Fig. 2

Microfluidic systems for tumor spheroid culturing. a A microfluidic device that utilizes hydrodynamics to guide cancer cells into U-shaped traps and form tumor spheroids. This method highlights the controllability over the number of cells in each spheroid, the ability to sustain long-term culturing, and on-chip drug testing, which are features not present in conventional methods [149]. b A tumor spheroid culturing device that combines microfluidic principles and cell suspension techniques. The cell suspension injected through the PDMS channel was gathered in the pyramid-like holes to be aggregated. The device supports spheroid formation and long-term culture [150]