Channel-size enlarging strategy for liposome production scale-up: A simplified approach

The clinical translation of liposome-based nanomedicines is limited by the lack of scalable production methods ensuring precise control over particle size and homogeneity. While microfluidics offers a promising single-step solution for manufacturing liposomes with desired attributes, limited throughput remains the main constraint for its industrial-scale integration. Here we present a versatile fluidic system utilizing simple and commercially available T-shaped mixers for scalable production of highly monodisperse liposomes, ranging from few mL/min to 30 L/h of Total Flow Rate (TFR). Firstly, to characterize the platform, the influence of TFR and diverse flow regimes on size and Polidispersity Index (PDI) of empty-Doxil® liposomes was investigated. Notably, particle homogeneity and reproducibility progressively improved with the transition from laminar to turbulent regimes. To enhance system throughput, the inner channels of the mixer were enlarged and TFRs increased while testing fixed Reynolds numbers (Re), hence ensuring similar flow conditions across scales. This approach yielded consistent liposome dimensional features, confirming Re as a reliable scalability factor. An empirical correlation between Re, particle size and PDI was also derived. Furthermore, our large-scale setup was successfully employed for preparing unilamellar 80 nm Doxil® liposomes then loaded with Doxorubicin, as confirmed by Cryo-TEM analysis. This scaling approach was also applied to empty Marqibo® and DOTAP nanoparticles, achieving consistent results across scales. Our findings point out the scalability, efficiency and adaptability of this strategy, bridging the gap between laboratory innovation and industrial implementation and offering practical insights into liposome engineering through fluidic control.