Development of a Simple ELISA System Using a Jungle Gym Structure as an Antibody-Immobilization Substrate

Abstract

The performance of a compact fluorometer using a commercially available 1-cm pathlength cuvettes as a sample cell was evaluated from measurements of fluorescence intensity of resorufin. The detection limit (3σ) and relative standard deviation (RSD, n = 3) were 2.4 × 10² pM and less than 2.1 %, respectively. These indicate that the fluorometer can measure with high sensitivity and high accuracy despite its small size. We developed an ELISA method using a jungle gym structure (JGS). C-reactive protein (CRP) is used as a biomarker model for practical biomarker measurement in the medical field. A large specific surface area of JGS enable us to capture many CRP molecules, leading to facilitation of the enzymatic reaction. The detection limit (3σ) and RSD (n = 3) of CRP in this method were 50 pg mL⁻¹ and 8.5∼17 %, respectively, indicating that this method has almost same performance as the ELISA method using a fluorescent microplate reader. Advantages of our system, i.e., high sensitivity and a simple operation, have a potential for the measurement of various biomarkers in Small and medium-sized medical facilities.