Tuning the Properties of Wet-Spun SA/GelMA Fiber-Like Microgels Through Processing and Polymer Composition

Abstract

Microgels offer modular building blocks for injectable and biofabricated materials, yet tuning their geometry and internal physicochemical properties remains challenging, particularly for anisotropic architectures. Here, we investigate a wet-spinning strategy for fabricating fiber-like sodium alginate/gelatin methacryloyl (SA/GelMA) microgels and systematically examine the respective contributions of processing conditions and polymer composition to their structural and rheological properties. Variation of needle size and extrusion flow rate showed that macroscopic fiber geometry was governed predominantly by hydrodynamic processing conditions, with smaller needle diameters and higher flow rates producing thinner fibers. In contrast, polymer composition exerted a stronger influence on internal microporous structure and rheological behavior, with increasing SA content generally promoting denser microstructures and more elastic, shear-thinning responses. Needle size also introduced secondary effects on microstructure and rheology, indicating that processing and material parameters are not completely independent but contribute differently to the resulting properties. These findings provide practical guidance for tuning the geometry, internal architecture, and bulk rheological behavior of anisotropic SA/GelMA hydrogel microstructures through processing and polymer composition, supporting their subsequent use in granular hydrogel and biofabrication systems.