A generic platform for self-illuminating unimolecular systems enabling photodynamic therapy

Abstract

This work delineates a generic platform, 1-((1,4-dioxo-1,2,3,4-tetrahydrophthalazin-6-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl 2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoate, (conjugate 1), for self-illuminating unimolecular systems that can both glow in physiological pH (7.4) and enable photodynamic therapy (PDT) in highly acidic environments. It is noteworthy that conjugate 1 induces chemiluminescence upon treatment with KO2 at physiological pH. Also, it is remarkable that this straightforward design effectively boosts the singlet oxygen generation. Most strikingly, conjugate 1 can function as a photosensitizer even in highly acidic environments. Crucially, conjugate 1 shows in vitro phototoxicity when illuminated for 30 min. Furthermore, the capability of conjugate 1 as a self-illuminating PDT agent is explored. To our delight, we noted that conjugate 1 can eliminate 79% of cancerous cells upon chemical excitation being triggered in vitro. The data render its efficiency as a self-illuminating anticancer therapy agent. Last but not least, conjugate 1 can successfully inhibit the growth of bacteria. Also, we found that the shelf life of the acidic beverages can be extended from 2 days to ≅ 6–7 days after photodynamic sterilization with conjugate 1. To our best knowledge, this is the first example of luminol-based self-illuminating unimolecular systems enabling PDT for anticancer and antibacterial activities.