Spectroscopically Encoded Microspheres for Antigen Biosensing

Here, we demonstrate the potential of barcoded resins (BCRs) as a reliable platform for immunoassays. Four BCRs were synthesized by dispersion polymerization of 4-methylstyrene, t-butylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene. Methacrylic acid was included in the polymerization step to provide an anchor point for antibody conjugation. In addition to identifying the BCRs through their unique spectrum in an immunoassay experiment, Raman scattering spectroscopy confirmed the immunoreactivity of the bead-conjugated antibody by detecting 150 ng/mL (∼150 pg/bead) of fluorescently labeled rabbit IgG antigen. The simplicity, versatility, and effectiveness of this platform demonstrate its potential for high-throughput multiplexed bioassays.