Hydrodynamic-Induced Conformational Transitions of Charged Macromolecules Dictate Anomalous Electroosmotic Flow

The transport of charged macromolecules through nanoconfined spaces is a fundamental phenomenon governing diverse cross-disciplinary systems, from biological viral packaging and cellular transport to artificial neuromorphic membranes and electrokinetic energy converters. Classically, translocating macromolecules are assumed to act as static steric barriers that passively impede local fluid transport, predictably suppressing electroosmotic flow (EOF). In this work, by coupling dissipative particle dynamics with continuum numerical modeling, we reveal a fundamentally distinct electro-hydrodynamic regime that breaks this universally applied steric exclusion paradigm. The results show that under extreme spatial confinement, negatively charged macromolecules trigger an anomalous, non-monotonic EOF enhancement. According to traditional understanding, significant steric blockage should severely diminish flow. However, we find that substantial macromolecular occlusion actually generates an emergent ''M-shaped'' velocity profile with remarkably high EOF velocities. This counterintuitive transport is driven by a dynamic, flow-induced conformational transition: intense localized shear gradients from the M-shaped profile force the extended macromolecule to collapse into a highly folded state, effectively circumventing the anticipated hydrodynamic resistance. Positively charged macromolecules undergo wall-adhering migration that strictly dampens the flow. Our unified mechanistic framework linking dynamic macromolecular conformation to non-linear fluidic modulation provides broad physical insights, establishing robust design principles for active soft-matter systems, stimuli-responsive smart nanofluidics, and high-precision electrokinetic sensors.