Stochastic fiber templating for rapid generation of perfusable microchannels via immersed microfluidic spinning...

The fabrication of biomimetic tubular architectures within hydrogel-based tissue constructs remains a major barrier to advancing scalable tissue engineering and organoid systems. Here, we present a rapid and modular strategy for engineering hollow, perfusable channels within gelatin methacryloyl (GelMA) hydrogels using dissolvable calcium alginate fibers fabricated by an immersed microfluidic spinning method. This approach enables stochastic deposition of sacrificial fibers within a broad range of total construct sizes, creating tortuous and coiled architectures directly within soft hydrogel matrices. Upon UV crosslinking, the alginate fibers are dissolved using a cytocompatible calcium-chelator solution, yielding continuous, open cavities. Across a range of GelMA concentrations, the method produced stable channels compatible with cell-laden constructs. Viability assays with human dermal fibroblasts (HDF) confirmed >90% cell survival in regions adjacent to the channel within the diffusion limit, ranging from 700µm in the softest 5% GelMA to 70µm in the stiffest 15% GelMA, following fabrication and fiber dissolution. Furthermore, epithelial seeding of tortuous channels yielded perfusable structures with tight junctional function, demonstrating the method's potential to generate biologically relevant epithelial architectures. This accessible, equipment-light platform provides a versatile route for integrating microchannel networks into hydrogel systems for regenerative andin vitromodeling applications.