DNA-based hybridization chain reaction for amplified bioelectronic signal and ultrasensitive detection of proteins.
This work reports a novel electrochemical immunoassay protocol with signal amplification for determination of proteins (human IgG here used as a model target analyte) at an ultralow concentration using DNA-based hybridization chain reaction (HCR). The immuno-HCR assay consists of magnetic immunosensing probes, nanogold-labeled signal probes conjugated with the DNA initiator strands, and two different hairpin DNA molecules. The signal is amplified by the labeled ferrocene on the hairpin probes. In the presence of target IgG, the sandwiched immunocomplex can be formed between the immobilized antibodies on the magnetic beads and the signal antibodies on the gold nanoparticles. The carried DNA initiator strands open the hairpin DNA structures in sequence and propagate a chain reaction of hybridization events between two alternating hairpins to form a nicked double-helix. Numerous ferrocene molecules are formed on the neighboring probe, each of which produces an electrochemical signal within the applied potentials. Under optimal conditions, the immuno-HCR assay presents good electrochemical responses for determination of target IgG at a concentration as low as 0.1 fg mL(-1). Importantly, the methodology can be further extended to the detection of other proteins or biomarkers.
Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & Ministry of Education of China), Department of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China.
Bing
B
Zhang
Bingqian
B
Liu
Dianping
D
Tang
Reinhard
R
Niessner
Guonan
G
Chen
Dietmar
D
Knopp
D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D055029:Inverted Repeat Sequences; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry; D000075163:Metallocenes; D009693:Nucleic Acid Hybridization
D015342:DNA Probes; D005296:Ferrous Compounds; D007074:Immunoglobulin G; D000075163:Metallocenes; D006046:Gold; D004247:DNA; C004998:ferrocene