Bipolar Hemicyanine-Based Photodynamic Modulation of Type I Pathway for Efficient Sterilization and Real-Time Monitoring.

The development of photosensitizers with low oxygen dependence for generating type I ROS is in high demand to be able to treat pathogenic infections in hypoxic conditions. Here, we report a series of cationic bipolar hemicyanines (C3, C6, and C10) with alkyl linkers of varying lengths that are found to exclusively produce hydroxyl radicals and superoxide radicals with the aid of white light and that have different antibacterial abilities toward a variety of pathogens. Furthermore, hemicyanines could differentiate live from dead bacteria to track the status of pathogens in real time. It is expected that hemicyanines could be applied for combatting various microbial infections in hypoxia and real-time tracking.