N-aminomorpholine-functionalized bromine-doped carbon dots for hypochlorous acid detection in foods and imaging in live cells

Scheme 1 Illustration of the synthetic procedure of Br-CDs-AM and the application in sensing HClO in food matrices and lysosomal imaging. [Display omitted] •Br-CDs with excellent photostability were synthesized by self-doping strategy.•Br-CDs-AM as a probe was made of Br-CD and N-aminomorpholine by substitution reaction.•HClO in milk, yogurt and meat samples were detected accurately (96.5 %–108 %).•• Br-CDs-AM can be used to locate lysosome and visualize HClO in live cells. Hypochlorous acid (HClO) is used in food preservation. However, excessive HClO can deteriorate nutritional composition of food, compromise its quality, and potentially induce various diseases. Consequently, the development of multifunctional fluorescent probes for the sensitive and selective detection of HClO is highly anticipated for food safety. In this work, we designed a nanoprobe using N-aminomorpholine (AM)-functionalized bromine-doped carbon dots (Br-CDs-AM) for sensing HClO. This nanoprobe exhibits pH stability, strong resistance to photobleaching, superior long-term photostability (12 weeks), high sensitivity (19.3 nM), and an ultrarapid response (8 s) for detecting HClO residues in food matrices with percentage recovery (96.5 %–108 %) and RSDs less than 5.34 %. In addition, extremely low cytotoxicity and outstanding biocompatibility enable the nanoprobe to be used primarily for lysosome tracking and rapidly visualizing HClO in live cells. Thus, this study provides a new pathway to design unconventional nanoprobes for food safety assessment and subcellular organelle-specific imaging HClO.