Self-assembly of nucleic acid molecular aggregates catalyzed by a triple-helix probe for miRNA detection and single cell imaging

We herein report a novel finding that nucleic acid molecular aggregates (NAMAs) self-assembled on graphene oxide nanoplates (GONPs) as a result of DNA rolling circle amplification (RCA) and a functionalized triple-helix probe (THP) in single cells. The functionalized THP containing the aptamer region for target recognition and the trigger DNA region for RCA was firstly used to activate RCA for miRNA imaging in single cells. Interestingly, NAMAs with the fluorescent labels were hybridized by both the RCA products and FAM-DNA, and could partly self-assemble on GONPs; meanwhile, NAMAs could extend from the GONPs, which led to the quenched fluorescence being renewed. Significantly, the NAMAs were successfully applied for low-abundance miRNA detection and imaging in single cells. The self-assembled NAMAs could generate prominent and agminated fluorescence-bright spots in single cancer cells, which will effectively drive cell imaging into a new era.