Plug-and-play microfluidic production of monodisperse giant unilamellar vesicles using droplet transfer across Water-Oil interface

Giant unilamellar vesicles (GUVs) are cell-sized compartments widely used in biological and chemical applications. The monodispersity of GUVs is essential for quantitative analysis and experimental reproducibility in biomimetic microreactor studies. In this study, we established a highly reproducible plug-and-play microfluidics-based method to generate monodisperse GUVs without surface treatment of the channel or precise flow-rate adjustment. In the microfluidic channel, we generated water-in-oil (W/O) droplets through hydrodynamic flow focusing and transferred across the W-O interface to form thin-shelled water-in-oil-in-water (W/O/W) droplets as precursors to GUVs. The success rate of the W/O droplet transfer reached nearly 100% by stabilizing the co-flow of oil and water and adjusting the curvature of the W-O interface. Owing to interfacial energy minimization, the thin oil layer of the W/O/W droplets dewetted and detached to form GUVs. We performed a membrane-protein insertion assay to confirm the unilamellarity of the GUVs and their shrinkage caused by osmotic action.

Automated summary

In this study, a highly reproducible microfluidics-based method was established to generate monodisperse giant unilamellar vesicles (GUVs) without surface treatment or precise flow-rate adjustment. The success rate of GUV formation reached nearly 100% by stabilizing the oil-water co-flow and adjusting the curvature of the interface. Membrane-protein insertion assay confirmed the unilamellarity of GUVs and their shrinkage caused by osmosis.