Self-assembled dual-state emission nanoprobe for hypochlorous acid imaging in living cells.
Phenothiazine derivatives, with excellent photophysical properties and structural tunability, are commonly used as core skeletons for fluorescent probes targeting reactive oxygen species like hypochlorous acid (HClO). However, the optical characteristics of most reported phenothiazine-based probes are predominantly characterized by either aggregation-caused quenching (ACQ) or aggregation-induced emission (AIE), limiting their practical biological sensing applications. Dual-state emission (DSE) designates fluorophores that maintain significant fluorescence whether in solution or in solid/aggregated states, effectively overcome these drawbacks, yet DSE-based HClO probes remain rarely reported. Herein, we rationally design and synthesize a novel phenothiazine-skeleton DSE fluorophore (PTZ-DNs), which spontaneously self-assembles into water-dispersible nanoparticles (PTZ-DNs NPs) to construct a DSE nanoprobe for HClO sensing and bioimaging. This self-assembled nanoplatform exhibits prominent performances, including favorable aqueous dispersibility, rapid HClO response (<10 s), superior long-term luminescent stability, and good biocompatibility. This work provides a design strategy to develop a DSE-based nanoprobe for detecting biologically relevant reactive species.