A highly sensitive electrochemical IFN-γ aptasensor based on a hierarchical graphene/AuNPs electrode interface with a dual enzyme-assisted amplification strategy. Issue 71 (21st September 2017)

• Record Type: Journal Article
• Authors: Yin, Yu; Shi, Lei; Chu, Zhenyu; Jin, Wanqin
• Is Part Of: RSC advances. Volume 7:Issue 71(2017)
• Page Start: 45053
• Page End: 45060
• Publication Date: 2017-09-21
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra07817j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A new signal-on electrochemical aptasensor for IFN-γ assay is constructed on a hierarchical graphene/AuNPs modified electrode coupled with a dual enzyme-assisted signal amplification strategy. Abstract : In this work, we have developed a new electrochemical aptasensor for IFN-γ assay, based on a hierarchical graphene/AuNPs modified electrode coupled with a dual enzyme-assisted signal amplification strategy. The graphene/AuNPs modified electrode with a large specific area, high conductivity, excellent stability and biocompatibility was used for the immobilization of plentiful duplex DNA strands of capture probes and IFN-γ aptamers. In the presence of IFN-γ, hybridized aptamers were released from the electrode surface due to the formation of aptamer/IFN-γ complexes. Meanwhile, aptamers were digested with RecJf exonuclease and IFN-γ was available for target recycling, creating numerous free capture probes on the electrode surface. Then the hybridization chain reaction was initiated with the help of linker probes and biotin-labeled reporter probes. Thus cascade duplex DNA polymers were produced on the electrode surface, providing lots of binding sites for streptavidin–alkaline phosphatase to generate robust enzyme-catalyzed signals. Due to this dual enzyme-assisted amplification strategy, the prepared aptasensor exhibited a wide linear range from 5 pM–5 nM with an ultralow detection limit of 2 pM (S/N = 3). Besides, the aptasensor showed an excellent selectivity, satisfactory reproducibility and stability, and a great potential in serum analysis. Importantly, the versatility of the designed sensing strategy makes it easily extended for analyzing other biomolecules.