Taming Fluids: 3D Precision Manipulation Enabled by Smart Bamboo Baskets

Conventionally, the notion of “fetching water with a bamboo basket” has served as a metaphor for impracticality due to interfacial instability. We present a transformative approach: a programmable polyhedral frame system governed by capillary forces, which shifts the paradigm from uncontrollable to precisely designed fluidic interfaces. The magnetic-actuated capillary container, incorporating steel beads and a 3D polyhedral frame, enables the construction of predefined fluid interfaces in air, water, and oil, allowing for sophisticated manipulations including translation, rotation, and flipping. Through interfacial gelation, we fabricate freestanding 3D membranes capable of pH-responsive release, as demonstrated with vitamin B₂. By interconnecting these frames via single or double rods, we achieve controlled liquid continuity, forming a reconfigurable “programmable bamboo basket array” that can reversibly capture and release liquids. This system supports 3D multi-fluid patterning, spatiotemporally controlled drug release, and bacterial encapsulation. Furthermore, the open fluid network uses polyhedral frames as chambers and connecting rods as valves, driving continuous flow without external pumping, transforming open architecture into an advantage for interfacial engineering: free interfaces support fluid inflow and outflow as well as reaction regulation, while increased interfacial areas enhance mass and heat transfer. Uniting structural design with capillary programming, this system enables precise 3D fluid manipulation and opens new pathways in open microfluidics and interfacial chemistry, with applications spanning micro-nanofabrication to biomedicine.