title: Electrochemical immunosensor for norethisterone based on signal amplification strategy of graphene sheets and multienzyme functionalized mesoporous silica nanoparticles.
abstract: Norethisterone is one kind of widely used anabolic steroid hormones which can help to promote livestock growth and sometime has been illegally used for livestock breeding. The residues of norethisterone in animal food will harm people's health, therefore, it has been banned to use for the growth promotion purposes in livestock. In this study, amino-group functionalized mesoporous silica nanoparticles (MSN) were prepared and used to immobilize Au nanoparticles, which was further utilized for the adsorption of horseradish peroxidase (HRP) and the secondary antibody (Ab2). The resulting nanoparticles, Au-MSN-HRP-Ab2 were used as labels for immunosensors to detect norethisterone antigen. A sandwich-type protocol was used to prepare the immunosensor with the primary antibody (Ab1) immobilized onto thionine (TH) and graphene sheet (GS) modified glassy carbon electrode surface. The sensitivity of the sandwich-type immunosensor using Au-MSN-HRP-Ab2 as labels for norethisterone antigen detection was much higher than that using either Au-MSN-Ab2 or MSN-HRP-Ab2 as labels. Within norethisterone concentration range (0.01-10 ng/mL), a linear calibration plot (Y=0.55671+8.27101X, r=0.9993) was obtained with a detection limit of 3.58 pg/mL under optimal conditions. The proposed immunosensor shows good reproducibility, selectivity, and acceptable stability. This new type of labels for immunosensors may provide many potential applications for the detection of growth hormone in animal derived food.
authors.affiliation: School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xin
authors.forename: Bin
authors.initials: B
authors.lastname: Du
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Han
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Cai
authors.forename: Ru
authors.initials: R
authors.lastname: Li
authors.forename: Minghui
authors.initials: M
authors.lastname: Yang
authors.forename: He
authors.initials: H
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000276:immunology; D007118:Immunoassay / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009640:Norethindrone / Q000032:analysis* / Q000737:chemistry; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D012822:Silicon Dioxide; D006108:Graphite; D006735:Horseradish Peroxidase; D009640:Norethindrone