Recent advances in synthetic biology-enabled and natural whole-cell optical biosensing of heavy metals

A large number of scientific works have been published on whole-cell heavy metal biosensing based on optical transduction. The advances in the application of biotechnological tools not only have continuously improved the sensitivity, selectivity, and detection range for biosensors but also have simultaneously unveiled new challenges and restrictions for further improvements. This review highlights selected aspects of whole-cell biosensing of heavy metals using optical transducers. We have focused on the progress in genetic modulation in regulatory and reporter modules of recombinant plasmids that has enabled improvement of biosensor performance. Simultaneously, an attempt has been made to present newer platforms such as microfluidics that have generated promising results and might give a new turn to the optical biosensing field.