title: Label-free amperometric immunobiosensor based on a gold colloid and Prussian blue nanocomposite film modified carbon ionic liquid electrode.
abstract: A novel experimental methodology based on a Prussian blue (PB) and gold nanoparticles (AuNPs) modified carbon ionic liquid electrode (CILE) was developed for use in a label-free amperometric immunosensor for the sensitive detection of human immunoglobulin G (HIgG) as a model protein. The CILE was fabricated by using the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate as binder. Controllable electrodeposition of PB on the surface of the CILE and coating with 3-aminopropyl triethylene silane (APS) formed a film with high electronic catalytic activity and large surface area for the assembly of AuNPs and further immobilization of HIgG antibody. The electrochemistry of the formed nanocomposite biofilm was investigated by electrochemical techniques including cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. The HIgG concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased differential pulse voltammetric values were proportional to the HIgG concentration in two ranges, 0.05-1.25 ng mL(-1) and 1.25-40 ng mL(-1), with a detection limit of 0.001 ng mL(-1) (S/N = 3). This electrochemical immunoassay combined the specificity of the immunological reaction with the sensitivity of the AuNPs, ionic liquid, and PB amplified electrochemical detection and would therefore be valuable for clinical immunoassays.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Ke-Jing
authors.initials: KJ
authors.lastname: Huang
authors.forename: De-Jun
authors.initials: DJ
authors.lastname: Niu
authors.forename: Jun-Yong
authors.initials: JY
authors.lastname: Sun
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Zhu
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D004566:Electrodes; D005295:Ferrocyanides / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis*; D052578:Ionic Liquids / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*
chemical_list: D005295:Ferrocyanides; D007074:Immunoglobulin G; D052578:Ionic Liquids; D002244:Carbon; D006046:Gold; C000170:ferric ferrocyanide