Rapid Concentration-Dependent Liposome Size Profiling Using a Cascaded and Concentration-Encoded Microfluidic Platform

Controlling the size of lipid-based nanomedicines is crucial for the in vivo drug delivery efficiency. Many microfluidic devices have been devoted to optimizing liposome size by adjusting the total flow rate (TFR) and flow rate ratio (FRR). However, existing microfluidic devices have difficulty comprehensively evaluating the influence of lipid concentration and fluid parameters on liposome size. Here, we developed a cascaded and concentration-encoded microfluidic platform (CCEMP) for high-throughput evaluation of lipid concentration effects on liposome size. The CCEMP consists of a microfluidic concentration gradient generator (MCGG) and a microfluidic liposome generator (MLG), enabling parallel screening of six lipid concentrations with 6-fold higher throughput than single-channel devices. To validate the biological significance of precise size tuning, we synthesized various drug-loaded liposomes using the CCEMP. In vitro and in vivo evaluations revealed that the CCEMP-optimized small-size liposomes exhibited superior cellular uptake and tumor accumulation compared to larger counterparts. This modular microfluidic device provides outstanding flexibility for accelerating formulation development and tailoring liposomal properties for enhanced delivery efficiency and therapeutic capacity.