Imaging fluctuation of sulfite in mouse tumor and inflammation models with a novel quinoxaline-based fluorescent probe

In this work, a novel fluorescent probe, YT, was developed for monitoring the fluctuation of sulfite in biological applications. The quinoxaline moiety was chosen as the fluorophore to obtain the naked-eye signals in the green channel. The levulinate was selected to achieve the specific and relatively steady recognition reaction. Compared with the reported fluorescent probes for sulfite, YT indicated above moderate performances including remarkable and rapid response (120 folds, within 10 min), high sensitivity (limit of detection = 0.15 μM), and high selectivity. The detecting system showed a green emission and the fluorescence was stable within the pH range of 6–10. In addition, YT could be further applied into living cells and mouse models. Focusing on the serviceability in the breadth of application scope, we imaged the fluctuation of sulfite in both mouse tumor and inflammation models. In the xenograft model, YT could indicate the fluctuation of sulfite which was caused by both addition of exogenous sulfite and induction of different agents including sulfite donor, Na2S2O3, phorbol-12-myristate-13-acetate, and GSH. In the LPS-induced inflammation model, YT could visualize the dose-dependent increase of sulfite level (0–2 mg/mL). More than providing a practical fluorescent implement for monitoring sulfite, this work also raised informatic parameters for developing fluorescent tools into broadened animal models.