Authors
Jiaxun Zhang, Shijin Zhou, Jinming Kong, Xueji Zhang
Published in
Analytical methods : advancing methods and applications. Oct 13, 2026. Epub Oct 13, 2026.
Abstract
The ultrasensitive detection of microRNAs in bodily fluids is crucial for early diagnosis of cancer. Herein, we design an electrochemical biosensor based on a dual-signal amplification strategy utilizing reversible addition-fragmentation chain transfer (RAFT) and ring-opening metathesis polymerization (ROMP) to achieve ultra-sensitive quantitative detection of miRNA-21. The sensing interface starts from a gold electrode carrying a thiol-immobilized peptide nucleic acid (PNA) capture probe. Once miRNA-21 hybridizes specifically with the PNA, we anchor the RAFT chain-transfer agent 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (CDTPA) onto the duplex by taking advantage of Zr4+ coordination chemistry. With the azo initiator 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (VA-044), in solution, the monomer dicyclopentenyloxyethyl acrylate (DCPEA)-which bears a cyclopentene side group-undergoes RAFT polymerization, decorating the duplex with polymer chains that bristle with pendant cyclopentene rings. Subsequently, the ruthenium-based catalyst AquaMet ((4-((4-ethyl-4-methylpiperazin-1-ium-1-yl)methyl)-1,3-dimesitylimidazolidin-2-ylidene)dichloro(2-isopropoxybenzylidene) ruthenium(II)) chloride coordinates with the cyclopentene groups, catalyzing the ROMP of cyclopentene-based ferrocene (CFc), thereby forming a polymer brush rich in ferrocene electroactive molecules on the electrode surface, achieving efficient two-stage amplification of the electrochemical signal. Under optimized conditions, the sensor returns a linear response to miRNA-21 from 10-17 M to 10-13 M and reaches a detection limit as low as 4.72 aM. Signals from single-mismatched RNA, triple-mismatched RNA, and miRNA-320b were all strongly suppressed relative to the target, while the sensor also proved to be stable in one week and remarkably unfazed by complex biological backgrounds.
PMID:
42865097
Bibliographic data and abstract were imported from PubMed on 13 Oct 2026.
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