An efficient method for preparing high-performance multifunctional polymer beads simultaneously incorporated with magnetic nanoparticles and quantum dots

An efficient modified method combining conventional swelling method with high-temperature swelling method was applied to prepare high-stable multifunctional MNPs-QD-encoded polystyrene beads simultaneously with large encoding capacity and fast separation. In this paper, the results demonstrate that encapsulating QDs into pre-prepared MNPs-beads is the best sequence, which keeps high brightness and fast separation. The MNPs-QD-encoded microcarriers designed by our proposed method exhibit excellent performance for magnetic manipulation and optical encoding. What is more, they also have better physical and chemical stabilities. Compared with beads prepared via conventional swelling method, the leakage of nanoparticles from the designed MNPs-QD-encoded poly (styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) induced by organic solvents (e.g.cyclohexane) is less than 6%; meanwhile, fluorescence intensity of MNPs-QDs-encoded PSEMBs fluctuates slightly more in a wide range of pH 2–12 buffers. In addition, immunoassay performance for human IgG detections indicates that carboxyl groups on fluorescent microsphere surface facilitate efficient attachment of biomolecule and therefore they can be further applied to fast separation and multiplexed biomolecular assays.