title: Sensitive reagentless electrochemical immunosensor based on an ormosil sol-gel membrane for human chorionic gonadotrophin.
abstract: A new organically modified silicate (ormosil) material was synthesized as a matrix to encapsulate enzyme labeled antibody for preparation of immunosensors. The ormosil matrix was prepared by hydrolyzing tetraethyoxysilane and (3-aminopropyl)triethoxysilane in weak alkali solution. It possessed three-dimensional ordered nanoporous structure with high electrical conductivity and good mechanical stability. Its hydrophilicity provided a microenvironment for retaining the biological activity of the immobilized protein. Particularly, using horseradish peroxidase-labeled human chorionic gonadotrophin antibody (HRP-anti-hCG) as a model, the immobilized HRP showed direct electron transfer at about -35 mV with a rate constant of 15.8+/-3.8s(-1). By a simple one-step immunoreaction between human serum chorionic gonadotrophin (hCG) in sample solution and the immobilized HRP-anti-hCG, the differential pulse voltammetric peak current of HRP decreased linearly with an increasing hCG concentration from 0.5 to 50 mIU/ml with a relatively low limit of detection of 0.3 mIU/ml at 3sigma. Excellent analytical performance, fabrication reproducibility and operational stability of the proposed biosensor indicated its promising application in clinical diagnostics.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science (Education Ministry of China), Department of Chemistry, Nanjing University, Nanjing 210093, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Tan
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D006063:Chorionic Gonadotropin / Q000032:analysis*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D005782:Gels; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D012680:Sensitivity and Specificity; D012833:Siloxanes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D006063:Chorionic Gonadotropin; D005782:Gels; D012833:Siloxanes; C510784:ormosil