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In this paper, we report a highly sensitive chemiluminescence(CL) sensor for Hg2+ ions based on thymine-Hg2+-thymine(T-Hg2+-T) coordination chemistry. We designed a thymine rich oligonucleotide as a capture probe and a signal probe that includes two functional domains: a horseradish peroxidase-mimicking DNAzyme domain for the generation of CL, and a recognition domain. Graphene oxide(GO) was introduced to adsorb the signal probe via π-π interaction, which brought the DNAzyme domain and GO into close proximity and quenches CL. In the presence of Hg2+ ions, the coordination of Hg2+ with the capture probe yielded a hairpin complex, triggers cascaded strand displacement reactions and Exonuclease III-assisted signal amplifications. As a result, accumulated amounts of DNAzyme were generated and released from GO, leading to an enhanced CL signal. This strategy combines enzyme-based signal amplification and GO as a background reducer, leads to a limit of detection(LOD) of 2 nmol/L. This simple detection system provides a label-free yet sensitive approach for detection of Hg2+ ions.
In this paper, we report a highly sensitive chemiluminescence (CL) sensor for Hg2 + ions based on thymine-Hg2 + -thymine (T-Hg2 + -T) coordination chemistry. We designed a thymine rich oligonucleotide as a capture probe and a signal probe that includes Two functional domains: a horseradish peroxidase-mimicking DNAzyme domain for the generation of CL, and a recognition domain. Graphene oxide (GO) was introduced to adsorb the signal probe via π-π interaction, which brings the DNAzyme domain and GO into close proximity and quenches CL. In the presence of Hg2 + ions, the coordination of Hg2 + with the capture probe yielded a hairpin complex, triggers cascaded strand displacement reactions and Exonuclease III-assisted signal amplifications. As a result, accumulated amounts of DNAzyme were generated and released from GO, leading to an enhanced CL signal. This strategy combines enzyme-based signal amplification and GO as a background reducer, leads to a limit of detection (LOD) of 2 nmol / L. This simp le detection system provides a label-free yet sensitive approach for detection of Hg2 + ions.