title: Biobar-coded gold nanoparticles and DNAzyme-based dual signal amplification strategy for ultrasensitive detection of protein by electrochemiluminescence.
abstract: A dual signal amplification strategy for electrochemiluminescence (ECL) aptasensor was designed based on biobar-coded gold nanoparticles (Au NPs) and DNAzyme. CdSeTe@ZnS quantum dots (QDs) were chosen as the ECL signal probes. To verify the proposed ultrasensitive ECL aptasensor for biomolecules, we detected thrombin (Tb) as a proof-of-principle analyte. The hairpin DNA designed for the recognition of protein consists of two parts: the sequences of catalytical 8-17 DNAzyme and thrombin aptamer. Only in the presence of thrombin could the hairpin DNA be opened, followed by a recycling cleavage of excess substrates by catalytic core of the DNAzyme to induce the first-step amplification. One part of the fragments was captured to open the capture DNA modified on the Au electrode, which further connected with the prepared biobar-coded Au NPs-CdSeTe@ZnS QDs to get the final dual-amplified ECL signal. The limit of detection for Tb was 0.28 fM with excellent selectivity, and this proposed method possessed good performance in real sample analysis. This design introduces the new concept of dual-signal amplification by a biobar-coded system and DNAzyme recycling into ECL determination, and it is promising to be extended to provide a highly sensitive platform for various target biomolecules.
authors.affiliation: College of Chemistry and §Analytical & Testing Center, Sichuan University , Chengdu, Sichuan 610064, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xia
authors.forename: Lingling
authors.initials: L
authors.lastname: Li
authors.forename: Zhouyang
authors.initials: Z
authors.lastname: Yin
authors.forename: Xiandeng
authors.initials: X
authors.lastname: Hou
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
mesh_terms: D015374:Biosensing Techniques; D019187:Cadmium Compounds / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D021881:DNA, Catalytic / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006801:Humans; D049449:Luminescence; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D009841:Oligonucleotides / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D045663:Quantum Dots; D015203:Reproducibility of Results; D018036:Selenium Compounds / Q000737:chemistry; D013917:Thrombin / Q000032:analysis*
chemical_list: D019187:Cadmium Compounds; D021881:DNA, Catalytic; D009841:Oligonucleotides; D011506:Proteins; D018036:Selenium Compounds; D006046:Gold; D004247:DNA; C058667:cadmium selenide; D013917:Thrombin
keywords: 8−17 DNAzyme; CdSeTe@ZnS QDs; biobar-coded Au NPs; dual signal amplification; electrochemiluminescence; protein