title: A novel multiple signal amplifying immunosensor based on the strategy of in situ-produced electroactive substance by ALP and carbon-based Ag-Au bimetallic as the catalyst and signal enhancer.
abstract: In this work, a novel immunosensor was constructed based on the alkaline phosphatase (ALP) in situ generating an electroactive substance by enzymatic hydrolysis the inactive substrates. The new signal-amplified strategy for sensitive detection of HIgG was based on the catalytic oxidation of ALP-generated products, ascorbic acid (AA), using carbon-based Ag-Au bimetallic as the catalyst and signal enhancer. Through a sandwich reaction, ALP-Ab2bioconjugates were captured on the electrode surface and the amplified signal can be obtained as follows: the ALP catalyzed the inactive substrate L-ascorbic acid 2-phosphate (AAP) to in situ produce AA; AA as an electroactive product then can be directly electro-oxidized to generate electrochemical signal; At the same time, AA could be catalytic oxidized by Ag-Au bimetallic and resulted in the amplification of electrochemical signal; Finally, the oxidation of Ag on the Ag-Au bimetallic maybe further enhance the detection signal. The proposed immunosensor achieved good linear in the range of 0.005-100ngmL-1with the detection limit of 0.0009ngmL-1(S/N =3). The proposed immunosensor was successfully applied in the analysis of human IgG in real samples and got satisfied results. The present work demonstrates a general strategy for the design of multifunctional nanomaterials based on carbon-based bimetallic nanoparticles for different applications, such as biosensors, immunosensors and nanocatalysts.
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Si
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Renkai
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Science, Science and technological innovation platform, Hunan Agricultural University, Changsha 410128, Hunan, PR China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Liuqing
authors.initials: L
authors.lastname: Yang
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Qiujun
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China. Electronic address: liuml@hunnu.edu.cn.
authors.forename: Meiling
authors.initials: M
authors.lastname: Liu
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Youyu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry*; D000818:Animals; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D006041:Goats; D006046:Gold / Q000737:chemistry*; D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry; D007124:Immunoenzyme Techniques / Q000379:methods*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D009842:Oligopeptides / Q000032:analysis / Q000097:blood*; D012834:Silver / Q000737:chemistry*
chemical_list: D018796:Immunoconjugates; D037742:Nanotubes, Carbon; D009842:Oligopeptides; C011669:ascorbate-2-phosphate; C029275:hippuryl-glycyl-glycine; D012834:Silver; D002244:Carbon; D006046:Gold; D000469:Alkaline Phosphatase; D001205:Ascorbic Acid
keywords: Ag-Au bimetallic; Alkaline phosphatase; Catalytic oxidation of AA; Signal amplification