For example, resistance is often spread through horizontal gene transfer events 11, 12, which are difficult to monitor and control at the single-cell level. Spatiotemporal control over drug resistance could enable spatial patterning in living biomaterials 7, selection of single cells from microfluidic systems 8, 9, and improved understanding of the role dynamics play in clinical antibiotic resistance 10. 4 developed an inducible origin of replication-another ubiquitous feature within synthetic biology constructs-it sparked new areas of research including biological data storage 5 and whole-cell riboswitch diagnostics 6. The ability to control drug resistance spatially and temporally could open new avenues for synthetic biology research. Examples include chromosomal insertions, where expression of resistance genes can be used as a selective marker for successful integration 1, or in the creation of transposon libraries, where drug resistance is used as an intermediate selection mechanism before being swapped for an alternative sequence 2, 3.Īlthough antibiotic resistance genes are a staple of synthetic biology and microbial biotechnology research, there are few methods for dynamic control of their expression. Resistance genes also play an important role in cloning methods. They are included in genetic constructs to ensure plasmid propagation. These optogenetic resistance tools pave the way for spatiotemporal control of cell survival.Īntibiotic resistance genes are widely used in synthetic biology. We then link inducible resistance to expression of a heterologous fatty acid enzyme to increase production of octanoic acid. To optimize resistance induction, we vary promoter, ribosome binding site, and enzyme variant strength using chromosome and plasmid-based constructs. Cells exposed to blue light survive in the presence of lethal antibiotic concentrations, while those kept in the dark do not. We demonstrate light-activated resistance to four antibiotics: carbenicillin, kanamycin, chloramphenicol, and tetracycline.

Here, we use light-inducible Cre recombinase to activate expression of drug resistance genes in Escherichia coli. Precise spatiotemporal control of antibiotic resistance could enable a wide variety of applications that require dynamic control of susceptibility and survival. Resistance genes are used to select desired cells and regulate bacterial populations, however their use to-date has been largely static. Antibiotics are a key control mechanism for synthetic biology and microbiology.

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