Quaternary Supramolecular Nanoparticles as a Photoerasable Luminescent Ink and Photocontrolled Cell-Imaging Agent

Photoswitchable luminescent supramolecular assemblies based on cyclodextrins have attracted considerable attention owing to their potential applications as smart materials, but most of the assemblies reported to date emit green or blue light with low contrast and high interference. In this study, novel photoluminescent red-luminescent quaternary supramolecular nanoparticles (2) are constructed from a dithienylethene derivative (1), a beta-cyclodextrin-functionalized ruthenium complex (Ru-HOP-CD), Pluronic F-127, and cetrimonium bromide. Compared with the binary assembly 1@Ru-HOP-CD, the quaternary nanoparticles exhibit high fluorescence resonance energy transfer efficiency, with Ru-HOP-CD acting as the donor and 1 as the acceptor. Owing to the reversible photoswitched interconversion of the two forms of the dithienylethene component, the fluorescence of the nanoparticles could be switched on/off by irradiation with UV or visible light, both in solution and in the solid state. As a result, the nanoparticles could be used as a photoerasable red-luminescent ink and as a photocontrolled cell-imaging agent. These functional nanoparticles can be expected to be useful in the fields of information security and biology.