Engineering the Size of Bicontinuous Nanospheres via Multi-Inlet Vortex Mixing

Bicontinuous nanospheres (BCNs) are self-assembled nanostructures with interconnected aqueous channels that enable the coloading of hydrophilic and hydrophobic cargo; however, their size has been difficult to control. Here, we present a scalable approach to tune the size distribution of poly(ethylene glycol)-b-poly(propylene sulfide) BCNs using a multi-inlet vortex mixer. Higher mixing times and polymer concentrations produced larger BCNs, while shorter mixing times and lower concentrations yielded spherical micelles. Small-angle X-ray scattering and cryogenic transmission electron microscopy confirmed the BCN bicontinuous morphology, which persisted at smaller sizes. The porous BCN structure resulted in increased surface roughness compared to polymersomes (PSs). In vitro, BCNs and PSs of comparable sizes recruited distinct protein coronas early, but their profiles showed convergence by 24 h. In vivo, organ biodistribution was determined primarily by the nanocarrier size rather than the morphology. These findings establish a robust approach to BCN fabrication while revealing dynamic biological interactions that inform nanocarrier design.