Programmable bidirectional dynamic DNA nano-device for accurate and ultrasensitive fluorescent detection of trace...

Accurate and ultrasensitive detection of biomarkers is significance for the diagnosis of diseases at early stage. For this purpose, we herein develop a bidirectional dynamic DNA nano-device for amplified fluorescent detection of tumor marker of mucin 1 (MUC1). The nano-device is constructed by immobilizing two sets of DNA cascade catalytic probes on two opposite directions of a single-stranded DNA tracker to limit probe reactants to a compact space. Once target MUC1 binds to the aptamer sequence, the initiator DNA locked in the duplex DNA substrate can be released to induce DNA-initiated cascade hybridization reactions (DCHRs) simultaneously in two opposite directions along the tracker DNA, accompanying the displacement of two quencher labeled-DNA intermediate initiators to facilitate successively execution of DCHRs on the DNA nano-devices, which results in the separation of fluorophore (FAM) and quencher (Dabycl) to produce substantially recovered fluorescent signals for rapid and sensitive detection of MUC1 with a detection limit down to 0.18 pM. In addition, this strategy also exhibits high selectivity against other interfering proteins and potential application capacity in real serum samples, indicating its promising application prospects in disease diagnosis and treatment.