Calcium ion assisted fluorescence determination of microRNA-167 using carbon dots–labeled probe DNA and polydopamine-coated Fe3O4 nanoparticles

• Published in: Mikrochimica acta (1966) 2020-04, Vol.187 (4), p.212-212, Article 212
• Main Authors: Cao, Xiaodong, Zhang, Kairui, Yan, Wuwen, Xia, Zihao, He, Shudong, Xu, Xuan, Ye, Yongkang, Wei, Zhaojun, Liu, Songqin
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Biosensors; Calcium ions; Carbon dots; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Energy transfer; Fluorescence; Iron oxides; Magnetic separation; Microengineering; MicroRNAs; Nanochemistry; Nanoparticles; Nanotechnology; Original Paper; Ribonucleic acid; RNA
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-020-4209-8

A selective and sensitive fluorescence biosensor is described for determination of microRNA-167 using fluorescent resonant energy transfer (FRET) strategy. The FRET system comprises carbon dots (CDs, donor) labeled with probe DNA (pDNA) and polydopamine (PDA)-coated Fe 3 O 4 nanoparticles (Fe 3 O 4 @PDA NPs, acceptor). The CDs-pDNA can be absorbed onto the surface of Fe 3 O 4 @PDA NPs because of the strong π interaction between pDNA and PDA. With the enhanced adsorption ability of Fe 3 O 4 @PDA NPs by Ca 2+ , the fluorescence intensity of CDs at 445 nm (excitation at 360 nm) is quenched. In presence of microRNA-167, the hybridized complex of CDs-pDNA-microRNA-167 will be released from the surface of Fe 3 O 4 @PDA NPs due to the weak π interaction of the complex and PDA. This results in the fluorescence recovery of CDs. By application of twice-magnetic separation, the biosensor shows a wide linear range of 0.5–100 nM to microRNA-167 with a 76 pM detection limit. The method was applied to the determination of microRNA-167 in samples of total microRNA extractions from A. thaliana seedlings, and the recoveries ranged from 96.4 to 98.3%.