Graphene oxide (GO) has attracted significant interest as a template material for multiple applications due to its two-dimensional nature and established functionalization chemistries. However, for applications toward stem cell culture and differentiation, GO is often reduced to form reduced graphene oxide, resulting in a loss of oxygen content. Here, we induce a phase transformation in GO and demonstrate its benefits for enhanced stem cell culture and differentiation while conserving the oxygen content. The transformation results in the clustering of oxygen atoms on the GO surface, which greatly improves its ability toward substance adherence and results in enhanced differentiation of human mesenchymal stem cells toward the osteogenic lineage. Moreover, the conjugating ability of modified GO strengthened, which was examined by auxiliary osteogenic growth peptide conjugation. Overall, our work demonstrates GO's potential for stem cell applications while maintaining its oxygen content, which could enable further functionalization and fabrication of novel nano-biointerfaces.