1. Base amount-dependent fluorescence enhancement for the assay of vascular endothelial growth factor 165 in human serum using hairpin DNA-silver nanoclusters and oxidized carbon nanoparticles.
- Author
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Ji, Jiangrong, Xu, Xin, Chen, Panpan, Wu, Jiafeng, Jin, Yang, Zhang, Liying, and Du, Shuhu
- Abstract
A base amount-dependent fluorescence enhancement-based strategy is put forward to determine vascular endothelial growth factor 165 (VEGF
165 ) in human serum by the use of hairpin DNA-silver nanoclusters (hDNA-AgNCs) and oxidized carbon nanoparticles (CNPs). The hDNA-AgNCs aptasensing probe consists of AgNCs-contained hairpin loop (that generates a fluorescence signal), hairpin stem (that makes the structure stable), and the terminal aptamer 1 (that recognizes the target together with aptamer 2). It has been demonstrated that the fluorescence intensity of hDNA-AgNCs is ~ 3-fold stronger than that of single-stranded DNA-AgNCs (ssDNA-AgNCs), and hDNA-AgNCs have a strong dependence of fluorescence enhancement on the base amount in hairpin stem and loop. Upon the addition of oxidized CNPs, the terminal aptamer 1 of hDNA-AgNCs can adsorb onto the surface of oxidized CNPs via π-π stacking, and the fluorescence of hDNA-AgNCs (with excitation/emission maxima at 490/567 nm) is quenched via fluorescence resonance energy transfer (FRET). When aptamer 2 and VEGF165 are subsequently added, aptamer 1, VEGF165 , and aptamer 2 reassemble into an intact tertiary structure, and the fluorescence is recovered because hDNA-AgNCs are far away from the surface of oxidized CNPs and the FRET efficiency decreases. Under the optimized conditions, the aptasensing probe can selectively assay VEGF165 with a detection limit of 14 pM. The results provide a label-free and sensitive method to monitor VEGF165 in human serum. [ABSTRACT FROM AUTHOR]- Published
- 2020
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