Dual-screen-printed electrode platform for simultaneous detection of IgG and IgM antibodies using magnetic beads...

This study uses a dual-screen-printed electrode platform to investigate the electrochemical behavior of magnetic platforms with varying sizes for sensitive detection of immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies. Magnetic beads of 500 nm and 1 μm in diameter were functionalized with amino ferrocene and the receptor-binding domain of the severe acute SARS-CoV-2 spike protein. The sensor utilized a dual screen-printed electrode (SPE) system with spatially separated working electrodes, each immobilized with either anti-IgG or anti-IgM capture antibodies. A bipotentiostat was employed to independently monitor the electrochemical signals from these two working electrodes. Following incubation with target antibodies within a concentration range of 0.1 μg/mL to 200 μg/mL, the magnetic bead complexes were captured on their respective electrodes, and simultaneous electrochemical measurements of both IgG and IgM were conducted. The sensor's performance was evaluated in both buffer solutions and a complex serum-like matrix. Results showed distinct and quantifiable electrochemical responses for IgG and IgM, with minimal interference between the analytes. While matrix effects were observed, the sensor demonstrated its potential for simultaneous detection of SARS-CoV-2 antibodies in complex biological samples.