title: Naked-eye sensitive ELISA-like assay based on gold-enhanced peroxidase-like immunogold activity.
abstract: A naked-eye sensitive ELISA-like assay was developed based on gold-enhanced peroxidase-like activity of gold nanoparticles (AuNPs). Using human IgG (H-IgG) as an analytical model, goat anti-human IgG antibody (anti-IgG) adsorbed on microtiter plate and AuNPs-labeled anti-IgG acted as capture antibody and detection antibody, respectively. Because the surfaces of AuNPs were blocked by protein molecules, the peroxidase-like activity of AuNPs was almost inhibited, evaluated by the catalytic oxidation of peroxidase enzyme substrate 3,3',5,5'-tetramethylbenzidine (TMB), which could produce a bright blue color in the presence of H2O2. Fortunately, the catalytic ability of AuNPs was dramatically increased by the deposition of gold due to the formation of a new gold shell on immunogold. Under optimal reaction conditions, the colorimetric immunoassay presented a good linear relationship in the range of 0.7-100 ng/mL and the limit of detection (LOD) of 0.3 ng/mL calculated by 3σ/S for UV-vis detection, and obtained LOD of 5 ng/mL for naked-eye detection. The obtained results were competitive with conventional sandwich ELISA with the LOD of 1.6 ng/mL. Furthermore, this developed colorimetric immunoassay was successfully applied to diluted human serum and fetal bovine serum samples, and predicted a broad prospect for the use of peroxidase-like activity involving nanomaterials in bioassay and diagnostics.
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors.forename: Zhaopeng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Bionano Technology, Hanyang University, Ansan, 426-791, Republic of Korea.
authors.forename: Jaebum
authors.initials: J
authors.lastname: Choo
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China. lxchen@yic.ac.cn.
authors.forename: Lingxin
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D001560:Benzidines / Q000737:chemistry / Q000378:metabolism; D003124:Colorimetry / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation / Q000379:methods; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D009195:Peroxidase / Q000737:chemistry
chemical_list: D000906:Antibodies; D001560:Benzidines; D007074:Immunoglobulin G; C021758:3,3',5,5'-tetramethylbenzidine; D006046:Gold; D009195:Peroxidase
keywords: Colorimetric immunoassay; Gold enhancement; Gold nanoparticles; Human IgG; Peroxidase-like activity