Upscaling the Fabrication of Rod-Shaped Microgels: A Microfluidic Method Combining Step-Emulsification With Consecutive Droplet Confinement in Parallelized Microchannels.

Anisometric rod-shaped microgels are an emerging material class holding potential for tissue engineering. Their anisotropic shape has proven advantageous in the fabrication of granular hydrogels and microporous annealed particle scaffolds (MAPs), featuring larger pore sizes in comparison to their spherical counterparts. However, to enable the use of rod-shaped microgels as building blocks for high-throughput tissue models, a robust and scalable production method is needed. Here, we report a microfluidic fabrication method to produce rod-shaped microgels by combining step-emulsification (SE) and droplet confinement. We highlight the development of the microfluidic chip design, and characterize the properties of the microgel rods produced via on-chip gelation, using two light-induced polymerization chemistries. Compared to single-channel microfluidic techniques, rod-shaped microgels are generated in eight parallelized microchannels in a relevant size range for tissue engineering applications, holding potential for further upscaling.