Highly photostable rylene-encapsulated polymeric nanoparticles for fluorescent labeling in biological system

Abstract Rylene dyes exhibit superior photophysical properties including outstanding chemical and photochemical stabilities as well as high fluorescence quantum yields (FQYs). However, the rylene chromophores have some limitations, such as high hydrophobicity and low solubility in aqueous solution, as a fluorescent tag for biological system. Herein, we present a general method to load the rylene dyes into triblock copolymer nanoparticles (NPs) and stabilize the core. The rylene dyes in confined hydrophobic core fairly preserve their FQYs in aqueous environment. Lumogen probe nanoparticles (PNPs) were prepared with four different commercial rylenes (Lumogen Violet, Yellow, Orange and Red) in the spectral region of visible and infrared (400 – 750 nm) and their photophysical properties were characterized. They exhibited enhanced photostability compared to commercial fluorescent dyes. Also the internalization of Lumogen PNPs in HeLa cell was confirmed by cell uptake test. These results indicate the Lumogen PNPs can be widely applicable in fluorescence detection and imaging such as flow cytometry and fluorescence microscopy.