Recent progress in strategies for the creation of protein-based fluorescent biosensors

The creation of novel bioanalytical tools for the detection and monitoring of a range of important target substances and biological events in vivo and in vitro is a great challenge in chemical biology and biotechnology. Protein-based fluorescent biosensors--integrated devices that convert a molecular-recognition event to a fluorescent signal--have recently emerged as a powerful tool. As the recognition units various proteins that can specifically recognize and bind a variety of molecules of biological significance with high affinity are employed. For the transducer, fluorescent proteins, such as green fluorescent protein (GFP) or synthetic fluorophores, are mostly adopted. Recent progress in protein engineering and organic synthesis allows us to manipulate proteins genetically and/or chemically, and a library of such protein scaffolds has been significantly expanded by genome projects. In this review, we briefly describe the recent progress of protein-based fluorescent biosensors on the basis of their platform and construction strategy, which are primarily divided into the genetically encoded fluorescent biosensors and chemically constructed biosensors.