A signal-on ratiometric fluorometric heparin assay based on the direct interaction between amino-modified carbon dots and DNA

• Published in: Mikrochimica acta (1966) Vol. 185; no. 5; pp. 260 - 9
• Main Authors: Huang, Jianyong, Li, Fenglan, Guo, Rubin, Chen, Yuyuan, Wang, Zhenzhen, Zhao, Chengfei, Zheng, Yanjie, Weng, Shaohuang, Lin, Xinhua
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.05.2018; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Anticoagulants; Carbon dots; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Deoxyribonucleic acid; DNA; Fluorescence; Genetic research; Microengineering; Nanochemistry; Nanotechnology; Original Paper; Recovery; Fluorescent carbon nanomaterial; Ratiometric strategy; Sensitive detection; Fluorescence assay; ssDNA quenching platform
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-018-2798-2

Amino-modified carbon dots (C-dots) with positively charged surface were prepared. They display strong blue fluorescence and are shown to act as quenchers of the green fluorescence of FAM-labeled ssDNA such as the F-probe used in this work that was immobilized on the C-dots. On the addition of highly negatively charged heparin (Hep), it will interact with the C-dots and displace the F-probe from C-dots. Once the F-probe is displaced by Hep, its green fluorescence is restored. The intrinsic blue fluorescence of the C-dots remains stable after addition of Hep. Thus, a signal-on ratiometric fluorometric assay was developed for the ultra-sensitive detection of Hep. The underlying mechanisms of quenching and recovery are discussed. Under optimized conditions, the recovery of the ratiometric fluorescence of the system composed of C-dots and quenched F-probe is proportional to the Hep concentration in the range of 0.01–2.0 μg·mL −1 (= 0.00125–0.25 U·mL −1 ). The method was successfully applied to the determination of Hep in spiked serum samples. Graphical abstract Schematic of a signal-on ratiometric fluorometric method for the ultra-sensitive detection of heparin on the basis of the displacement and fluorescence enhancement of adsorbed FAM-labeled ssDNA from amino-modified carbon dots (C-dots) by heparin.