Illuminating Stem Cell Fate: Blue Light's Impact on Self-Renewal, Proliferation, Differentiation, and Genomic Stability in Mouse Embryonic Stem Cells

Embryonic stem cells (ESCs) are invaluable in regenerative medicine due to their pluripotency and self-renewal capacity. While chemical factors regulating ESCs are well-studied, the impact of physical cues like blue light (BL) remains unclear. We investigated the effects of BL (411–415 nm) on ESC growth, self-renewal, genetic stability, and differentiation. Low doses of BL (3.3 and 10 J/cm²) stimulated ESC proliferation without impairing self-renewal or increasing DNA damage, monitored via xCELLigence and homologous recombination assays. During differentiation into epidermal cells, BL exposure on day 0 or day 2 affected embryoid body integrity and altered the expression of pluripotency and epidermal markers (Oct4, Nanog, Krt8, Krt14). These findings suggest that BL can promote ESC proliferation while modulating differentiation outcomes, providing a potential tool for optimizing ESC culture in regenerative applications.