title: A highly sensitive label-free resonance light scattering assay of carcinoembryonic antigen based on immune complexes.
abstract: As a kind of glycoprotein, carcinoembryonic antigen (CEA) is the important tumor marker for clinical diagnosis of the presence or recurrence of cancer. In this work, a novel label-free resonance light scattering (RLS) spectral CEA assay was developed based on the combination of highly selective immunoreaction and ultrasensitive RLS technique. In Tris-HCl buffer solution (pH 7.5), the specific immunoreaction between CEA antigen and mouse anti-CEA formed immune complexes which had a maximum RLS spectral peak at 389.0 nm, with the existence of physiological saline and polyethylene glycol 20,000 (PEG 20,000). Under the optimal conditions, the magnitude of enhanced RLS intensity (ΔI(RLS)) was proportional to the concentration of CEA in the range from 0.1 to 60 ng mL(-1), with a detection limit (LOD, 3σ) of 0.03 ng mL(-1). The characteristics of RLS, the CEA immunocomplex, the immune response, the ratio of CEA antigen and mouse anti-CEA, and the optimum conditions of the immunoreaction have been investigated. The CEA concentrations of 20 serum specimens detected by the developed assay showed consistent results in comparison with those obtained by commercially available enzyme-linked immunosorbent assay (ELISA) kit. And this method has many satisfying merits including label-free, sensitivity and high selectivity.
authors.affiliation: Department of Chemistry, Shantou University, Shantou 515063, China. kqlu@stu.edu.cn
authors.forename: Zhanguang
authors.initials: Z
authors.lastname: Chen
authors.forename: Yulong
authors.initials: Y
authors.lastname: Lei
authors.forename: Zhisen
authors.initials: Z
authors.lastname: Liang
authors.forename: Fengji
authors.initials: F
authors.lastname: Li
authors.forename: Lidong
authors.initials: L
authors.lastname: Liu
authors.forename: Changlong
authors.initials: C
authors.lastname: Li
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000097:blood* / Q000648:ultrastructure; D014408:Biomarkers, Tumor / Q000097:blood* / Q000276:immunology; D002272:Carcinoembryonic Antigen / Q000097:blood* / Q000276:immunology; D002417:Cattle; D003110:Colonic Neoplasms / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008027:Light; D057230:Limit of Detection; D051379:Mice; D018625:Microscopy, Atomic Force; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D000936:Antigen-Antibody Complex; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D011092:Polyethylene Glycols