title: Nanobody-Based Electrochemical Immunoassay for Ultrasensitive Determination of Apolipoprotein-A1 Using Silver Nanoparticles Loaded Nanohydroxyapatite as Label.
abstract: Nanobodies (Nbs), derived from camelid heavy-chain antibodies, have distinct advantages over conventional antibodies in immunoassay. In this work, Nbs (Nb11 and Nb19) that can bind to different epitopes on apolipoprotein-A1 (Apo-A1) were screened out from an immunized Bactrian camel for the first time. Nb11 was used as capture antibody and fixed on gold nanoparticles (Au NPs) modified screen-printed carbon electrode (SPCE). The silver nanoparticles loaded nanohydroxyapatite (Ag-nHAP) was used as signal tag to label secondary antibody Nb19. A sandwich-type immunological reaction occurred between Apo-A1 and the two Nbs, which brought the Ag-nHAP to the SPCE surface. After the Ag-nHAP were acidically dissolved in the microelectrolytic cell of the SPCE, stripping voltammetric measurement for the released silver ions was performed to obtain an amplified signal. The peak current values increased by the logarithmic values of Apo-A1 concentrations from 10(-4) to 50 ng mL(-1) under optimal conditions. The detection limit was calculated to be 0.02 pg mL(-1). This method was used for the serum samples analysis and achieved satisfactory results. The low cost and high sensitivity make the electrochemical immunosensor suitable for the Apo-A1 detection, which may find promising application in other fields.
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Pudong, Shanghai, 201203, P.R. China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.
authors.forename: Yihe
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Pudong, Shanghai, 201203, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Ma
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Du
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan , Jinan, Shandong 250022, P.R. China.|CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road, Pudong, Shanghai, 201203, P.R. China.
authors.forename: Yakun
authors.initials: Y
authors.lastname: Wan
mesh_terms: D000818:Animals; D016632:Apolipoprotein A-I / Q000032:analysis* / Q000276:immunology; D002162:Camelus; D017886:Durapatite / Q000737:chemistry* / Q000276:immunology; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry* / Q000276:immunology; D007118:Immunoassay / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry* / Q000276:immunology; D057127:Single-Chain Antibodies / Q000276:immunology*
chemical_list: D016632:Apolipoprotein A-I; D057127:Single-Chain Antibodies; D012834:Silver; D006046:Gold; D017886:Durapatite