title: Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase.
abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab1) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab2) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core-shell Au-SiO2@Fe3O4 nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab2) through the Au-SH or Au-NH3(+) interaction, and HRP was also used as the block reagent. The formation of antigen-antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL(-1) with a detection limit of 0.01 U mL(-1). Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from the commercialized electrochemiluminescent method.
authors.affiliation: College of Sciences, Nanjing Tech University, Nanjing 211816, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: College of Sciences, Nanjing Tech University, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China. Electronic address: chenxj_njut@126.com.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Chen
authors.affiliation: Zhangjiagang Hospital of Traditional Chinese Medicine, Zhangjiagang 215600, PR China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Tang
authors.affiliation: College of Sciences, Nanjing Tech University, Nanjing 211816, PR China.
authors.forename: Lingna
authors.initials: L
authors.lastname: Ge
authors.affiliation: College of Sciences, Nanjing Tech University, Nanjing 211816, PR China.
authors.forename: Buhua
authors.initials: B
authors.lastname: Guo
authors.affiliation: College of Sciences, Nanjing Tech University, Nanjing 211816, PR China. Electronic address: yaochengnjut@163.com.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yao
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques; D018395:CA-19-9 Antigen / Q000032:analysis* / Q000276:immunology; D055664:Electrochemical Techniques; D004566:Electrodes; D004797:Enzyme-Linked Immunosorbent Assay; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D055767:Immobilized Proteins / Q000737:chemistry / Q000276:immunology; D008280:Magnetics; D049329:Nanostructures / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D000906:Antibodies; D018395:CA-19-9 Antigen; D004800:Enzymes, Immobilized; D055767:Immobilized Proteins; C509969:SBA-15; D006046:Gold; D012822:Silicon Dioxide; D006735:Horseradish Peroxidase; D052203:Ferrosoferric Oxide
keywords: Carbohydrate antigen 19-9; Direct electron transfer; Horseradish peroxidase; Magnetic nanocomposites; Sandwich-type electrochemical immunosensor; Three dimensional ordered macroporous magnetic electrode