In the present work, we report on an enzyme-free electrochemiluminescent (ECL) immunosensing scheme utilizing the catalytic generation of reactive oxygen species (ROS) from gold nanoparticles (AuNPs) (diameter ≥5 nm) dispersed in aqueous solutions of trishydroxymethylaminomethane (Tris). First, to examine this catalytic pathway in detail, the effects of various factors such as the AuNP size and concentration, dispersant type and concentration, and dissolved oxygen were investigated using the electrochemiluminescence (ECL) of luminol. It was found that the catalytic generation of ROS from AuNPs can be regulated chemically by altering conditions such as the type, concentration, and pH of the solution that the AuNPs are dispersed in. Under the best conditions studied in this work, the AuNPs displayed high catalytic activity toward ROS generation, with an estimated apparent turnover number per AuNP of 0.1 s, comparable to those of several common peroxide-producing enzymes. Following these studies, this phenomenon was applied to develop a one-step enzyme-free ECL immunosensor based on sandwiching the target analyte using antibody-conjugated magnetic beads (MB) and AuNPs. Using IgA as a model analyte, the developed immunosensor was able to detect the target in the range of 1 ng/mL to 10 μg/mL, with the lower detection limit being comparable to those of commercial assays for the same target. Altering the antibodies used to modify the MB and AuNPs could further improve the detection limit as well as expand the applicability of this immunoassay to the detection of other analytes.

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Electrochemiluminescence (ECL) has been a useful analytical tool for fields such as molecular biology, food analysis, and analytical chemistry. In situ generation of reactive oxygen species (ROS) by surface mediated catalysis works collaboratively with the luminol based ECL system. This work describes an ECL strategy involving in situ ROS generation from the surface of gold nanoparticles (AuNP). We reported on a novel condition to induce AuNP catalysis, and examined the application of this phenomenon to an immunosensing platform based on AuNP catalysis and ECL.

Excess generation of reactive oxygen species (ROS) could trigger a number of human diseases. We focused that antioxidants in beverages suppress the effect of ROS. Electrochemiluminescence (ECL) was determined by newly designed bi-potential screen printed electrodes and electron multiplying charge coupled device (EM-CCD) camera. Luminol based ECL was quenched due to the consumption of ROS by the antioxidants. Rapid and sensitive detection of antioxidants such as ascorbic acid and chlorogenic acid were demonstrated in beverage samples.

An alginate fuel cell comprising a TiO2-modified carbon sheet (TiO2/C) anode was developed. The power output of the fuel cell and decomposition of alginate were enhanced by solar irradiation of the anode.