LAUSR

In clinical diagnosis field, it is important to construct potential-resolved multiplex electrochemiluminescence (ECL) biosensor for decreasing false-positive rate and improving the diagnosis's accuracy. However, the shortage of low-potential cathodic luminophores between -1 and 0 V(vs. Ag/AgCl) severely limited its development. Herein, we synthetised a novel luminophore N,N-bis-(3-dimethyl aminopropyl)-3,4,9,10-perylene tetracarboxylic acid diimide(PDI) which gave dual emissions at -0.25/-0.26 V with K2S2O8 as coreactant in aqueous solution. The ECL was assigned to excitated J-type PDI dimers. Then PDI and luminol were used as luminophores to respectively combine with graphite oxide(GO) and gold nanoparticles(AuNPs) and form potential-resolved ECL nanoprobes. And this potential-resolved ECL nanoprobes were respectively functionalized by secondary antibodies(Ab2) to construct a low-potential sandwiched ECL immunosensor for tumor markers carcinoembryonic antigen(CEA) and α-fetoprotein (AFP) simultaneous determination during linear scanning potential range from -0.6 to 0.6 V. The prepared multiplex immunosensor exhibited sensitive ECL response for CEA at -0.6 V due to PDI and AFP at 0.6 V due to luminol and both linear semilogarithmical ranges were from 0.1 pg ml-1 to 1 ng mL-1. In addition, PDI with dual ECL peaks showed enticing prospect of built-in self-calibration for a precise quantitative and bio-imaging analysis.