On-Particle Rolling Circle Amplification-Based Core-Satellite Magnetic Superstructures for MicroRNA Detection

Benefiting from the specially tailored properties of the building blocks as well as of the scaffolds, DNA-assembled core satellite superstructures have gained increasing interest-in drug delivery, imaging, and biosensing. The load of satellites plays,,a vital role in core satellite superstructures, and it determines the signal intensity in response to a biological/physical stimulation/actuation. Herein, for the first time, we utilize on-particle rolling circle amplification (RCA) to prepare rapidly responsive-core satellite magnetic superstructures With a high load of magnetic nanoparticle (MNP) Satellites. Combined with duplex-specific nuclease-assisted target recycling) the proposed magnetic superstructures hold great promise in sensitive and rapid microRNA detection. The long single-stranded DNA produced by RCA serving as the scaffold of the core satellite superstructure can be hydrolyzed by duplex-Specific nuclease in the presence of target microRNA, resulting in a release of MNPs that can be quantified in an optomagnetic sensor. The proposed biosensor has a-simple mix separate measure strategy. For let-7b detection, the proposed biosensor offers a wide linear detection range of approximately 5 orders of magnitude with a detection sensitivity of 1 fM. Moreover, it has the capability to discriminate single-nucleotide mismatches and to detect let-7b in cell extracts and serum, thus showing considerable potential for clinical applications.