Dyes@BNNT Nanohybrids for Photostable Fluorescence Imaging

Fluorescence is ubiquitous in life science and used in broad fields of research going from ecology to medicine. Among the most common fluorogenic compounds, dyes are being exploited in bioimaging for their outstanding optical properties across a broad range of wavelengths from the UV to the near-IR. However, dye molecules are often toxic to living organisms and photodegradable, giving limited time windows for in vivo monitoring. By encapsulating organic dyes inside a boron nitride nanotube (dyes@BNNT), we achieve a passivation of the dyes against photodegradation and chemical reaction. The dyes@BNNT nanohybrids contain aggregated and ordered dyes exhibiting strong photoluminescence with signal remaining stable and exempt of blinking over a time scale of more than 10^4 compared to free dyes. Our results also suggest reduced toxicity and exceptional chemical robustness even in harsh environments. The use of these 1D dyes@BNNT nanohybrids as fluorescence nanoprobes in bio-imaging is highlighted with in-vivo monitoring experiments on living Daphnia Pulex.