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

• DOI: 10.1021/acsami.7b16293
• Publication Date: 2017-12-21T19:25:50Z
• Authors: Bo Tian; Zhen Qiu; Jing Ma; Marco Donolato; Mikkel Fougt Hansen; Peter Svedlindh; Mattias Strömberg
• Keywords: Optomagnetic biosensor; Biosensing Techniques; DNA; 01 natural sciences; Core−satellite superstructures; 0104 chemical sciences; Magnetics; MicroRNAs; Magnetic nanoparticles; On-particle rolling circle amplification; Nucleic Acid Amplification Techniques; 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.