3D-Printing the Spinneret: A single-piece microfluidic platform for tunable hydrogel fiber fabrication

Abstract We describe a single-piece 3D-printed aqueous two-phase system (ATPS) spinneret that eliminates the glass capillaries, alignment steps, and bonding required in polydimethylsiloxane (PDMS)-glass devices, collapsing multi-step fabrication into one print. The printed geometry preserves the coaxial flow needed for forming hydrogel fibers, including Janus structures, maintaining full functionality while removing fabrication complexity.