Fig. 3. Biosensor responsive compounds. Dose response curves for the different compounds using the P_LC biosensor system in E. coli BL21 and their respective molecular structures. The fluorescent gene expression normalised to cell density (RFU/OD₆₀₀) was expressed relative to the P_LC biosensor response curve with ferulic acid. Five compounds (1–5) generated high levels of expression with efficacy superior to 70% (A). Eight compounds generated moderate levels of expression with efficacies ranging from 10% to 55% (6–13) (B). * Compound numbers with respective names are described in Table 2 and Table S3 (ESI†).