Fig. 2

Overview of the use of biosensors in CFS. The general workflow usually involves in silico design of gene circuits encoding biosensors and reporter proteins, followed by chemical synthesis of such circuits. Meanwhile, patient or environmental samples are collected, target analytes are extracted, and, in some cases, amplified. The gene circuits and target analytes are then added to CFS. Examples of biosensors in CFS have included a) mercury (II) detection using the MerR repressor[45], b) viral and bacterial nucleic acid sensing using toehold switch-based sensors [46, 50, 59], c) identification of P. aeruginosa infection by its quorum sensing molecule, 3-oxo-C12-HSL, using the LasRV sensor [61] and d) recognition of an endocrine-disrupting compound by utilizing an allosterically activated fusion protein containing the ligand binding domain of a human estrogen receptor [62, 63]. Reporters (e.g., colorimetric or fluorescent) can then produced, contingent upon analyte detection, enabling clinical diagnosis (e.g., using standard spectrophotometers)