Programmable Axial-Radial Multichannel Nickel Microtubes Fabricated by Core-Filament Jet Electrodeposition

Programmable hollow metallic microdevices with lateral outlets are attractive for distributed fluid handling, but integrating an axial lumen, side channels, and a sealed distal tip remains fabrication-intensive. Here, a core-filament jet electrodeposition (CF-JED) strategy combines segmented electrolyte-jet operation with sacrificial nylon-fiber templating to fabricate multichannel nickel microtubes. An 80 μm nylon core defines the axial lumen, whereas 50 μm transverse and helical fibers prescribe lateral channels. Interrupting the jet creates the in situ assembly interval for template placement; resumed localized electrodeposition encapsulates the fibers and can close the distal tip, and physical pull-out releases the channels without chemical dissolution or drilling. Stable growth was obtained at 2.5 mA with an axial growth rate of approximately 15 μm·min^-1. Micro-computed tomography revealed a 50 ± 5 μm radial channel and a 76 ± 6 μm axial lumen interconnected within the sealed-tip structure. SEM/EDS confirmed open lateral apertures and nickel-rich walls, while water-immersion gas testing provided qualitative evidence of channel interconnectivity. CF-JED therefore provides a template-defined route to programmable multichannel hollow-metal microstructures; direct liquid-flow, mechanical, and biological validation remain necessary for application-specific use.