Separation of Macrophages Using a Dielectrophoresis-Based Microfluidic Device

Macrophages are an important component of the immune system and play a key role in tissue damage repair and immune defense. As a potential biomarker, macrophages contribute to the early diagnosis and therapy of cancer and other disease. The isolation of macrophages is a key step in relevant research and clinical applications. However, conventional macrophage separation and purification methods rely on benchtop equipment and are time-consuming, inefficient, complicated, and immobile. Herein, we present a method based on dielectrophoresis (DEP) to rapidly separate and purify macrophages from micro-volume samples using a microfluidic device for liquid biopsy and point-of-care testing (POCT). The device can be mechanically manipulated easily for straightforward separation. The DEP force on macrophages was measured under different electric field conditions, then the macrophages were successfully separated from the mixture of macrophages (RAW264.7) and breast cancer cells (MCF-7) using the microfluidic chip. The purity of macrophages in the collections reached higher than 99%. The effects of flow rate and voltage on the separation efficiency of macrophages by DEP were further studied to optimize the separation conditions. This work proposes a new method for rapid separation of macrophages based on microfluidic systems, providing a technical foundation for macrophage-based disease monitoring and real-time rapid diagnosis.