1,8-Naphthalimide-derived reactivity-based fluorescent probes for detection and imaging of H2S

Abstract

Hydrogen sulfide (H₂S) is both an important biological signaling molecule and a toxic environmental pollutant, making its precise detection essential for biomedical research and environmental monitoring. Among the various sensing platforms available, amino-1,8-naphthalimide (Nap)-based fluorescent probes have become powerful tools for real-time H₂S detection due to their high sensitivity, excellent selectivity, biocompatibility, and quick response. Nap fluorophores offer several inherent advantages—including strong and tunable emission, prominent intramolecular charge-transfer (ICT) characteristics, large Stokes shifts, and easy structural modification—making them especially attractive as scaffolds for developing activity-based probes. This review highlights recent developments in Nap-derived fluorescent sensors for H₂S detection, categorizing the probes based on their reactive sites and sensing mechanisms, such as thiolysis, reduction, and nucleophilic substitution. For each category, we explore structure–function relationships, photophysical properties, sensing performance, and practical applications in biological and environmental settings. Finally, we address current challenges and future directions in designing next-generation Nap-based probes with enhanced ratiometric responses, targeted subcellular localization, two-photon excitation capabilities, and improved suitability for in vivo imaging. Overall, this review offers a comprehensive perspective to guide the rational development of innovative fluorescent tools for accurate and efficient H₂S detection.