Electrokinetic Microfluidics at the Convergence Frontier: From Charge-Driven Transport to Intelligent Chemical Systems

TL;DR

This paper explores how electrokinetic microfluidics is advancing to create smart chemical systems for better analytical chemistry and diagnostics.

Contribution

The paper identifies five emerging research directions in electrokinetic microfluidics, emphasizing integration and complexity.

Findings

Asymmetric interfacial structures like Janus droplets enable unconventional transport modes.

Electrokinetic injection techniques are crucial for high-resolution separations and analytical accuracy.

Electrokinetic enrichment strategies can selectively accumulate trace analytes for improved detection.

Abstract

Electrokinetics has established itself as a central pillar in microfluidic research, offering a powerful, non-mechanical means to manipulate fluids and analytes. Mechanisms such as electroosmotic flow (EOF), electrophoresis (EP), and dielectrophoresis (DEP) re-main central to the field, once more layers of complexity emerge heterogeneous interfaces, viscoelastic liquids, or anisotropic droplets are introduced. Five research directions have become prominent. Field-driven manipulation of droplets and emulsions—most strikingly Janus droplets—demonstrates how asymmetric interfacial structures generate unconventional transport modes. Electrokinetic injection techniques follow as a second focus, because sharply defined sample plugs are essential for high-resolution separations and for maintaining analytical accuracy. Control of EOF is then framed as an integrated design challenge that involves tuning surface chemistry, engineering zeta potential, implementing nanoscale patterning, and navigating non-Newtonian flow behavior. Next, electrokinetic instabilities and electrically driven micromixing are examined through the lens of vortex-mediated perturbations that break diffusion limits in low-Reynolds-number flows. Finally, electrokinetic enrichment strategies—ranging from ion concentration polarization focusing to stacking-based preconcentration—demonstrate how trace analytes can be selectively accumulated to achieve detection sensitivity. Ultimately, electrokinetics is converging towards sophisticated integrated platforms and hybrid powering schemes, promising to expand microfluidic capabilities into previously inaccessible domains for analytical chemistry and diagnostics.

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