[12a-A408-1~12] 12.7 Biomedical Engineering and Biochips

[12a-A408-1] Electrochemiluminescent method using gold nanoparticles catalyst for digital baiosensing

〇Kohei Nagano^1,2, Wilfred Espulgar¹, Hiroyuki Yoshikawa¹, Masato Saito^1,2, Eiichi Tamiya^1,2 (1.Graduate School of Engineering Osaka Univ., 2.PhotoBIO Lab. AIST-Osaka Univ)

Keywords:electrochemiluminescence, biosensing

Electrochemiluminescence (ECL) method is attractive in terms of high sensitivity and low background. In ELISA method, ECL sensor uses antibody as recognition element and utilize enzyme reaction as enhancer of ECL, but in this study, we use new enzyme-like catalytic reaction of gold nanoparticle (AuNP) instead of enzyme. New catalytic reaction of AuNP produces hydrogen peroxide from dissolved oxygen in presence of amine. We can utilize this reaction for ECL measurement because hydrogen peroxide enhances ECL intensity of luminol. AuNP can be modified with antibody easily and more resistant to pH change and high temperature than enzyme, so it’s expected for this method to be simpler and more stable ECL measurement. In addition, we fabricate the electrode which has a lot of microwells above anode and cathode, and conduct this ECL measurement in microwells. If the AuNP concentration is the same, the smaller sample solution is, the fewer AuNPs exist. When sample volume is small enough, we can obtain ECL signal from just one AuNP theoretically. In that case, the number of AuNP can be directly counted from the presence or absence of light emission from each well, and concentration of target substance can be calculated without calibration curve. We define this sensing method as “digital sensing”. In this study, we try to obtain ECL signal from smaller sample volume and fewer AuNPs for digital sensing.