title: Surface-enhanced Raman scattering for immunoassay based on the biocatalytic production of silver nanoparticles.
abstract: We have reported on a novel enzyme immunoassay method for the detection of protein using biocatalytic silver nanoparticles as an enhanced substrate based on surface-enhanced Raman scattering (SERS). First, ascorbic acid was converted from ascorbic acid 2-phosphate by alkaline phosphatase immobilized on polystyrene microwells after a typical sandwich immunoreaction. Then Ag(I) ions were reduced to silver nanoparticles by the obtained ascorbic acid, which would result in a SERS signal when Raman dyes were absorbed. Using human IgG as a model protein, a wide linear dynamic range (1 to 100 ng ml(-1)) was reached with a low detection limit (0.02 ng ml(-1)) under the optimized assay conditions. Moreover, the production of an enhanced substrate was chosen as the signaling element in this method, which demonstrates a new way for SERS-based quantitative detection. These results suggest that the application of SERS enhanced by biocatalytic production of metal nanopaticles holds a promising potential for a sensitive immunoassay.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Luo
authors.forename: Yi
authors.initials: Y
authors.lastname: Liang
authors.forename: Jianhui
authors.initials: J
authors.lastname: Jiang
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D055162:Biocatalysis; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis; D053768:Metal Nanoparticles / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D004800:Enzymes, Immobilized; D007074:Immunoglobulin G; D011137:Polystyrenes; C011669:ascorbate-2-phosphate; D012834:Silver; D000469:Alkaline Phosphatase; D001205:Ascorbic Acid