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

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 VEGF 165 are subsequently added, aptamer 1, VEGF 165 , 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 VEGF 165 with a detection limit of 14 pM. The results provide a label-free and sensitive method to monitor VEGF 165 in human serum.

Aptamers Versus Vascular Endothelial Growth Factor (VEGF): A New Battle against Ovarian Cancer

“…The aptasensing probe has a detection limit of 14 pM and can only assess VEGF165 under optimal conditions. Discovery provides a sensitive, label-free method to detect VEGF165 in human serum using a DNA aptamer [ 115 ].…”

“…Aptamers and nanomaterials work together to increase the rate of early VEGF detection and the effectiveness of targeted ovarian cancer therapy [18]. Alkalinity-dependent fluorescence enhancement-based treatment High sensitivity and selectivity Significant cytotoxicity and improved anti-tumor efficiency [114] Colorimetric assay High sensitivity Lower detection limit [115] Sandwich-type colorimetric microplate detector Quick and easy detection of VEGF in blood Higher anti-tumor efficiency [116] Aptamer-based technologies remain in their infancy, and further study is required to guarantee their general acceptance. Despite several clinical studies, aptamer therapeutic uses have been sluggish to gain popularity.…”