title: Magnetic-particle-based, ultrasensitive chemiluminescence enzyme immunoassay for free prostate-specific antigen.
abstract: We report a magnetic-particle (MMP)-based chemiluminescence enzyme immunoassay (CLEIA) for free prostate-specific antigen (f-PSA) in human serum. In this method, the f-PSA is sandwiched between the anti-PSA antibody coated MMPs and alkaline phosphatase (ALP)-labeled anti-f-PSA antibody. The signal produced by the emitted photons from the chemiluminescent substrate (4-methoxy-4-(3-phosphatephenyl)-spiro-(1,2-dioxetane-3,2'-adamantane)) is directly proportional to the amount of f-PSA in a sample. The present MMP-based assay can detect f-PSA in the range of 0.1-30 ng mL(-1) with the detection limit of 0.1 ng mL(-1). The linear detection range could match the concentration range within the "diagnostic gray zone" of serum f-PSA levels (4-10 ng mL(-1)). The detection limit was sufficient for measuring clinically relevant f-PSA levels (>4 ng mL(-1)). Furthermore, the method was highly selective; it was unaffected by cross-reaction with human glandular kallikrein-2, a kallikrein-like serine protease that is 80% similar to f-PSA. The proposed method was finally applied to determine f-PSA in 40 samples of human sera. Results obtained using the method showed high correlation with those obtained using a commercially available microplate CLEIA kit (correlation coefficient, 0.9821). This strategy shows great potential application in the fabrication of diagnostic kits for determining f-PSA in serum.
authors.affiliation: College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Ruping
authors.initials: R
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Quan
authors.initials: Q
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhao
authors.initials: Z
authors.lastname: Yue
authors.forename: Guohua
authors.initials: G
authors.lastname: Liu
mesh_terms: D000906:Antibodies / Q000378:metabolism; D003429:Cross Reactions; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay; D008163:Luminescent Measurements; D008280:Magnetics; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood*; D012698:Serologic Tests / Q000379:methods*; D020840:Tissue Kallikreins / Q000097:blood / Q000737:chemistry
chemical_list: D000906:Antibodies; D020840:Tissue Kallikreins; D017430:Prostate-Specific Antigen
keywords: Chemiluminescence immunoassay; Free prostate-specific antigen; Magnetic particles; Prostate cancer; Solid-phase immunoassay