Achieving passive microparticle filtration with micropore membranes is challenging due to the capillary pinning effect. Inspired by the teapot effect, the authors propose a tap-triggered self-wetting strategy using a 3D-printed polymer tap-trigger microstructure to lower the micropore membrane gating threshold. This resulted in a 35-60 fold reduction in the threshold pressure. A 3D cone-shaped cell sieve incorporating this microstructure achieved a high throughput (above 20 mL/min) while filtering leukocytes from whole blood with comparable purity, higher platelet removal, and lower leukocyte simulation, suitable for single-cell analysis. The tap-triggered self-wetting strategy significantly improved passive microparticle filtration performance.
