Spatiotemporal activation of molecules within cells using silica nanoparticles responsive to blue-green light

The spatiotemporal control of molecular function is important but there are currently few techniques for noninvasively controlling various types of molecules in live cells. Herein we developed nanoparticles with a boron dipyrromethene structure, which are responsive to blue-green visible light. Fluorophores (fluorescein, rhodamine B, and Nile blue A) encapsulated within the nanoparticles were released by irradiation for 3 min with visible light. Nanoparticles were internalised by HeLa cells without the aid of a cell-penetrating peptide, serving as vehicles for the delivery of cargo molecules to the cytoplasm. The release and activation of encapsulated molecules by visible light irradiation demonstrate a novel method for the spatiotemporal control of molecular function that can be used to activate molecules inside the skin that cannot be reached by UV light, which has limited tissue penetration.