Integrating high mannose-binding aptamer and CRISPR/Cas12a machinery for the remote detection of cell surface high mannose

High mannose is overexpressed on the cell surface during carcinogenesis; however, there are currently no efficient techniques for its detection. Herein, we propose an assay called RADAR ( r emote high m a nnose d etection on cell surf a ce with C R ISPR) for the quantification of high mannose, leveraging the integration of high mannose-binding aptamer and CRISPR technique. The high mannose-binding aptamer is hybridized with a locker, which is released upon specific binding to high mannose. The released locker then activates CRISPR/Cas12a to produce a fluorescence signal. The "remote" concept in RADAR refers to the recognition of high mannose occurring on the cell surface, while signal generation takes place in a solution separate from the target. This feature makes RADAR suitable for the detection of suspended bio-samples without the need for sophisticated imaging. RADAR can detect high mannose Man 9 with a limit of detection of 2.5 nM, distinguish cancer cells from non-cancerous cells, and profile high mannose level in human serum for potential non-small cell lung cancer (NSCLC) diagnosis. This work represents the first attempt to integrate CRISPR technology into the aptasensing of high mannose, which may serve as a synthetic biology-enabled tool in glycochemistry and glycobiology.