When Nanoworlds Collide: Implementing DNA Amplification, Nanoparticles, Molecules, and FRET into a Single MicroRNA Biosensor

Isothermal nucleic acid amplification strategies have been combined with nanotechnology for advanced biosensing, material design, and biomedical applications. However, merging phenomena materials of different nanoscales the aim exploiting all their benefits at once has remained a challenging endeavor. Here, we exemplify various problems one can encounter when combining nanodimensions lanthanide complexes (?2 nm), Förster resonance energy transfer (FRET, ?5 quantum dots (QDs, ?20 rolling circle (RCA, ?250 nm) into single microRNA biosensor how these challenges be overcome. Six approaches, including simple FRET-RCA, enzyme-digesting FRET-hyperbranched-RCA were investigated. We demonstrated specific miR-21 detection 80 fM limit multiplexing capability FRET from Tb complex to QDs. The detailed view on multi-nanodimensional assay systems elucidated limited clinical translation such sophisticated multicomponent nanobiosensors.