A coumarin-based fluorescent probe for NIR imaging-guided photodynamic therapy against <i>S. aureus</i>-induced infection in mouse models

Abstract

A coumarin-based viscosity-responsive fluorescent probe (HZAU800) was designed and synthesized. The probe, containing a strong electron-donating and rigid group on the 7-position of coumarin and a rhodamine derivative containing an oxonium ion on 3-position, could not only shift the emission wavelength to near-infrared region (NIR, <i>λ</i>_em = 800 nm) but also deliver a good PDT effect due to its high rigid planarity. The NIR fluorescence of HZAU800 can be lighted up in the <i>S. aureus</i>-infected region due to its high viscous environment. Under the laser's irradiation at 690 nm, the PDT effect was effectively triggered up, and the antibacterial evaluation <i>in vitro</i> and <i>in vivo</i> was successfully carried out. This study not only offers a new strategy for constructing coumarin-based phototherapy agents but also facilitates the exploration of the next generation of antibacterial materials based on coumarin architectures.