An ultra-compact acoustofluidic device based on the narrow-path travelling surface acoustic wave (np-TSAW) for label-free isolation of living circulating tumor cells.

Obtaining highly purified intact living cells from complex environments has been a challenge, such as the isolation of circulating tumor cells (CTCs) from blood. In this work, we demonstrated an acoustic-based ultra-compact device for cell sorting, with a chip size of less than 2 × 1.5 cm. This single actuator device allows non-invasive and label-free isolation of living cells, offering greater flexibility and applicability. The device performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with cancer cells. Using the narrow-path travelling surface acoustic wave (np-TSAW), precise isolation of 10 μm particles from a complex mixture of particles (5, 10, 20 μm) and separation of 8 μm and 10 μm particles was achieved. The purified collection of 10 μm particles with high separation efficiency (98.75%) and high purity (98.1%) was achieved by optimizing the input voltage. Further, we investigated the isolation and purification of CTCs (MCF-7, human breast cancer cells) from blood cells with isolation efficiency exceeding 98% and purity reaching 93%. Viabilities of the CTCs harvested from target-outlet were all higher than 97% after culturing for 24, 48, and 72 h, showing good proliferation ability. This novel ultra-miniaturized microfluidic chip demonstrates the ability to sorting cells with high-purity and label-free, providing an attractive miniaturized system alternative to traditional sorting methods.