Controlled self-assembly of microgels in microdroplets

Microgels with embedded distinct compartments are robust tools for creating different physiochemical scaffolding conditions by co-encapsulation of various cargoes. This work presents a robust, rapid, and low-cost approach for one-step fabrication of multicompartmental microgels using droplet-based microfluidic systems. After selective modification of microchannels wettability using a simple and reliable patterning approach, double emulsion (DE) droplets are generated with desired number, size and composition of internal precursor core droplets. Upon gelation, the microgels confined in each oil droplet self-assemble, followed by their rapid release from oil droplet. By tuning the droplet generation and crosslinking parameters, complex microgels with desired structure and composition are fabricated to demonstrate the potential of the method for flexible production of codded microgels. The DE approach applied here enables accurate confinement of target compartments, provides a clog-free on-chip gelation, and more importantly offers high biocompatibility due to rapid release of microgels from unfavorable reagents. Implementation of different hydrogels such as alginate, agarose, and gelatin methacryloyl further demonstrates the robustness of presented method which is not limited to a specific material or gelling condition. This method can provide new opportunities in many biomedical applications from tissue engineering to drug delivery and high-throughput multiplex bioanalysis.