Rapid and Controlled Transition of Magnetic Nano- to Micro-particles: A Useful Feature for Bioseparations

摘要

For solution-based immunoassays and bioseparations, magnetic nanoparticles have many potential advantages over commonly used magnetic microbeads. These advantages are due to high surface area to volume ratio, favorable diffusion coefficients, and better access to targets in sterically constrained environments. However, magnetic nanoparticles have poor magnetophoretic mobility, and they do not separate with simple magnets. Stimuli-responsive mNPs can circumvent this problem. These mNPs are stable colloids for rapid diffusion and binding at one condition but an appropriate stimulus causes them to transition to micron-sized, hydrophobic aggregates for easy separation. This work describes the development and characterization of stimuli-responsive mNPs. To demonstrate their utility in bioseparation assays, these mNPs are combined with similarly stimuli-responsive antibodies to isolate antigens from human serum samples.