Near-infrared light-responsive upconversion substrate enables spatiotemporal control of mesenchymal stem cells adhesion and multilineage differentiation in vivo

Spatiotemporally precise control of mesenchymal stem cells (MSCs) differentiation remains an unmet challenge in regenerative medicine. Herein, we report a near-infrared (NIR)-responsive platform that integrates upconversion nanoparticle (UCNP)-functionalized substrates with host-guest photoresponsive chemistry (β-cyclodextrin/arylazopyrazole-RGD) to NIR spatiotemporally orchestrate MSCs adhesion, spreading, and lineage commitment with spatiotemporal precision. The UCNPs convert 808 nm NIR light into localized UV emissions, dynamically modulating azobenzene-cyclodextrin interactions and thereby tuning surface RGD ligand density via photoisomerization. Under low NIR intensities (0-0.5 W/cm²), augmented integrin-RGD binding drives robust focal adhesion assembly, actin cytoskeletal tension, nuclear YAP translocation, and osteogenic differentiation, as evidenced by 2-3 fold upregulation of BMP2, RUNX2, and ALP. Conversely, high-intensity NIR (1-2 W/cm²) induces RGD detachment, leading to suppressed cytoskeletal contractility and nuclear Lamin A/C expression, consequent cytoplasmic YAP retention, and activation of PPARγ-mediated adipogenesis, marked by 4-5 fold induction of PPARγ, C/EBPα, and FABP4. Most importantly, in vivo murine studies validate the platform's capacity for non-invasive, light-guided spatiotemporal regulation of MSCs adhesion, spreading, YAP signaling, and lineage specification (osteogenic vs. adipogenic), wherein differentiation thresholds (e.g., 1 W/cm²) correspond to clinically safe NIR exposure limits. This opto-material hybrid system effectively decouples photochemical stimulation to program MSC fate via mechanotransduction pathways, thereby providing a translatable strategy for the design of intelligent biomaterials towards personalized tissue regeneration.