A photodynamic color sensor using diacetylene vesicles for the rapid visualization of singlet oxygen

Abstract

Despite therapeutic benefits of singlet oxygen (1O2), the development of reliable 1O2 detection methods is challenging due to its short lifespan and fast reactivity. Herein, we report a photodynamic color sensor for visualizing photoinduced 1O2 using a 10,12-pentacosadiynoic acid (PCDA) vesicle and a mini singlet oxygen generator (miniSOG). The miniSOG produced 1O2 by photoactivation, which subsequently reacted with the PCDA vesicle, resulting in a rapid color change from colorless monomeric PCDA to blue-colored polydiacetylene (PDA) vesicles (from yellow to green in the miniSOG-mixed solutions) through electron delocalization-mediated polymerization. Therefore, the color change from PCDA to PDA enabled the rapid and simple detection of photoinduced 1O2 and its scavengers on a microplate. Notably, the PCDA vesicles exhibited better sensitivity and stability for photoinduced 1O2 than classical chromogenic reagents. Along with the unique chromatic property and structural versatility of PCDA, we suggest that our approach is highly suitable for visualizing 1O2 in a rapid and simple way.