Optical regulation of stem-cell differentiation by femtosecond-laser photostimulation

Stem-cell therapy is showing great potential in regenerative medicine for their inherent ability to self-renew and differentiate. Biochemical and genetic methods and 3D materials/structures have been developed and making great progress in controlling the development and differentiation of stem cells. One of the major remaining concerns is the invasion of those technologies. In this study, we demonstrate an all-optical and noninvasive approach to precisely induce the differentiation of adipose-derived stem cells (ADSCs) and cerebellar granule neuron progenitor (GNP) cells. We show that the single-time fast-flash of photostimulation by a tightly-focused femtosecond laser, without any optogenetics, can activate endogenous signaling pathways for stem-cell differentiation directly by multiphoton excitation. The significant upregulation of differentiation regulator RUNX2 and Osterix in ADSCs 7 days after photostimulation indicates the osteogenic differentiation of ADSCs. The differentiation was finally confirmed by Alizarin red staining 28 days after photostimulation. The differentiation of GNP cells in vitro and in vivo can also be induced by this method. This noninvasive optical technology hence provides an encouraging advance to activation of signaling pathways in cells and alternative to classic biochemical methods for stem-cell differentiation. This result also provides an optical choice with promising potential for clinical regenerative applications.