Ex vivo expansion of hematopoietic stem cells has been explored in the fields of stem cell biology, gene therapy and clinical transplantation. Recently, we demonstrated the existence of a circulating myogenic progenitor expressing the CD133 antigen. The relative inability of circulating CD133+ stem cells to reproduce themselves ex vivo imposes substantial limitations on their use for clinical applications in muscular dystrophies. Here we report that the use of cluster-assembled nanostructured titanium dioxide (ns-TiO2) substrates, in combination with cytokine enriched medium, enables high-level expansion of circulating CD133+ stem cells in vitro. Furthermore, we demonstrate that expanded circulating CD133+ stem cells retain their in vitro capacity to differentiate into myogenic cells. The exploitation of cluster-assembled ns-TiO2 substrates for the expansion of CD133+ stem cells in vitro could therefore make the clinical application of these stem cells for the treatment of muscle diseases practical.