Magnetic Polystyrene Nanoparticles Prepared by Emulsion Solvent-Evaporation for the Chemiluminescent Immunoassay

In clinical diagnosis, magnetic polystyrene nanoparticles (MPS NPs) are commonly applied to, e.g., the chemiluminescent immunoassay (CLEIA). However, the conventional preparation method of MPS NPs requires a long duration of heating to form polymer particles, which is inefficient. In this study, we prepared MPS NPs by emulsion solvent-evaporation without heating. We evaluated the effect of the solvent in the water and organic phases on the magnetic particle content. MPS NPs prepared by 4% (v/v) MeOH aqueous solution and adding stearic acid (SA) (4MeSA–MPS NPs) exhibited the highest magnetic particle content. Furthermore, CLEIA analysis indicates that the C-reactive protein detection limit is 80 pg/mL. Thus, 4MeSA–MPS NPs are promising for clinical diagnoses.