title: G-quadruplex DNAzyme-based electrochemiluminescence biosensing strategy for VEGF165 detection: Combination of aptamer-target recognition and T7 exonuclease-assisted cycling signal amplification.
abstract: The expression profile of vascular endothelial growth factor (VEGF) is highly correlated with the occurrence and development of cancer. This work reports an electrochemiluminescence (ECL) approach for highly sensitive detection of VEGF165. This approach comprises aptamer-target recognition, T7 exonuclease (T7 Exo)-assisted cycling signal amplification and efficient quenching of ECL of CdS:Eu nanocrystals (NCs) by using DNAzyme. In this assay, CdS:Eu NCs were used as the ECL substrate, A guanine (G)-rich single-stranded DNA (ssDNA) sequence and VEGF165 aptamer were co-immobilized on the surface of the CdS:Eu NCs modified glassy carbon electrode. After recognition and binding to VEGF165, the aptamer moved away from the electrode surface and induced the proposed cyclic cleavage of the target DNA with T7 Exo. A large amount of G-rich ssDNA was released on the CdS:Eu film and folded into G-quadruplex/hemin DNAzyme in the presence of hemin and K(+), consequently decreasing the ECL intensity of CdS:Eu. A good linearity was obtained for VEGF165 detection within the range of 1 pM to 20 nM with a detection limit of 0.2 pM. This assay could be a universal and promising protocol for detection of various biomarkers for early clinical diagnosis.
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China. Electronic address: zhangh@njnu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Meixing
authors.initials: M
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Caihong
authors.initials: C
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Huilei
authors.initials: H
authors.lastname: Dong
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China. Electronic address: cxcai@njnu.edu.cn.
authors.forename: Chenxin
authors.initials: C
authors.lastname: Cai
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation; D019187:Cadmium Compounds / Q000737:chemistry*; D021881:DNA, Catalytic / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005063:Europium / Q000737:chemistry*; D005090:Exodeoxyribonucleases / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D020033:Protein Isoforms / Q000032:analysis / Q000097:blood; D013440:Sulfides / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000097:blood*
chemical_list: D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D021881:DNA, Catalytic; D020033:Protein Isoforms; D013440:Sulfides; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C034939:cadmium sulfide; D005063:Europium; D005090:Exodeoxyribonucleases; C046264:gene b exonuclease
keywords: Aptamer; Electrochemiluminescence; Exonuclease; Signal amplification; Vascular endothelial growth factor