2-MoO3-x exhibited higher differentiation into glial cells by a factor of 1.4, and the decrease in photo-electron current to hNPCs due to the induction of more p-type doping in the MoS2-MoO3-x. While the increase in neuronal differentiation of hNPCs on rGO/MoS2-MoO3-x by a factor of 1.8 was ascribed to the presence of rGO as an ultrafast electron transferor which quickly transferred photogenerated electrons to hNPCs before their transfer to free radicals, these results demonstrated the promising potential of MoS2-based scaffolds for applying in the controllable repair and/or regeneration of diseases/disorders related to the nervous system.
Keywords: MoS2 nanosheets; graphene oxide; molybdenum oxide; nanostructured scaffolds; stem cells; tissue engineering.