Intracellular photoswitchable neuropharmacology driven by luminescence from upconverting nanoparticles.

Photoswitchable drugs are small-molecule optical probes that undergo chromatically selective control of drug efficacy using, most often, UV-visible light. Here we report that luminescence produced by near-infrared stimulation of NaYF4:TmYb nanoparticles can be used for "remote control" of an azobenzene-based photochromic ion channel blocker of neurons in living brain slices.