title: Ultrasensitive electrochemical DNA biosensor based on functionalized gold clusters/graphene nanohybrids coupling with exonuclease III-aided cascade target recycling.
abstract: In this work, a novel and ultrasensitive electrochemical biosensor was constructed for DNA detection based on functionalized gold clusters/graphene nanohybrids (AuNCs/GR nanobybrids) and exonuclease III (Exo III)-aided cascade target recycling. By utilizing the capacity of GR as universal template, different metal nanoclusters including AuNCs/GR nanobybrids and PtNCs/GR nanohybrids were synthesized through convenient ultrasonic method. Exo III-aided cascade recycling was initiated by target DNA, generating the final cleavage product (S2), which acted as a linkage between capture probe and the functionalized metal nanoclusters/GR conjugates in the construction of the biosensor. The AuNCs/GR-DNA-enzyme conjugates acted as interfaces of enzyme-catalyzed silver deposition reaction, achieving DNA detection ranging from 0.02 fM to 20 pM with a detection limit of 0.057 fM. In addition, PtNCs/GR-DNA conjugates presented peroxidase-like activity and the functionalized PtNCs/GR nanohybrids-based electrochemical biosensor also realized DNA detection by catalyzing the 3,3',5,5'-tetramethylbenzidine-hydrogen peroxide (TMB-H2O2) system to produce electrochemical signal. This metal clusters/GR-based multiple-amplified electrochemical biosensor provided an universal method for DNA detection.
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Bao
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Huayu
authors.initials: H
authors.lastname: Xiong
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China. Electronic address: wangsf@hubu.edu.cn.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Wang
mesh_terms: D001560:Benzidines / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D002384:Catalysis; D004247:DNA / Q000032:analysis* / Q000097:blood; D055664:Electrochemical Techniques / Q000379:methods*; D005090:Exodeoxyribonucleases / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009195:Peroxidase / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D012834:Silver / Q000737:chemistry
chemical_list: D001560:Benzidines; C021758:3,3',5,5'-tetramethylbenzidine; D012834:Silver; D010984:Platinum; D006046:Gold; D006108:Graphite; D004247:DNA; D006861:Hydrogen Peroxide; D009195:Peroxidase; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III
keywords: AuNCs/GR nanohybrids; Electrochemical biosensor; Enzyme-catalyzed silver deposition; Exonuclease III-aided cascade target recycling; Target DNA