Naphthalimide dyes as fluorescent probes for emerging applications in medical diagnostics and therapeutics: a review

Naphthalimide dyes have become an important class of fluorophores since they combine structural adaptability with favorable photophysical characteristics as well as good compatibility with biological systems. These qualities make them strong candidates for use in medical diagnostics and therapeutics. Their tunable emission, photobleaching resistance, and capability of undergoing different processes like intramolecular charge transfer, twisted charge transfer, and photoinduced electron transfer have contributed to their applications in biosensing and cancer imaging, photodynamic therapy and multifunctional drug delivery. Recent advances have led to the extension of this family into near infrared and two-photon designs for deep tissue imaging, activatable probes having high selectivity, nanocarrier formulations and targeted theranostics. Work is also well underway to integrate naphthalimide probes with artificial intelligence platforms and multiplexed sensing approaches as well and opens up the door to real-time monitoring and systems-level diagnostics. Despite these improvements, there are still critical hurdles to overcome, such as optimising compatibility with the body, enhancing light penetration through tissue, controlling pharmacokinetics and traversing the regulatory pathways. This review focuses on innovations in structural design, biomedical field and clinical translation of the naphthalimide derivatives, and further presents future research directions in smart probes, precision medicine, and economics in healthcare. Overall, naphthalimide scaffolds seem to be well poised to make a contribution in the future of molecular diagnostics and personalised therapeutics.