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1,4-Benzenediboronic-Acid-Induced Aggregation of Gold Nanoparticles: Application to Hydrogen Peroxide Detection and Biotin–Avidin-Mediated Immunoassay with Naked-Eye Detection

Yang, Ya-Chun, Tseng, Wei-Lung
Analytical chemistry 2016 v.88 no.10 pp. 5355-5362
antibodies, antigens, citrates, colorimetry, glucose, glucose oxidase, humans, hydrogen peroxide, immunoassays, immunoglobulin G, nanogold, oxidation, phenol, rabbits, systems engineering
Hydrogen-peroxide (H₂O₂)-induced growth of small-sized gold nanoparticles (AuNPs) is often implemented for H₂O₂ sensing and plasmonic immunoassay. In contrast, there is little-to-no information in the literature regarding the application of H₂O₂-inhibited aggregation of citrate-capped AuNPs. This study discloses that benzene-1,4-diboronic acid (BDBA) was effective in driving the aggregation of citrate-capped AuNPs through an interaction between α-hydroxycarboxylate of citrate and boronic acids of BDBA. The H₂O₂-mediated oxidation of BDBA resulted in the conversion of boronic acid groups to phenol groups. The oxidized BDBA was incapable of triggering the aggregation of citrate-capped AuNPs. Thus, the presence of H₂O₂ prohibited BDBA-induced aggregation of citrate-capped AuNPs. The BDBA-induced aggregation of citrate-capped AuNPs can be paired with the glucose oxidase (GOx)–glucose system to design a colorimetric probe for glucose. Moreover, a H₂O₂·BDBA·AuNP probe was integrated with sandwich immunoassay, biotinylated antibody, and avidin-conjugated GOx for the selective naked-eye detection of rabbit immunoglobulin G (IgG) and human-prostate-specific antigen (PSA). The lowest detectable concentrations of rabbit IgG and human PSA by the naked eye were down to 0.1 and 4 ng/mL, respectively. More importantly, the proposed plasmonic immunoassay allowed the naked-eye quantification of 0–10 ng/mL PSA at an interval of 2 ng/mL in plasma samples.