The Development of Fibers That Mimic the Core-Sheath and Spindle-Knot Morphology of Artificial Silk Using Microfluidic Devices

Spider and silkworm produce diverse silk fibers from spinning dopes through smart spinnerets. Spider's capture silk is composed of core thread and periodic spindle-knots, while silkworm silk consists of fibroin core and sericin outer layer. To mimic the morphologies of natural heterostructured silks, artificial fibers are dry-spun using a multichannel microfluidic chip, served with a highly viscous core solution of regenerated silk fibroin and low viscosity sheath solution of sericin. Silk fibers with core-sheath, groove, and spindle-knot structures are obtained by controlling the flow rates and viscosities of the two microfluids depending on the laminar flow, Kelvin-Helmholtz instability, or Plateau-Rayleigh instability.