Gradient Magnetic Separation and Fluorescent Imaging‐Based Heterogeneous Circulating Tumor Cell Subpopulations Assay with Biomimetic Multifunctional Nanoprobes

Abstract The heterogeneity of circulating tumor cells (CTCs) greatly impacts cancer metastasis and malignancy, contributing to increased mortality. Therefore, the analysis of such heterogeneity is essential to clinical diagnosis, treatment, and monitoring of patients. Though varied, the types and expression levels of proteins on heterogeneous CTCs enable specific recognition and separation. Accordingly, herein the sequential magnetic separation and fluorescence visualization‐based assay of heterogeneous CTCs after the model tumor cells of BT474 Her2+++ , LNCaP PSMA++ , and MDA‐MB‐231 Vim+ binding with corresponding antibody‐modified biomimetic fluorescent‐magnetic nanoprobes with different magnetic sensitivities is reported. These nanoprobes‐bound cell subpopulations are specifically recognized and magnetically separated at different time points under an external magnetic field with good capture performance within several minutes. Moreover, a low detection limit of 1 cell mL −1 in blood sample could be achieved. Consequently, the as‐proposed strategy based on gradient magnetic separation, fluorescent imaging, and biomimetic membrane, shows promise for clinical applications.