The Dissolvable Alginate Fiber Network Produced via the Immersed Microfluidic Spinning

Pore size and pore interconnectivity that characterize the topology of the vascular networks in tissue constructs are critical to healthy cell behavior and tissue formation. While scaffolds with hollow channel structures have gained significant attention, still creating the hollow channel networks within various cellular matrices such as cell-laden hydrogels, remain a slow process limited by the speed of material extrusion of 3D printing techniques for the deposition of sacrificial fibers. To address the issue of low throughput for sacrificial fiber production and placement, we propose to utilize the micromanufacturing technique of the immersed microfluidic spinning. Present study discusses the optimization of the topology of the sacrificial calcium alginate microfibers as a function of alginate concentration and the gauge of the needle used in the immersed fluidic spinning. An important parameter of the fabricated fiber network is the size of the loops produced via this method. We demonstrate that the loops with radii between approximately 1,600 and 3,200 microns can be produced with needle of 30 gauge for alginate concentrations between 1% and 8%. Fiber diameters are also characterized as a function of needle gauge and alginate concentration. Finally, viability of the fibroblast cells in GelMA are qualitatively studied as a function of the distance of the cells from the outside boundary of the gel (where the cell media is located). As expected, the cell viability falls as the distance from the outer boundary of the gel increases.