The goal of engineering living matter is to modify biological attributes to leverage the unique capabilities of living organisms. One prevalent method involves rendering living matter responsive to specific stimuli through either synthetic biology techniques or functional materials, aiming to modulate the electrophysiology and activity of cells and organisms. This method applies to bacteria as well, despite the fact that the connections between their electrophysiology, bioelectricity, bioenergetics, and behavior have only recently started to be elucidated. Recent studies have revealed that bacterial membrane potential is a dynamic, rather than static, parameter and plays a significant bioelectric signaling role. Such a communication paradigm governs their metabolism, behavior, and functions within microbial communities. Given that membrane potential dynamics mediate this language, manipulating this parameter represents a promising and intriguing strategy for bacterial engineering.

Here, I show that precise optical modulation of bacterial membrane potential can be achieved through a materials-based approach. Specifically, we found that the isomerization reaction at the membrane location induces either hyperpolarisation or depolarisation of the potential depending on the excited state deactivation pathways, within a bio-mimetic mechanism reproducing the initial fate of retinal. This can trigger neuron-like bioelectric signaling and can highlight the role of previously uncharacterized ion channels in bacteria electrophysiology. Finally, I also show perspectives on the light-modulation of antibiotic uptake, as well as on the photocontrol of bacterial motion and assembly behavior in consortia and multispecies ecosystems