Preparation and application of multi-wavelength-regulated multi-state photoswitchable fluorescent polymer nanoparticles

The photoswitchable system with color and multi-state fluorescence changes is the key to the realization of advanced multi-level information storage, and its application potential has far exceeded the monochromatic fluorescent system. Herein, we introduced a novel multi-state photoswitchable fluorescent polymeric nanoparticles , which contains two energy-matched photoswitchable fluorescent molecules, i.e. diarylethene derivative (BH, donor) and spiropyran derivative (SPMA, acceptor), to construct a tunable fluorescence resonance energy transfer (FRET) system. By optimizing the feeding ratio of the two photochromic molecules to control the efficiency of energy transfer, the fluorescence of the nanoparticles can be reversibly switched among none, red, orange, and green by adjusting the wavelength of light stimuli. In addition, the nanoparticles display good water dispersibility , high brightness, fast responsiveness, excellent photoreversibility, and long-term fluorescence stability. We also verified that the system has great potential in optical data storage, multi-layer information encryption , and anti-counterfeiting.