Heavy Atom‐Free Nanomicelle Photosensitizer Constructed From Cyclotriphosphazene Scaffold

ABSTRACT Photosensitizers, which can be activated by light excitation and convert molecular oxygen into reactive oxygen species, are an important component of light‐based phototherapeutic treatments. PSs are generally conjugated unsaturated organic molecules containing heavy atoms. The disadvantages of these structures, such as their low solubility in water and high dark toxicity, are the most obvious bottlenecks in biological applications. Herein, we successfully fabricated new water‐soluble photosensitizers that do not contain heavy atoms, investigated their structural analysis, determined their photophysical characteristics, and their singlet oxygen production ability in organic and aqueous media under light excitation. The orthogonal BODIPY unit and its cyclotriphosphazene derivative had strong absorption ability at 509 nm, high molar absorption coefficients and a light‐resistant molecular structures. Also, the compounds were able to produce singlet oxygen in organic media. We formed water soluble nanomicelle of the orthogonal BODIPY and its cyclotriphosphazene derivative with Tween 80. The new nanomicelles enabled efficient singlet oxygen production in aqueous medium under light irradiation. This study may offer new insight into the preparation of water‐soluble photosensitizers for phototherapeutic applications.