Digital microfluidics-like manipulation of electrokinetically preconcentrated bioparticle plugs in continuous-flow

Abstract

Herein, we demonstrate digital microfluidics-like manipulations of preconcentrated biomolecule plugs within a continuous flow that is different from the commonly known digital microfluidics involving discrete (i.e. droplets) media. This is...

Microvalve-Based Tunability of Electrically Driven Ion Transport through a Microfluidic System with an Ion-Exchange Membrane

“…The above described local microvalve-based controllability of the ICP and its associated preconcentration plug was not always achieved as it necessitates certain conditions as detailed herein. Previous studies [e.g., Park et al and Kim et al …”

“…The microvalves within the array can be operated simultaneously or in a certain sequence, dictated by the desired application. Such microvalve-based programmability replaces the need to pattern the CEM coating, e.g., into an array of individually addressable CEM pairs . For example, the dynamic operation sequence of two microvalves enabled control over the number of plugs formed and later merging them to a single plug, as shown in Figure A.…”

“…The above described local microvalve-based controllability of the ICP and its associated preconcentration plug was not always achieved as it necessitates certain conditions as detailed herein. Previous studies [e.g., Park et al 24 and Kim et al 25 ] using a fixed microchannel configuration resulted in ICP and plug generation only after a sufficiently large electric potential difference was applied. Thereby, to enable dynamic controllability over the ICP and its plug without changing the constantly applied electric potential difference, I Tot must kept below I Tot Lim for an opened microchannel.…”

“…The ionic depletion layer can be utilized also for separation of particles and enrichment based on coupling alternating current-driven dielectrophoresis with ICP effects . ICP-driven preconcentration is commonly realized within microfluidic channels with relatively high hydraulic permeability, either by employing the ionic permselective medium as a bridge between two microchannels ,− or as a patterned thin surface coating embedded at the bottom of the main microchannel. ,− The latter can be also realized using an electrode instead of an ionic permselective medium wherein the local ion concentration is modulated via electrochemical reaction (often termed faradic ICP). , These microfluidic system designs maintain minimal hydrodynamic interference within the microfluidic channels and support a sufficiently high flow rate and flux of target bioparticles toward the plug. However, for robust preconcentration, aside from the requirement for high throughput to achieve rapid bioparticle accumulation, precise overlap of the plug with the sensing region (e.g., immobilized molecular probes as antibodies , or electrodes for electrochemical sensing) is essential.…”

A Perturbed Asymmetrical Y-TypeSheathless Chip for Particle Control Based on Adjustable Tilted-Angle Traveling Surface Acoustic Waves (ataTSAWs)

“…However, a high flow rate may reduce cell activity and even cause cell death. The latter includes electrophoresis [ 16 , 17 ], magnetic separation [ 18 , 19 ], acoustic separation [ 20 , 21 ], and thermal and pneumatic controls [ 22 , 23 ]. Among them, the acoustic control technology has become an ideal choice for manufacturing bioseparation chips due to its advantages of good biocompatibility, low power consumption, simple manufacture, and easy control.…”