Ratiometric antifouling electrochemiluminescence biosensor based on bifunctional peptides and low toxic quantum dots

Key Words:ULTRASENSITIVE DETECTION; GRAPHENE; ELECTROCHEMISTRY; THROMBIN; DNA; IMMUNOASSAY; APTASENSOR; MARKERS; GROWTH; SENSOR

Abstract:It is a great challenge to detect the target selectively and accurately in complex biological samples. A ratiometric signal amplification strategy based on antifouling peptide is proposed to detect thrombin (TB) in this work. The electrode is modified with conducing polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and Au@Luminol. Then the bi-functional peptide anchors to the modified electrode and captures the low toxic electrochemiluminescence (ECL) probe. The bi-functional peptide includes a new antifouling sequence (DRDRDRDR) and a TB recognizable sequence (SGRPVLG), while the former can greatly reduce the non-specific adsorption in complex samples and the latter can be cleaved by TB. The new self-enhanced luminescence probe labeled as PAMAM-QDs is composed of low toxic and water-soluble CuInZnS/ZnS quantum dots (CIZS/ZnS QDs) and polyamidoamine (PAMAM) via amide bonds. Concentration of TB can be obtained via the ratio of the signals of ECLQDs/ECLAu@Luminol accurately and sensitively. The ECL biosensor with the detection line 1.82 fM can work from 10 fM to 1 nM. Thanks to the antifouling property of the designed peptide and the amplification of the new ECL probe, the biosensor can be used for quantifying TB in practical complex samples with high selectivity and sensitivity.

Volume:322

Translation or Not:no