title: Iodine-Mediated Etching of Gold Nanorods for Plasmonic ELISA Based on Colorimetric Detection of Alkaline Phosphatase.
abstract: Here, we propose a plasmonic enzyme-linked immunosorbent assay (ELISA) based on highly sensitive colorimetric detection of alkaline phosphatase (ALP), which is achieved by iodine-mediated etching of gold nanorods (AuNRs). Once the sandwich-type immunocomplex is formed, the ALP bound on the polystyrene microwells will hydrolyze ascorbic acid 2-phosphate into ascorbic acid. Subsequently, iodate is reduced to iodine, a moderate oxidant, which etches AuNRs from rod to sphere in shape. The shape change of AuNRs leads to a blue-shift of longitudinal localized surface plasmon resonance. As a result, the solution of AuNRs changes from blue to red. Benefiting from the highly sensitive detection of ALP, the proposed plasmonic ELISA has achieved an ultralow detection limit (100 pg/mL) for human immunoglobulin G (IgG). Importantly, the visual detection limit (3.0 ng/mL) allows the rapid differential diagnosis with the naked eye. The further detection of human IgG in fetal bovine serum indicates its applicability to the determination of low abundance protein in complex biological samples.
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS , Yantai Shandong 264003, P. R. China.|University of Chinese Academy of Sciences , Beijing 100049, P. R. China.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS , Yantai Shandong 264003, P. R. China.
authors.forename: Zhaopeng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS , Yantai Shandong 264003, P. R. China.|University of Chinese Academy of Sciences , Beijing 100049, P. R. China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Wang
authors.affiliation: Ocean School, Yantai University , Yantai 264005, P. R. China.
authors.forename: Fangbin
authors.initials: F
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS , Yantai Shandong 264003, P. R. China.
authors.forename: Lingxin
authors.initials: L
authors.lastname: Chen
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification*; D007455:Iodine / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*
chemical_list: D007074:Immunoglobulin G; D006046:Gold; D007455:Iodine; D000469:Alkaline Phosphatase
keywords: alkaline phosphatase; etching; gold nanorods; iodine; plasmonic ELISA