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 and materials of different nanoscales with the aim of exploiting all their benefits at once has remained a challenging endeavor. Here, we exemplify the various problems one can encounter when combining the nanodimensions of lanthanide complexes (similar to 2 nm), Forster resonance energy transfer (FRET, similar to 5 nm), quantum dots (QDs, similar to 20 nm), and rolling circle amplification (RCA, similar to 250 nm) into a single microRNA biosensor and how these challenges can be overcome. Six different approaches, including simple FRET-RCA, enzyme-digesting FRET-RCA, and FRET-hyperbranched-RCA were investigated. We demonstrated detection and multiplexing capability with FRET from a Tb complex to different QDs. The detailed view on the various complex multi-nanodimensional assay systems elucidated the limited clinical translation of such sophisticated multicomponent nanobiosensors.