Multi-targeting magnetic hyaluronan capsules efficiently capturing circulating tumor cells

Accurate detection and isolation of circulating tumor cells (CTCs) hold high value for urgent clinical applications in cancer prognosis and treatment monitoring. Even though the immuno-magnetic isolation strategy has been an important milestone for enrichment of precious CTCs from complex clinical samples, the origin and cell cycle change of CTCs would influence greatly on the performance of antibody-mediated capture process. Herein, we proposed the multi-targeting magnetic capsules (TMCs), which combine the natural immune recognition and tumor-specific ligand targeting, for the purpose of rare CTCs capture. Generally, the fluorescence-visible magnetic capsules (MCs) were constructed via an ultra-sonication assembly procedure using fluorescently-labeled thiolated hyaluronan (RhB-HA-SH) and hydrophobic Fe₃O₄ nanoparticles, during which superparamagnetic Fe₃O₄ were blocked by RhB-HA-SH cross-linking via oxidation of the thiol groups. Functionalized with folic acid (FA) and anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody, the obtained fluorescent-visible multi-targeting hyaluronan magnetic capsules could capture and isolate more than 88% of rare MCF-7 cells in mimic biological samples in 15 min of incubation. Moreover, these isolated cells still showed good proliferation and migration abilities, facilitating further CTCs-related studies. Furthermore, these TMCs were successfully employed to the capture and detection of few CTCs in 1.5 mL cancer patient peripheral blood samples, indicating that they could be a promising candidate for CTCs capture and detection through simple and fast magnetic manipulation.