Electrokinetic active grooves for liposome capture, confinement, trajectory analysis and controlled release

Abstract

Extracellular vesicles (EVs) are attractive candidates for minimally invasive disease monitoring. EV diagnostic signals often reside in low-abundant subpopulations, motivating single-vesicle measurements that can report distributions rather than ensemble averages. In practice, such assays rely on transient migration of a mobile vesicle through a detection region or performing cycled processing/measurement steps on vesicles permanently immobilized on surfaces via affinity-based capture. Single vesicle analysis would benefit from technologies that can combine characteristics of transient detection and surface immobilization to enable controlled capture, fixed time analysis and release of vesicles in a marker-neutral way. Here, we present electrokinetically active (RECON) grooves that provides low-voltage, programmable capture, timed retention, and release of nanoscale vesicles within microscopic grooves under continuous optical access. The platform uses a titanium embedded electrode with thin TiO2 passivation, enabling stable actuation over multi-hour experiments. Using fluorescent, size-defined liposomes as standards, we demonstrate (1) reversible, minute-long confinement at <5 V, (2) size-dependent confinement times, and (3) optical quantification of groove-guided drift velocities. Together, these results establish RECON grooves as a reusable, electrically programmable platform for controlled capture, timed retention, and release, while providing quantitative, trajectory-derived measures of confinement and transport.