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Antibiotics are a key control mechanism for synthetic biology and microbiology. Resistance genes are used to select desired cells and regulate bacterial populations, however their use to-date has been largely static. Precise spatiotemporal control of antibiotic resistance could enable a wide variety of applications that require dynamic control of susceptibility and survival. Here, we use light-inducible Cre recombinase to activate expression of drug resistance genes in Escherichia coli. We demonstrate light-activated resistance to four antibiotics: carbenicillin, kanamycin, chloramphenicol, and tetracycline. Cells exposed to 465 nm blue light survive in the presence of lethal antibiotic concentrations, while those kept in the dark do not. To optimize resistance induction ranges, we characterize the impact of the promoter, ribosome binding site, and enzyme variant strength using chromosome and plasmid-based constructs. Using time-lapse microscopy, we further show resistance activation dynamics. These optogenetic drug resistance tools pave the way for spatiotemporal control of cell survival. |
