Synthetic cell-based biosensors and methods for discovering novel sensing elements

With the advancement of synthetic biology, cells can be modified and engineered through gene recombination, gene editing and protein engineering. Given that many elements in gene expression are environmental-sensitive, synthetic biosensor based on cells has been proposed and many studies have validated this concept. Synthetic biosensors can facilitate research on the revelation of biomolecular activity in living systems. And it has the advantages of easy operation, energy economy, and adaptability. This review introduces three types of synthetic biosensors including transcriptional biosensors, translational biosensors, and post-translational biosensors. Then the topic will focus on approaches that help discovery of biosensing elements in cells, which is vital but still challenging for the development of synthetic biosensors. Cell-free assays, directed revolution, high through-put screening and computational methods are discussed in this review. Subsequently, the application of synthetic biosensors is summarized, presenting utility and advantages of them. At last, the future direction is discussed, hoping to provide prospects or advice for research in this field.