Evaluating Flow-Focused Microfluidic Device Fabrication Techniques for Silk Fibroin Microgel Production

This study systematically compared three microfluidic device fabrication methods—maskless photolithography, laser engraving, and 3D printing—for the generation of photo-crosslinked silk fibroin microgels. Using a Ru/SPS visible-light crosslinking system, silk droplets were formed in flow-focusing PDMS devices and photocrosslinked to form spherical or rod-shaped microgels. Fabrication precision, droplet generation rates, and resulting microgel size distributions were characterized. Microgel stiffness was tunable from ~40 kPa to ~590 kPa by varying silk molecular weight (controlled via degumming time). The results demonstrate the trade-offs between fabrication accessibility, channel smoothness, and output reproducibility, highlighting low-cost pathways for scalable microgel production in tissue engineering applications.