Optogenetic control of odontoblastic differentiation in dental pulp stem cells (DPSC)

Dental Pulp Stem Cells (DPSC) are sensitive to ionic and electrical cues governing mineralization. We developed a photo-responsive in vitro model using a synthetic optogenetic construct to test whether light-gated ion flux can modulate odontoblastic differentiation without biochemical induction. A commercially available, non-clinical-grade DPSC line was transfected with a modular light-gated cation channel (Opto-Ca 2+ Switch) driven by a mineralization-associated synthetic promoter. Cells were embedded in gelatin methacrylate (GelMA)–carbon-dot composites providing internal light scattering. Illumination (470 nm, 0.6 mW cm −2 , 30 min day −1 ) was delivered for 14 days. Odontoblastic progression was monitored through alkaline phosphatase (ALP) activity, calcium deposition, and dentin sialophosphoprotein/dentin matrix acidic phosphoprotein 1 (DSPP/DMP1) transcription. Illuminated cultures displayed a threefold increase in ALP and enhanced calcium deposition relative to dark controls. Quantitative polymerase chain reaction (qPCR) revealed significant up-regulation of DSPP (≈4.5 × ) and DMP1 (≈3.8 × ). Confocal imaging confirmed transient intracellular Ca 2+ oscillations upon light exposure. The mineralized matrix exhibited oriented, dentin-like lamellae within the GelMA network. Optically gated ion channels provide a tunable strategy for light-directed odontoblastic differentiation. The system demonstrates a route toward photo-regulated biomineralization and light-responsive dental scaffolds that unify biophotonics and regenerative dentistry.