Synthetic biology has promoted the development of biosensors as tools
for detecting trace substances. In the past, biosensors based on
synthetic biology have been designed on living cells, but the
development of cell biosensors has been greatly limited by defects such
as the obstruction of cell membrane. However, the advent of cell-free
synthetic biology addresses these limitations. Biosensors based on the
cell-free protein synthesis system have the advantages of higher safety,
higher sensitivity, and faster response time over cell biosensors, which
makes cell-free biosensors have a broader application prospect. This
review summarizes the workflow of various cell-free biosensors,
including the identification of analytes and signal output. The
detection range of cell-free biosensors is greatly enlarged by different
recognition mechanisms and output methods. In addition, the review also
discusses the applications of cell-free biosensors in environmental
monitoring and health diagnosis, as well as existing deficiencies and
aspects that should be improved. In the future, through continuous
improvement and optimization, the potential of cell-free biosensors will
be stimulated, and their application fields will be expanded.