A disposable multianalyte electrochemical immunosensor array for automated simultaneous determination of tumor markers

Background: Automated and convenient multianalyte detection with high throughput is increasingly needed in clinical diagnosis. We developed a disposable 4-by-2 array for programmed simultaneous amperometric immunoassay of 4 tumor markers. Methods: We used a screen-printed technique, 1-step immobilization method, and flow injection technique. We immobilized carcinoembryonic antigen, alpha-fetoprotein, beta-human choriogonadotropin, and carcinoma antigen 125 as model analytes in a redox mediator- grafted, biopolymer-modified, screen-printed carbon electrode array to capture corresponding horseradish peroxidase-labeled antibodies in competitive immunoreactions. The simultaneous multianalyte immunoassay was automatically carried out to amperometrically monitor the mediator-catalyzed enzymatic response to hydrogen peroxide, which decreased in proportion to the concentrations of analytes in samples. Results: The multianalyte immunosensor array had a throughput of 60 samples/h and allowed simultaneous detection of carcinoembryonic antigen, a-fetoprotein, beta-human choriogonadotropin, and carcinoma antigen 125 in clinical serum samples with concentrations up to 188 mu g/L, 250 mu g/L, 266 IU/L, and 334 kIU/L, respectively. The detection limits (limits of the blank, mean of blank plus 3 SD) were 1.1 mu g/L, 1.7 mu g/L, 1.2 IU/L, and 1.7 kIU/L. The inter- and intraassay imprecision (CVs) of the immunosensor arrays were < 7.8% and < 9.0%, respectively. The immunosensor arrays were stable for 28 days. Conclusions: This newly constructed immunosensor array provides a simple, automated, simultaneous multianalyte immunoassay with high throughput, short analytical time, and sufficiently low detection limits for clinical application. This method offers the capability of miniaturizing the multianalyte detection device. (c) 2007 American Association for Clinical Chemistry.