Fluorescent/colorimetric dual-mode for detecting of MC-LR using bidirectional RCA coupled with CdTe QDs.

A fluorescent/colorimetric dual-mode biosensor was designed using CdTe QDs and CRISPR/Cas for the efficient and ultrasensitive detection of microcystin-leucine-arginine (MC-LR). The biosensor mainly activates the trans-cleavage activity of Cas12a through nucleic acid amplification technology, such as bidirectional rolling circle amplification (B-RCA), to perform signal conversion, release Ag from the cleaving hairpin, quench QD fluorescence, and perform signal presentation. The biosensor can perform fluorometric and colorimetric detection, enabling rapid field assays.