2D hexagonal SnS2 nanoplates as novel co-reaction accelerator for construction of ultrasensitive g-C3N4-based electrochemiluminescent biosensor

Abstract

In this work, a highly luminous efficiency methotrexate (MTX) biosensor was successfully prepared with the introduced of SnS2 nanoplates as novel co-reaction accelerator towards amplification electrochemiluminescence (ECL) signal of graphite-like carbon nitride/peroxidisulfate (g-C3N4/K2S2O8) system. Specifically, the SnS2 nanoplates, as an electrochemically regenerable co-reaction accelerator, could accelerate the reduction of S2O82− to produce abundant of sulfate-free radical (SO4·−), evidently enhancing the ECL emitting of g-C3N4. Owing to the reversible electrochemical process of Sn2+ and Sn4+, the regenerable of Sn4+ reactive sites could occur at the surface of electrode, significantly improving the efficiency of co-reaction accelerator. Based upon the excellent quenching effect of MTX towards g-C3N4/K2S2O8 system, the fabricated ECL biosensor manifested high sensitivity with a detection limit of 0.27 pM in the concentration of MTX from 1 pM to 10 μM. More importantly, the constructed biosensor was successfully applied to quantitation of MTX in human serum with favorable results. Consequently, the proposed strategy provided a new sight in the trace determination of MTX in bioanalysis fields.