Continuous, Size-Based Purification of Virus-like Particles Using Electro-Viscoelastic Microfluidics

The modular assembly of protein nanoparticles has enabled the design of highly immunogenic and cross-protective viral vaccines. However, downstream translation is hampered by labor-intensive purification methods that lack the resolution needed to efficiently sort molecular assemblies. Here, we report an affinity tag-free nanoparticle sorting platform that exploits electro-viscoelastic microfluidic (EVM) migration for the high-fidelity, continuous-flow isolation of virus-like particle (VLP) assemblies. This migration mechanism can overcome Brownian fluctuations, which are typically dominant on the nanoscale, confining the target assemblies to central streamlines for selective collection. In a single pass, the system segregates 40 nm VLPs from 6 nm excess antigen monomers, increasing the VLP purity by 20.2%. A sacrificial electrode outlet directs undesired electrohydrodynamic effects to the waste, preserving the VLP-rich product stream. Our results offer an alternative downstream framework for the rapid purification and quality control of complex bionanomaterials, establishing a scalable pathway for precision nanomedicine processing.