Isolation and Analysis of Tumor Cell Subpopulations Using Biomimetic Immuno‐Fluorescent Magnetic Multifunctional Nanoprobes

Abstract Tumor cell heterogeneity leads to differences in tumor proliferation and invasiveness, as well as drug sensitivity. These factors affect the diagnosis, treatment, and monitoring of tumor progression. Thus, analysis of tumor cell subpopulations is crucial for tumor diagnosis and individualized treatment. This study describes an approach to capture and sequentially isolate tumor cells subpopulations based on antibody‐mediated recognition and magnetic gradient separation, using biomimetic immuno‐fluorescent magnetic multifunctional nanoprobes, consisting of magnetic γ‐Fe 2 O 3 and fluorescent quantum dots as the core, and leukocyte membrane vesicles with antibodies as the shell. Upon binding with leukocyte membrane‐coated fluorescent magnetic nanoparticles with antibodies (LFMNPs‐Ab), the model of three types of breast cancer cells with different expression levels of Her2 marker on the cell surface, namely, BT474 Her2+++ , MDA‐MB‐453 Her2++ , and MDA‐MB‐231 Her2+ , develop different magnetic susceptibilities. Based on the differences in their magnetic response under constant external magnetic field, the three tumor cell subpopulations in blood samples are magnetically separated and collected sequentially at 90, 120, and 180 s, respectively, as confirmed by a subsequent fluorescent imaging assay. The magnetic gradient separation‐based strategy described in the present study is a simple, fast, and feasible method for targeted separation of tumor cell subpopulations, and shows great potential for clinical study.