Evolution on a Microscale: Empowering Adaptation and Selection through a Microfluidic Chip

Background: Adaptive laboratory evolution (ALE) is a key tool for studying fundamental evolutionary processes and a widely used methodology for generating novel, optimized traits for bioproduction. Microfluidics have revolutionized microbial ALE as it can mimic naturally occurring microenvironments promoting the growth of biofilms alongside planktonic cells.

Objective: The aim was to develop a user-friendly and cost-effective microfluidic chip device to perform miniaturized, automated ALE experiments.

Method: The microfluidic evo.S (evolution under stress) chip was designed to create tuneable and spatially stable stressor concentration gradients across interconnected growth wells to adapt microbial cells to stressors such as antibiotics.

Results: The cultivation of microbial cells in the growth wells creates microenvironments within the chip, resulting in mixed populations, ranging from planktonic cells over to stiff biofilms. The chip was successfully used to adapt Escherichia coli to different antibiotics and revealed its ability to differentiate between persistence and resistance. Importantly, this approach led to the discovery of previously unknown mutations that confer resistance to nalidixic acid. ... mehrRecently, a customized chip setup was used to successfully adapt the thermophilic organism Thermus thermophilus to kanamycin and to the utilization of an alternative carbon source.

Conclusion: The evo.S chip enhances the occurrence of mutations, resulting in the generation of stress-resistant strains. This kind of chip-based ALE can be applied to adapt virtually any microorganism to desired environmental conditions and offers crucial insights into the mechanism of antibiotic resistance and biofilm formation.