Abstract
Stratifin (SFN) is considered to be a new biomarker of cancers. In clinical medicine, combining tissue chip technology and immunohistochemical methods qualitatively prove that the abnormal expression of SFN is related to cancer. However, the quantitative detection of SFN is rarely performed. Herein, an ultrasensitive ratiometric ECL immunosensor was constructed to realize SFN determination. A polyvinylpyrrolidone (PVP)-assisted synthesis of TiO2 (PVP-TiO2)@Poly[(9,9-dioctyfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadia-zol-4,8-diyl)] (PFBT) nanomaterial with anodic ECL signal and carbon-coated TiO2 (C-TiO2)-loaded graphitic carbon nitride quantum dots (g-C3N4 QDs) with cathodic ECL signal were firstly used as a pair of luminophores to generate two potential-resolved ECL signals. PVP-TiO2 provided a substrate for the immobilization of biomolecules. C-TiO2 due to the high specific surface area loaded a large amount of g-C3N4 QDs, thereby increasing the ECL intensity. Not only that, the heterojunction formed by semiconductors could also further enhance ECL signal. Impressively, PFBT-C-TiO2 conjugation possessed outstanding photothermal property, which could serve as photothermal convertor device and accelerate the electrochemical mass transfer on the electrode surface, further amplified ECL signal. The ratiometric biosensor showed good linear response for SFN from 10−6ng mL–1 to 0.1 ng mL–1 with a detection limit of 0.33 fg mL–1.
Published Version
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