Dye‐Sensitized Core/Shell Upconversion Nanoparticles for Detecting Nitrites in Plant Cells

A fluorescent nanoprobe is reported for rapid detection of nitrites (NO 2 − ) in plant cells. The probe is fabricated by linking neutral reds (NR) to the surface of upconversion fluorescent core/shell nanocrystalline with the bridging of polyethylene glycol (PEG) molecules. The fluorescence of upconversion nanoparticles (UCNPs) is stored by NR through fluorescence resonance energy transfer (FRET) under 980 nm excitation that can be released by...