Arginine-modified dual emission photoluminescent nanocrystals for bioimaging at subcellular resolution.

Bioimaging at a subcellular resolution to label cytoplasm and nucleus in living cell by just one photoluminescent nanoparticle has great application potential in bioresearch, preclinical diagnosis, screening, and image-guided therapy of life-threatening diseases. Herein, we report a novel arginine (Arg) functionalized ultra-small lanthanide oxyfluoride nanocrystals (LaOF) for simultaneously targeted imaging cell cytoplasm and nucleus. As-prepared Arg-modified PAA capped LaOF: 45%Ce, 15%Tb nanocrystals (LaOF:Ce,Tb@PAA@Arg) possessed high water dispersibility, ultra-small size (∼5.7 nm) and double emissions (green and red) with high quantum yield (40%). Such functionalized nanocrystals presented high cellular biocompatibility and were successfully used to label living cells with very high contrast. These functionalized nanocrystals also exhibited significantly higher photostability and brightness as compared to commercial dyes. Such the ultra-small size, high photostability and intensity, double emissions, excellent biocompatibility and targeted ability, make as-prepared functionalized nanocrystals particularly promising for cellular and subcellular bioimaging applications.