Green-Light-Activatable Penicillin for Light-Dependent Spatial Control of Bacterial Growth, Biofilm Formation, and <i>In Vivo</i> Infection Treatment

Our ability to prevent, treat, and cure bacterial infections is nowadays seriously threatened by the rise of (multidrug) antimicrobial resistance (AMR), and novel molecular approaches in the antibacterial arsenal are urgently needed. To fight the development of AMR, the field of photopharmacology aims to develop photoresponsive antimicrobials allowing for noninvasive activation of the drug only at the site needed, with spatiotemporal precision, reducing the bacterial exposure to the active antimicrobial in the environment. This study reports the development and application for the first time of a green-light-activatable variant of penicillin (<b>Penicillin-PPG</b>), designed through the incorporation of a photocleavable protecting group. Here, we demonstrate that <b>Penicillin-PPG</b> shows no antimicrobial activity in the dark, while it can be precisely activated through irradiation with green light. Furthermore, we show <b>Penicillin-PPG</b>'s utility to spatially control bacterial growth, achieve light-dependent inhibition of biofilm formation, and showcase the unprecedented usage of a photoactivatable antimicrobial <i>in vivo</i> in a small animal infection model. Furthermore, we apply <b>Penicillin-PPG</b> in combination with a λ-orthogonally photocaged bioactive compound to achieve photocontrol over antimicrobial activity dependent on two distinct colors of light.