Construction of efficient "on-off-on" fluorescence aptasensor for ultrasensitive detection of prostate specific antigen via covalent energy transfer between g-C3N4 quantum dots and palladium triangular plates

Key Words:SENSITIVE DETECTION; ELECTROCHEMICAL IMMUNOSENSOR; GRAPHENE; AGGREGATION; IMMUNOASSAY; NANOSHEETS; APTAMERS; PLATFORM; PROBES; FACILE

Abstract:Development of ultra-sensitive and high specific aptasensors is important for early diagnosis of prostate cancer. Herein, ultrasensitive detection of prostate specific antigen (PSA) aptasensor was realized based on the "on-off-on" model via fluorescence (FL) covalent energy transfer between g-C3N4 quantum dot (g-CNQDs) and palladium triangular plates (Pd TPs). Specifically, the Pd TPs were primarily linked with PSA aptamer (PA) as the reporter probe, followed by attaching them onto the g-CNQDs surfaces, causing the highly enlarged FL quenching rate (ca. 75%). After the introduction of PSA, the FL intensities recovered again because of the distinctively stronger affinity of PA to PSA than that of g-CNQDs. The bond of pyridine N with Pd was identified as efficient energy transfer pathway through the X-ray photoelectron spectroscopy (XPS) and FL measurements. The surface plasmon resonance (SPR) experiments certified the remarkably different affinity of PA towards g-CNQDs and PSA. The as-constructed FL aptasensor can accurately quantify PSA with wide linear range of 10 pg mL(-1)-50 ng mL(-1) and ultra-low limit of detection (LOD, 4.2 pg mL(-1)), indicating the promising applications in clinical assay and biological detection. (C) 2020 Elsevier B.V. All rights reserved.

Volume:1104

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Translation or Not:no