Preconcentration of Fluorescent Dyes in Electromembrane Systems via Electrophoretic Migration

Abstract

Microfluidic preconcentration enables the collection or extraction of low-abundance analytes at specific locations. It has attracted considerable attention as an essential technology in bioengineering, particularly for detection and diagnosis. Herein, we investigated the key parameters in the preconcentration of fluorescent dyes based on electrophoresis in a microfluidic electromembrane system. Commercial ion-exchange membrane (IEM)-integrated polydimethylsiloxane microfluidic devices were fabricated, and Alexa Fluor 488 and Rhodamine 6G were used as fluorescent dyes for sample preconcentration. Through experimental studies, the effect of the channel concentration ratio (CCR, concentration ratio of the main and buffer channels) on the performance of the sample preconcentration was studied. The results show that the preconcentration of the target sample occurs more effectively for a high CCR or high salt concentration of the main channel when the CCR is constant. We also demonstrate a phenomenon that the salt concentration in the electrolyte solution increases as the preconcentration progresses. Our results provide consolidated conditions for electrophoresis-based sample preconcentration in electromembrane systems.

Enhanced Salt Removal of Fresh Water by Recovery-Reduced Ion Concentration Polarization Desalination

“…Moreover, even though the applied voltage increases (i.e., the overlimiting regime), electroconvection on the AEM could weaken, which arises from proton generation on the AEM surface. In ICP desalination, although ions looked concentrated by electric field-induced migration, a high salt removal rate was observed when the thickness of the electroconvection was similar to the outlet width, as confirmed by the 10 mM NaCl feed ( Figure 4 b,c) [ 32 , 33 , 38 ]. After all, ICP desalination exhibits a high SRR of more than 90%, while electrodialysis shows an SRR of less than 50% in low-concentration (0.1 mM NaCl) desalination.…”