Development of a low flow‐resistive charged nanoporous membrane in a microchip for fast electropreconcentration

Abstract

A nanoporous poly-(styrene sulfonate) (poly-SS) membrane was developed for fast and selective ion transport in a microfluidic chip. The poly-SS membrane can be photopolymerized in-situ at arbitrary location of a microchannel, enabling integrated fluidics design in the microfluidic chip. The membrane is characterized by a low hydraulic resistance and a high surface charge to maximize the electroosmotic flow and charge selectivity. The membrane characteristics were investigated by charge-selective electropreconcentration method. Experimental results show membranes with various percentages of poly-SS are able to concentrate anions (fluorescein and TRITC-labeled BSA). The anion-selective electropreconcentration process is stable and 26-times faster than previously reported poly-AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) based system. The electropreconcentration was also demonstrated to depend on the sample valency and buffer concentration.

Freeform Membranes with Tunable Permeability in Microfluidics

“…PDMS has excellent biocompatibility and low autofluorescence, making it a versatile material for different applications and characterization methods. [56] To connect hydrophilic membrane materials to the hydrophobic PDMS, treatments with silyl acrylates [2,9,10,[57][58][59] or radical initiators [60,61] can provide an anchor for the membrane to which it can be chemically bonded during fabrication. However, the main challenge with the functionalization of PDMS surfaces is their dynamic nature.…”

Microfluidics: Innovations in Materials and Their Fabrication and Functionalization

“…Although the chip material was compatible with cell growth, the fabrication process was not straightforward. Chun 131 demonstrated rapid and selective ion transport by implementing a 30 μm length, porous polystyrenesulfonate membrane in a microfluidic channel. The membrane was fabricated by photolithography and had low hydraulic and electrical resistance.…”

Recent advances in paper‐based preconcentrators by utilizing ion concentration polarization

“…Gallibu et al [76] used ink to form hydrophobic channels on chromatographic paper to produce a paper-based preconcentrator. In addition, several researchers have combined paper-based and ion-selective membranes [77,78] and applied voltage to produce an ICP preconcentration effect. The repeatability of ICP paper-based preconcentrator is generally poor.…”