Validation of an Inertial Microfluidic Isolation System for Liquid Biopsy

Liquid biopsy is a critical tool for understanding cancer metastasis and monitoring disease progression. Circulating tumor cells (CTCs) obtained from liquid biopsy samples provide essential information on disease progression in most solid tumors. Consequently, isolating and analyzing CTCs is vital to enhance our understanding of disease progression, assess interventions, and improve clinical outcomes in cancer patients. However, CTCs are exceptionally rare and difficult to isolate from blood, making them challenging to acquire and investigate. The rarity of CTCs is a consequence of both the nature of metastasis and the technical limitations of available isolation strategies. Commercial isolation systems use immunomagnetic techniques that rely on expensive antibodies and have low sensitivity and recovery rates due to heterogeneous expression of cellular surface markers. To address these issues, inertial microfluidic systems were developed to improve cell separation recovery and efficiency. These systems do not rely on surface marker detection but instead exploit inertial forces and the differential sizes of cells to separate CTCs from blood. In this work, we validate and assess the performance of a co-flow inertial microfluidic device for cell separation, focusing on its efficiency, purity, and recovery rate using murine metastatic breast cancer models. Additionally, we benchmarked the enhanced performance of the inertial microfluidic device against a commercial immunomagnetic separation system by isolating endogenous CTCs from pancreatic cancer patient blood. Finally, to further understand CTC behavior, we conducted in vitro analyses of pancreatic CTCs to investigate cancer cell phenotype and migration behavior under treatment.