Title of article :
Reagentless Amperometric Immunosensors Based on Direct Electrochemistry of Horseradish Peroxidase for Determination of Carcinoma Antigen-125
Author/Authors :
Ju، Huangxian نويسنده , , Dai، Zong نويسنده , , Yan، Feng نويسنده , , CHEN، JIN نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2003
Pages :
-5428
From page :
5429
To page :
0
Abstract :
A novel strategy for immunoassay and the preparation of reagentless immunosensors was proposed. This strategy was based on the immobilization of antigen and the direct electrochemistry of horseradish peroxidase (HRP) that was labeled to an antibody. A reagentless immunosensor for carcinoma antigen-125 (CA 125) determination was developed. The immunosensor was prepared by immobilizing CA 125 with titania sol-gel on a glassy carbon electrode by the vapor deposition method. The incubation of the immunosensor in phosphate buffer solution (PBS) including HRP-labeled CA 125 antibody led to the formation of a HRP-modified surface. The immobilized HRP displayed its direct electrochemistry with a rate constant of 3.04 ± 1.21 s-1. With a competition mechanism, a differential pulse voltammetric determination method for CA 125 was established by the peak current decrease of the immobilized HRP. The current decrease resulted from the competitive binding of the CA 125 in sample solution and the immobilized CA 125 to the limited amount of HRP-labeled CA 125 antibody. Under optimal conditions, the current decrease was proportional to CA 125 concentration ranging from 2 to 14 units mL-1 with a detection limit of 1.29 units mL-1 at a current decrease by 10%. The CA 125 immunosensor showed good accuracy and acceptable precision and fabrication reproducibility with intraassay CVs of 8.7 and 5.5% at 8 and 14 units mL-1 CA 125 concentrations, respectively, and interassay CV of 19.8% at 8 units mL-1. The storage stability was acceptable in a pH 7.0 PBS at 4 (degree)C for 15 days. The proposed method provided a new promising platform for clinical immunoassay.
Keywords :
Shelterbelts , Hedges , Field margins , Yield gains , Crop yields
Journal title :
Analytical Chemistry
Serial Year :
2003
Journal title :
Analytical Chemistry
Record number :
51565
Link To Document :
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