title: Ratiometric electrochemical proximity assay for sensitive one-step protein detection.
abstract: This work proposes the concept of ratiometric electrochemical proximity assay (REPA), which can be used for one-step, highly sensitive and selective detection of protein. The assay strategy was achieved on a sensing interface that was formed by hybridization of methylene blue (MB)-labeled antibody-DNA probe (MB-DNA1-Ab1) with ferrocene (Fc)-labeled DNA capture probe (Fc-P) modified gold electrode. On the interface the target protein could trigger the formation of immunocomplex between MB-DNA1-Ab1 and detection antibody-DNA probe (Ab2-DNA2) and subsequently the proximity hybridization of DNA1-DNA2, which led to the departure of MB-DNA1-Ab1 from the interface. The remained Fc-P could form a hairpin structure to take Fc group to electrode surface. Therefore, the recognition of target protein to Ab1 and Ab2 resulted in both the "signal-off" of MB and the "signal-on" of Fc for dual-signal electrochemical ratiometric readout. The proposed REPA could be carried out in one-step with 40-min duration and showed a wide detection range from 0.05 to 100 ng/mL with pg/mL limit of detection, displaying great potential for convenient point-of-care testing and commercial application.
authors.affiliation: 1] State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, P.R. China [2].
authors.forename: Kewei
authors.initials: K
authors.lastname: Ren
authors.affiliation: 1] State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, P.R. China [2].
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Jiangsu Institute of Cancer Prevention and Cure, Nanjing 210009, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, P.R. China.
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D000906:Antibodies / Q000737:chemistry; D000936:Antigen-Antibody Complex / Q000737:chemistry; D015374:Biosensing Techniques; D002138:Calibration; D015342:DNA Probes / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry; D057230:Limit of Detection; D008297:Male; D000075163:Metallocenes; D008751:Methylene Blue / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000097:blood*
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D015342:DNA Probes; D005296:Ferrous Compounds; D007141:Immunoglobulin Fc Fragments; D000075163:Metallocenes; D006046:Gold; D017430:Prostate-Specific Antigen; D008751:Methylene Blue; C004998:ferrocene