Characterization of dextran-coated magnetic nanoparticles (Fe3O4) conjugated with monoclonal antibody through low gradient magnet and centrifugation-based buffer separation processes

Conjugation of magnetic nanoparticles (MNPs) with biomolecules can be achieved through covalent or non-covalent bonding and chemisorption. By glutaraldehyde cross-linking, we successfully conjugated mouse monoclonal antibody (Ab) with amine-functionalized dextran-coated MNPs of diameter 50 nm. We aim to characterize the antibody-conjugated MNPs (Ab-MNPs) after buffer separation through low-gradient magnet and centrifugation. The magnetic separation/washing was achieved throughout the conjugation process by attaching the MNPs solution to a natural magnet for about 12 h. The centrifugation-based separation steps were done at 15,000xg for 30 min. The transmission electron microscope (TEM) data showed the flower-shaped core MNPs and their increased diameter after conjugation with Abs. The nanoparticle tracking analysis (NTA) also revealed the size distribution and drift velocities in MNPs and Ab-MNPs. The size distribution and concentration data showed an increased size and a lower value after conjugation, respectively. The drift velocities of Ab-MNPs prepared by the centrifugation method were significantly reduced than magnetic separation and standard MNPs.

Automated summary

Conjugation of magnetic nanoparticles (MNPs) with biomolecules can be achieved through covalent or non-covalent bonding and chemisorption. In this study, we successfully conjugated mouse monoclonal antibody (Ab) with amine-functionalized dextran-coated MNPs by glutaraldehyde cross-linking. The characterization of the antibody-conjugated MNPs (Ab-MNPs) was conducted through buffer separation using low-gradient magnet and centrifugation.