Gravity-Oriented Microfluidic Device for Biocompatible End-to-End Fabrication of Cell-Laden Microgels.

Droplet microfluidics are extensively utilized to generate monodisperse cell-laden microgels in biomedical applications. However, maintaining cell viability is still challenging due to overexposure to harsh conditions in subsequent procedures that recover the microgels from the oil phase. Here, a gravity-oriented microfluidic device for end-to-end fabrication of cell-laden microgels is reported, which integrates dispersion, gelation, and extraction into a continuous workflow. This innovative on-chip extraction, driven by native buoyancy and kinetically facilitated by pseudosurfactant, exhibits 100% retrieval efficiency for microgels with a wide range of sizes and stiffnesses. The viability of encapsulated cells is perfectly maintained at approximate to 98% with minimal variations within and between batches. The end-to-end fabrication remarkably enhances the biocompatibility and practicality of microfluidics-based cell encapsulation and is promising to be compatible with various applications ranging from single-cell analysis to clinical therapy. End-to-end fabrication of microgels, including uniform dispersion, homogeneous gelation, and continuous extraction, is realized in a gravity-oriented microfluidic device. Microgels extraction is achieved by buoyancy guidance and pseudosurfactant-induced acceleration, which is applicable to microgels down to 15 mu m in diameter and of varying stiffness. This method maintains excellent cell viability with minimal variations, enhancing the practicality of microfluidics-based cell encapsulation. image