RESUMO
Based on target cycling amplification and 3 ,4 ,9 ,10-perylenetetracarboxylic dianhydride derivative functionalized singal probe, an ultrasensitive electrochemiluminescence ( ECL) sensor was designed for the detection of lead ions. The hairpin substrate DNA was immobilized on the electrode through molecular self-assembly. In the presence of Pb2+and DNAzyme, the substrate was cleaved with single strand DNA fragments left on the electrode surface. Meanwhile, the target and DNAzyme was released for another cleaving circularly. As a result, the single strand DNA fragments hybridized with the assist hairpin probe H1, which leaded to the fabrication of H2 labeled with the 3 , 4 , 9 , 10-perylenetetracarboxylic dianhydride derivative functionalized hollow gold nanoparticles. With the increasing concentration of Pb2+, much more signal probe was been captured and the ECL signal of the biosensor in peroxydisulfate ( S2 O2-8 ) solution would increase. An ECL assay demonstrates that the sensor has a good linear response to Pb2+ concentration in the range of 1í10-12 mol/L-1í10-6 mol/L, with a detection limit of 1í10-12 mol/L. The fabricated sensor shows good selectivity toward Pb2+against other common metal ions.