3,4,9,10-Perylenetetracarboxylic dianhydride functionalized graphene sheet as labels for ultrasensitive electrochemiluminescent detection of thrombin

A novel tracer, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) functionalized graphene sheet (GS) composite (GS–TCDA), is employed to label the secondary anti-thrombin aptamer (TBA) to construct an ultrasensitive electrochemiluminescent sandwich-type aptasensor. The GS provided large surface area for loading abundant PTCDA and TBA with good stability and biocompatibility. Because of the excellent electroconductivity of GS and the desirable optical properties of PTCDA, the as-formed Apt II bioconjugate considerably amplified the electrochmiluminescence (ECL) signal of peroxydisulfate (S2O82−) and worked as the desirable label for Apt II. On the basis of the considerably amplified ECL signal and sandwich format, an extremely wide range from 1 fM to 1 nM with an ultralow detection limit of 0.33 fM for thrombin was obtained. Additionally, the selectivity and stability of the proposed aptasensor were also excellent. Thus, this procedure has great promise for detection of thrombin present at ultra-trace levels during early stage of diseases.

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► We constructed a novel sandwich-type ECL aptasensor with 3,4,9,10-perylenetetracarboxylic dianhydride functionalized graphene sheet composite (GS–TCDA) for secondary anti-thrombin aptamer (TBA 2) labeling.
► The GS provided large surface area for loading abundant PTCDA and TBA 2 with good stability and biocompatibility.
► The as-formed GS–TCDA–TBA 2 bioconjugates were captured onto the electrode surface via “sandwich” reaction, obtaining a considerably enhanced ECL signal due to the synergistic amplification of PTCDA and GS on the ECL intensity of S2O82−.
► To the best of our knowledge, synergistic amplification of PTCDA and GS on the ECL signal of S2O82− was first reported here to develop a sensitive aptasensor.