A sensitive fluorescence assay based on aggregation-induced emission by copper-free click reaction for rapid ctDNA detection

A fluorescence assay was developed based on aggregation-induced emission for circulating tumor (ctDNA) rapid detection. AIE-based probe (TPE-DNA) was constructed via strain-promoted azide-alkyne cycloaddition reaction between the azide-functionalized TPE-N3 and the dibenzocyclooctyne functionalized DNA. AIE-based assay displayed significant fluorescence signal enhancement for the ctDNA targets. The experimental results were verified and explained based on density functional theory simulations. As a proof-of-concept, the ctDNA as the target was detected to determine the feasibility of the assay. The detection could be done within 10 min with the limit of detection of 39 pM and good selectivity without the assistance of enzyme or nano-materials. Compared with traditional click reaction, the assay has advantages of high efficiency and good biocompatibility. It is promising in rapid diagnostic of cancer marker nucleic acid with further efforts to develop intelligent miniaturized equipment.