Microengineered Multicomponent Hydrogel Fibers: Combining Polyelectrolyte Complexation and Microfluidics.

Fiber-based techniques hold great potential toward the development of structures that mimic the architecture of fibrous tissues, such as tendon. Microfluidics and polyelectrolyte complexation are among the most widely used techniques for the fabrication of fibrous structures. In this work, we combined both techniques to generate hydrogel fibers with a fibrillar-like structure. For this, either methacrylated hyaluronic acid (MA-HA) or chondroitin sulfate (MA-CS) were mixed with alginate (ALG), being all negatively charged polysaccharides, combined with chitosan (CHT), which is positively charged, and separately injected into a microfluidic device. Through a continuous injection into a coagulation bath and subsequent photo-cross-linking, we could obtain multicomponent hydrogel fibers, which exhibited smaller fibrils aligned in parallel, whenever CHT was present. The biological performance was assessed upon encapsulation and further culture of tendon cells. Overall, the reported process did not affect cell viability and cells were also able to maintain their main function of producing extracellular matrix up to 21 days in culture. In summary, we developed a novel class of photo-cross-linkable multicomponent hydrogel fibers than can act as bioactive modulators of cell behavior.