Evolution of microbial biosensor based on functional RNA through fluorescence-activated cell sorting

Whole-cell microbial biosensors are emerging as tools for rapid, economic and on-site detection. A new approach to construct microbial biosensor with functional RNA for sensing of specific molecules is described here. The sensor is based on Spinach, an RNA mimic of GFP, and transcribed in living bacteria to detect intended molecules through fluorescent signals. Based on high-throughput cell cytometry, microbes with high selectivity and sensitivity could be screened out and evolved. Three microbial biosensors obtained through this method can efficiently detect tobramycin in different biosamples, providing a simple and economic solution for both qualitative and quantitative detection of antibiotics in the complex environments. This new strategy for the construction of whole-cell microbial biosensor and in vivo evolution protocol is especially suitable for any exogenous targets able to enter into bacteria and does not cause bacterial death in a short time, not just intracellular substances.