Integration of Lateral Filter Arrays with Immunoaffinity for Circulating Tumor Cell Isolation

Circulating tumor cells (CTCs) are considered an important biomarker for cancer prognosis and treatment monitoring. A variety of methods have been employed to isolate a small number of CTCs from billions of normal blood cells. These methods are generally based on either physical (e.g. size) or biological properties (e.g. immunoaffinity) of CTCs. However, the heterogeneity of CTCs in both physical and biological properties limits the efficiency of various approaches for CTC isolation. To address this challenge, we have developed a lateral filter array microfluidic (LFAM) device to integrate size‐based separation with immunoaffinity‐based CTC isolation. LFAM consists of a serpentine main channel for the majority of a sample passing by and an array of lateral filters for CTC isolation. The unique device design produces a two‐dimensional flow, which reduces nonspecific geometric capture of normal cells as typically observed in vertical filters. LFAM is further functionalized by immobilizing antibodies that are specific to the target cells. The resultant LFAM devices show capture efficiency of 98.7±1.2% for pancreatic cancer cells (L3.6pl) spiked in blood samples. LFAM also demonstrates better performance than a previously reported immunoaffinity‐based micromixer device when both devices are compared for isolating CTCs from patients with metastatic colorectal cancer, indicating its potential for clinical applications.