A novel microchip electrophoresis-based chemiluminescence immunoassay for the detection of alpha-fetoprotein in human serum

A sensitive immunoassay method based on microchip electrophoresis chemiluminescence (MCE-CL) detection technology was developed for the detection of tumor marker alpha-fetoprotein (AFP). This method adopts the non-competitive immunoassay mode, and was conducted after AFP reacted with excessive horseradish peroxidase (HRP) labeled monoclonal antibody. The extreme pH value was adopted in the electrophoresis buffer solution. The use of brij 35 as an additive of electrophoresis buffer increased dramatically the resolution (Rs) and the reproducibility of the analysis. Under the optimized experimental conditions, effective separation of the immune complex Ag-Ab* and free Ab* was achieved within 60 s. The peak height of the immune complex Ag-Ab* was taken as quantification of AFP. Good linearity was observed within AFP concentrations ranging from 10 ng/mL to 150 ng/mL, and the detection limit was found to be 7.2 ng/mL (1.0x10(-10) M). The present method was successfully applied for the detection of AFP in human serum from both healthy and cancer patients, and the AFP levels in the both were found be in the range of 16.5-23.4 ng/mL and 416.2-825.4 ng/mL, respectively.