Highly selective and sensitive colorimetric and fluorescence detection of copper(II) and glyphosate using dual-functional peptide probe and its multifarious applications in food sample analysis and bioimaging.

A novel dual-functional probe FSH from dipeptide (Ser-His-NH) and 5-carboxy fluorescein (5-FAM) fluorophore was developed for the relay detection of copper ions (Cu) and glyphosate (Glyp). As design, FSH exhibited high selectivity to Cu using colorimetric and fluorimetric methods, and formed non-fluorescence FSH-Cu ensemble. Further, the FSH-Cu ensemble responded to glyphosate with notable selectivity through fluorescence enhancement effect and colorimetric changes. The limit of detections (LODs) for Cu and glyphosate were calculated as 40.4 nM and 15.9 nM, respectively. Notably, FSH was successfully applied to the continuous detection and imaging of Cu and glyphosate in real water samples, test strips, living cells and zebrafish larvae. Moreover, we constructed the molecular logic gate for high sensitivity analysis, and the applications of FSH for "naked-eye" monitoring in food, plants and soil. More importantly, a portable smartphone-assisted RGB analysis method was designed to allow semi-quantitative detection of Cu and glyphosate.