Visible-Light Controlled Release of a Fluoroquinolone Antibiotic for Antimicrobial Photopharmacology

Owing to the dwindling arsenal of antibiotics, new methodologies for their effective and localized delivery are necessary. The use of optical control over delivery of drugs, also known as photopharmacology, has emerged as an important option for the spatiotemporally controlled generation of drugs and bioactive molecules. In the field of antimicrobial photopharmacology, most strategies utilize ultraviolet light for triggering release of the antibiotic. The use of such short wavelength light may have limitations such as phototoxicity. Here, a small molecule that is activated by visible light to release a fluoroquinolone, a broad-spectrum antibiotic, is reported. A boron-dipyrromethene, which is sensitive to cleavage at 470 nm, was used, and levofloxacin was used as a model fluoroquinolone. BDP-Levo was found to undergo cleavage in the presence of visible light to release the active antibiotic. Using growth inhibitory studies in Gram-positive as well as Gram-negative bacteria, the efficacy of BDP-Levo is demonstrated. Together, our study demonstrates that visible light can be used for optical control over antibiotic release and lays the foundation for visible-light-mediated antimicrobial photopharmacology.