title: A sensitive immunoassay based on electropolymerized films by capacitance measurements for direct detection of immunospecies.
abstract: Fabrication of a capacitive immunosensor based on electropolymerized polytyramine (Pty) film for the direct detection of human serum albumin (HSA) without any labeling is described. The capacitance change of the heterostructures, Pty films/covalently bonded antibodies/buffered medium, is utilized for monitoring the specific antibody-antigen interaction. The Pty films are ultrathin and the HSA assay is nearly specific. Experimental parameters affecting antibody immobilization and the sensing of HSA are investigated in detail and optimized. This capacitive sensor prepared with the present method can provide high sensitivity. Under the optimized experimental conditions, a linear calibration curve in the concentration range 1.84-368.6 ng/ml when plotted vs the logarithm of the antigen concentration is obtained and the detection limit (S/N=3) is 1.60 ng/ml. After an acidic washing the present system can be used again. The applicability and reliability of the sensor are also demonstrated.
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Zai-Sheng
authors.initials: ZS
authors.lastname: Wu
authors.forename: Ji-Shan
authors.initials: JS
authors.lastname: Li
authors.forename: Ting
authors.initials: T
authors.lastname: Deng
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Luo
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D000818:Animals; D002417:Cattle; D025802:Electric Capacitance; D004563:Electrochemistry; D017979:Gold Colloid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis* / Q000737:chemistry / Q000276:immunology*
chemical_list: D017979:Gold Colloid; D011108:Polymers; D012709:Serum Albumin