A rapid and sensitive chemiluminescence immunoassay based on magnetic particles for squamous cell carcinoma antigen in human serum

Background: Because squamous cell carcinoma antigen (SCCa) quantification has demonstrated strong clinical potential, we describes rapid and highly sensitive magnetic particle-based chemiluminescence immunoassay (CLIA) technique for assaying SCCa in serum. Methods: Fluorescein isothiocyanate (FITC) and N-(aminobutyl)-N-(ethylisoluminol) (ABEI) were used to label 2 different monoclonal antibodies of anti-SCCa. Both of the labeled antibodies combined with SCCa to form a sandwiched immunoreaction that was monitored by chemiluminescence (CL) detection. The magnetic particles (MPs) that were coated with anti-FITC antibody served as both the solid phase and the separator. The relevant variables involved in the CLIA signals were optimized and the parameters of the proposed method were evaluated. Results: The method was linear to 20 ng/ml SCCa with a detection limit of 0.02 ng/ml. The intra-assay imprecision results [mean (CV)] were 1.12 ng/ml (3.81%), 2.58 ng/ml (2.53%) and [6.56 ng/ml (2.24%)]: the inter-assay imprecision results were 11.18 ng/ml (5.26%)], [2.49 ng/ml (4.75%)] and 16.61 ng/ml (4.29%)]. The average recoveries were between 97% and 104%. The relationship between the concentration of diluted SCCa and the dilution ratios gave a linear correlation coefficient of 0.9995. A correlation analysis against an established automated assay generated a slope of 0.9929 and an intercept of 0.0039 ng/ml (r = 0.9964). Conclusions: The proposed method demonstrates an acceptable performance for quantifying serum SCCa and is suitable for the fabrication of a commercial kit with application in the automated CL analyzer. (C) 2011 Elsevier B.V. All rights reserved.