Enzyme-free amplified detection of cellular microRNA by light-harvesting fluorescent nanoparticle probes

Detection of cellular microRNA biomarkers is an emerging powerful tool in cancer diagnostics. Currently, it requires multistep tedious protocols based on molecular amplification the RNA target, e.g. RT-qPCR. Here, we developed a one-step enzyme-free method for detection extracts light-harvesting nanoparticle (nanoantenna) biosensors. They amplify fluorescence signal by effective Förster resonance energy transfer (FRET) from ultrabright dye-loaded polymeric to single acceptor and thus convert recognition one copy (through nucleic acid strand displacement) into response >400 dyes. The nanoprobes 17–19 nm diameter four microRNAs (miR-21, let-7f, miR-222 miR-30a) exhibit outstanding brightness (up 3.8 × 107 M?1cm?1) ratiometric sequence-specific with limit (LOD) down 1.3 pM (21 amol), equivalent 24 RT-qPCR cycles. enable quantitative five cancerous cell lines (human breast - T47D MCF7, head neck CAL33 glioblastoma LNZ308 U373) two non-cancerous ones (Hek293 MCF10A), agreement results confirmed that let-7f especially miR-21 are systematically overexpressed all studied lines. These biosensors compatible low-cost portable fluorometers small volumes (11 amol LOD), opening route rapid point-of-care