title: DNA-based hybridization chain reaction for an ultrasensitive cancer marker EBNA-1 electrochemical immunosensor.
abstract: An ultrasensitive and selective electrochemical immunosensor was developed for the detection of Epstein Barr virus nuclear antigen 1 (EBNA-1). Firstly, a suspension of graphene sheets (GS) and multi-walled carbon nanotubes (MWCNTs) was prepared with the aid of chitosan (CS) solution and then modified on a glassy carbon electrode (GCE). Gold nanoparticles (AuNPs) were then electrodeposited onto the surface of the GS-MWCNTs film by cyclic voltammetry (CV) to immobilize the captured antibodies. After that, specific sandwich immunoreactions were formed among the captured antibody, EBNA-1, and secondary antibody, DNA-coated carboxyl multi-wall carbon nanotubes (DNA-MWCNTs-Ab2). DNA initiator strands (S0) and secondary antibodies linked to the MWCNTs and double-helix DNA polymers were obtained by hybridization chain reaction (HCR), and here S0 on the MWCNTs propagates a chain reaction of hybridization events between two alternating hairpins to form a nicked double-helix. Finally, electroactive indicator doxorubicin hydrochloride was intercalated into the CG-GC steps between the HCR products and could produce an electrochemical signal, which was monitored by differential pulse voltammetry (DPV). Under optimum conditions, the amperometric signal increased linearly with the target concentrations (0.05-6.4ngmL(-1)), and the immunosensor exhibited a detection limit as low as 0.7pgmL(-1) (S/N=3). The proposed method showed acceptable stability and reproducibility, as well as favorable recovery for EBNA-1 in human serum. The proposed immunosensor provides a novel avenue for signal amplification and potential applications in bioanalysis and clinical diagnostics.
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, No. 1 Yi Xue Yuan Road, Chongqing 400016, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Song
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, No. 1 Yi Xue Yuan Road, Chongqing 400016, PR China.
authors.forename: Guoming
authors.initials: G
authors.lastname: Xie
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, No. 1 Yi Xue Yuan Road, Chongqing 400016, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, No. 1 Yi Xue Yuan Road, Chongqing 400016, PR China.
authors.forename: Lingzhi
authors.initials: L
authors.lastname: Liu
authors.affiliation: Guiyang Medical College, Guiyang 55004, PR China.
authors.forename: Guang
authors.initials: G
authors.lastname: Tian
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, No. 1 Yi Xue Yuan Road, Chongqing 400016, PR China. Electronic address: xianghuacq@163.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Xiang
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D019309:Epstein-Barr Virus Nuclear Antigens / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D017403:In Situ Hybridization / Q000295:instrumentation*
chemical_list: D014408:Biomarkers, Tumor; D019309:Epstein-Barr Virus Nuclear Antigens; D004247:DNA; C417029:EBV-encoded nuclear antigen 1
keywords: Doxorubicin hydrochloride; EBNA-1; GS–MWCNTs; Hybridization chain reaction; Immunosensor