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Published on: February 28, 2015
Novel Nucleic Acid-Assisted Ion-Responsive ECL Biosensor Based on Hollow AuAg Nanoboxes with Excellent SPR and
Jingxian Li1, Hongfen Yang2, Ren Cai1
1Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Material Science and Engineering, College of Chemistry and Chemical Engineering, College of Biology, Hunan University, Changsha 410082, China.
Abstract:
Novel hollow AuAg nanoboxes (AuAg NBs) were designed for an innovative electrochemiluminescence (ECL) sensor to ultrasensitively detect Pb2+ and Hg2+ with the aid of DNAzyme and "thymine-Hg2+-thymine" ("T-Hg2+-T") structure. AuAg NBs are employed as an excellent surface plasma resonance (SPR) source, as well as an effective coreaction accelerator for the CoNi NFs/S2O82- system to greatly improve ECL performance. To detect Pb2+, the DNAzyme catalyzes the cleavage of ribonucleic acid targets into numerous small nucleic acid fragments, leading to an ECL signal. When Hg2+ is added, the thymine-thymine (T-T) mismatches of the Hg2+ aptamer bind Hg2+ to form the "T-Hg2+-T" structure, which not only inhibits the SPR process but also produces a large steric hindrance, thus quenching the ECL signal and allowing quantification of Hg2+. The novel ECL sensor quantifies Pb2+ in the range of 0.1 fM to 0.1 μM with a limit of detection of 0.07 fM and Hg2+ in the range of 10 pM to 1 μM with a LOD of 4.07 pM.
