title: Enhanced colorimetric immunoassay accompanying with enzyme cascade amplification strategy for ultrasensitive detection of low-abundance protein.
abstract: Methods based on enzyme labels have been developed for colorimetric immunoassays, but most involve poor sensitivity and are unsuitable for routine use. Herein, we design an enhanced colorimetric immunoassay for prostate-specific antigen (PSA) coupling with an enzyme-cascade-amplification strategy (ECAS-CIA). In the presence of target PSA, the labeled alkaline phosphatase on secondary antibody catalyzes the formation of palladium nanostructures, which catalyze 3,3',5,5'-tetramethylbenzidine-H2O2 system to produce the colored products, thus resulting in the signal cascade amplification. Results indicated that the ECAS-CIA presents good responses toward PSA, and allows detection of PSA at a concentration as low as 0.05 ng mL(-1). Intra- and inter-assay coefficients of variation are below 9.5% and 10.7%, respectively. Additionally, the methodology is validated for analysis of clinical serum specimens with consistent results obtained by PSA ELISA kit. Importantly, the ECAS-CIA opens a new horizon for protein diagnostics and biosecurity.
authors: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China.
authors: Zhuangqiang
authors: Z
authors: Gao
authors: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China.
authors: Li
authors: L
authors: Hou
authors: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China.
authors: Mingdi
authors: M
authors: Xu
authors: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China.
authors: Dianping
authors: D
authors: Tang
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001560:Benzidines / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002384:Catalysis; D003124:Colorimetry / Q000379:methods*; D057075:Enzyme Assays / Q000379:methods*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D008297:Male; D053768:Metal Nanoparticles; D010165:Palladium; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000097:blood* / Q000276:immunology; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D001560:Benzidines; D015415:Biomarkers; C021758:3,3',5,5'-tetramethylbenzidine; D010165:Palladium; D006861:Hydrogen Peroxide; D000469:Alkaline Phosphatase; D017430:Prostate-Specific Antigen