title: Noncompetitive immunoassay for carcinoembryonic antigen in human serum by microchip electrophoresis for cancer diagnosis.
abstract: 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.
authors.affiliation: 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.
authors.forename: Fanggui
authors.initials: F
authors.lastname: Ye
authors.forename: Ming
authors.initials: M
authors.lastname: Shi
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Shulin
authors.initials: S
authors.lastname: Zhao
mesh_terms: 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
chemical_list: D000911:Antibodies, Monoclonal; D002021:Buffers; D002272:Carcinoembryonic Antigen; D012967:Sodium Dodecyl Sulfate; D016650:Fluorescein-5-isothiocyanate