Noncompetitive immunoassay for carcinoembryonic antigen in human serum by microchip electrophoresis for cancer diagnosis.
BACKGROUND
Carcinoembryonic antigen (CEA) as one of the most widely used tumor markers is used in the clinical diagnosis of colorectal, pancreatic, gastric, and cervical carcinomas. We describe a microchip electrophoresis (MCE)-based noncompetitive immunoassay technique for assaying CEA in human serum for cancer diagnosis.


METHODS
Based on a noncompetitive immunoassay format, CEA reacts first with an excess amount of monoclonal antibody (Ab(1)), then free Ab(1) and the bound CEA-Ab(1) complex react with an excess amount of fluorescein isothiocyanate (FITC)-labeled secondary antibody (Ab(2)*) to form CEA-Ab(1)-Ab(2)* and Ab(1)-Ab(2)* complexes. Finally, the free Ab(2)* and bound CEA-Ab(1)-Ab(2)*, Ab(1)-Ab(2)* complexes were separated and detected by MCE coupling laser-induced fluorescence (LIF), and CEA was quantified by measuring the fluorescence intensity of CEA-Ab(1)-Ab(2)*.


RESULTS
The linear range for CEA was 60pg/ml-8ng/ml with a correlation coefficient of 0.9992 and a detection limit of 45.7pg/ml. The immunocomplex including CEA-Ab(1)-Ab(2)*, Ab(1)-Ab(2)*and free Ab(2)* was separated within 80s. The amounts of CEA in normal person serum were found to be in the range of 2.9-5.1microg/l, and seven cancer patients serum were analyzed, and CEA levels range from 79.6-270.1ng/ml.


CONCLUSIONS
This method may become a useful tool for rapid analysis of CEA and other tumor markers in biomedical analysis and clinical diagnosis.
Ye
Fanggui
F
Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin 51004, PR China.
Shi
Ming
M
Huang
Yong
Y
Zhao
Shulin
S
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D001774:Blood Chemical Analysis / Q000379:methods*; D002021:Buffers; D002272:Carcinoembryonic Antigen / Q000097:blood* / Q000276:immunology / Q000302:isolation & purification; D004560:Electricity; D004586:Electrophoresis / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods*; D007267:Injections; D046208:Microchip Analytical Procedures / Q000379:methods*; D009369:Neoplasms / Q000097:blood* / Q000175:diagnosis*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D000911:Antibodies, Monoclonal; D002021:Buffers; D002272:Carcinoembryonic Antigen; D012967:Sodium Dodecyl Sulfate; D016650:Fluorescein-5-isothiocyanate