Lymphoma cell isolation using multifunctional magnetic nanoparticles: antibody conjugation and characterization

The early detection of B-cell lymphoma and non-Hodgkin's lymphoma has a wide impact on the diagnosis and therapy of lymphoma patients. Capturing and sorting tumour cells with magnetic nanoparticles (MNPs) has received considerable attention in recent years. Despite these successes, the efficient isolation of circulating tumour cells from complex biological fluids is still under development for the early diagnosis of lymphoma. In this study, MNPs are functionalized with anti-CD20 antibodies using an avidin-biotin linkage, with the aim of achieving specific cancer cell detection and efficient isolation. Anti-CD20 antibody-conjugated MNPs (Ab MNPs) could specifically target CD20-expressing lymphoma cells. The capture efficiency of the Ab MNPs in the lymphoma cell line was >95% with regard to the mixture of two cell lines, as confirmed by flow cytometry and confocal microscopy. Transmission electron microscopy confirmed that the conjugation of an antibody with the MNPs increased the size from 12 to 47 nm. The surface charge of the Ab MNPs was examined by using zeta potential measurements. Furthermore, Prussian blue staining was performed to confirm the interaction of Ab MNPs with the targeted lymphoma cells. Our results indicated that the receptor recognition ability of the antibody was fully retained after conjugation with MNPs. In conclusion, anti-CD20 MNPs can be used for very sensitive detection and quick isolation of CD20-positive lymphoma cells among mixed cells by using only a permanent magnet.