Non-Negligible Diffusio-Osmosis Inside an Ion Concentration Polarization Layer

Micro and Nano Syst Lett

2017

Self Cite

Recently, novel biomolecules separation and detection methods based on ion concentration polarization (ICP) phenomena have been extensively researched due to its high amplification ratio and high-speed accumulation. Despite of these bright advances, the fabrication of conventional ICP devices still have complicated and times-consuming tasks. As an alternative platform, a paper have been recently used for the identical ICP operations. In this work, we demonstrated the selective preconcentration of a muc1 gene fragment as human breast cancer marker and a lamp-2 gene fragment as the cause of Danon disease in paper-based ICP devices. As a result, these two DNA fragments were successfully concentrated up to ~60 fold at different location in a single paper-channel. The device would be a promising platform for point-of-care device due to an economic fabrication, the easy extraction of concentrated sample and an easy disposability.

Section: Overlimiting Current In the Paper-based Icp Devicementioning

confidence: 79%

“…Recently, novel biomolecules separation and detection methods based on ion concentration polarization (ICP) phenomena have been extensively developed [2][3][4][5][6]. The ICP phenomena that is generated near the interface of a microfluidic channel and perm-selective nanojunction causes the depletion zone at the anodic side of the membrane.…”

Section: Introductionmentioning

confidence: 99%

Paper-based ion concentration polarization device for selective preconcentration of muc1 and lamp-2 genes

Son

Lee

Micro and Nano Syst Lett

2017

Self Cite

“…If one can extract the solution from the ion depletion zone, one can use it as portable scale electro-desalination / purification [1,[24][25][26][27] device. However, shared fundamental aspects of ICP and CP have been actively studied such as vortex generation [9][10][11]28], stabilization [17,[29][30][31], mechanism of overlimiting current [12][13][14]16,18,20], phenomenon near nanopores [32][33][34][35] and concentration profile including pH variation [36][37][38], etc.…”

Section: Introductionmentioning

confidence: 99%

Controllable pH Manipulations in Micro/Nanofluidic Device Using Nanoscale Electrokinetics

Park

2020

Micromachines

Recently introduced nanoscale electrokinetic phenomenon called ion concentration polarization (ICP) has been suffered from serious pH changes to the sample fluid. A number of studies have focused on the origin of pH changes and strategies for regulating it. Instead of avoiding pH changes, in this work, we tried to demonstrate new ways to utilize this inevitable pH change. First, one can obtain a well-defined pH gradient in proton-received microchannel by applying a fixed electric current through a proton exchange membrane. Furthermore, one can tune the pH gradient on demand by adjusting the proton mass transportation (i.e., adjusting electric current). Secondly, we demonstrated that the occurrence of ICP can be examined by sensing a surrounding pH of electrolyte solution. When pH > threshold pH, patterned pH-responsive hydrogel inside a straight microchannel acted as a nanojunction to block the microchannel, while it did as a microjunction when pH < threshold pH. In case of forming a nanojunction, electrical current significantly dropped compared to the case of a microjunction. The strategies that presented in this work would be a basis for useful engineering applications such as a localized pH stimulation to biomolecules using tunable pH gradient generation and portable pH sensor with pH-sensitive hydrogel.

“…Recent nanoscale electrokinetic researches have focused on understanding a novel ion transportation through nanoporous membrane 1, 2 or nanochannel system 3–7 , since it forms essential basis for developing various engineering applications such as nanofluidic diodes 8–12 , energy harvesting device 13, 14 , (bio-)molecular preconcentrator 15–20 and electro-desalinator 21–25 . Among the interesting transport phenomena, ion concentration polarization (ICP) has drawn significant attentions because it describes the motion of ions under an electric field, which resembles a phenomenon occurs inside a body or a cell 26, 27 .…”

Section: Introductionmentioning

confidence: 99%

“…The fingerprinting evidence of these zones has been reported as the appearance of the Ohmic-limiting-overlimiting current regimes 28 . Especially, the source of overlimiting current, which was unable to be described by a conventional diffusion-drift theory 26 , has been debated for a decade to include the dominance regime of extended space charge layer 31 , surface conduction 1, 5 , electro-diffusio-convection 2, 28, 32 and electroosmotic instability 33, 34 . Once the porous material has the permselectivity, the deterministic factors of distinguishing the regimes are external parameters such as the characteristic dimensions of bulk environment, the surface charges of building substrates and the bulk electrolyte concentrations 5 .…”

Section: Introductionmentioning

confidence: 99%

Ion Concentration Polarization by Bifurcated Current Path

Cho

Lee

et al. 2017

Sci Rep

Self Cite

Ion concentration polarization (ICP) is a fundamental electrokinetic process that occurs near a perm-selective membrane under dc bias. Overall process highly depends on the current transportation mechanisms such as electro-convection, surface conduction and diffusioosmosis and the fundamental characteristics can be significantly altered by external parameters, once the permselectivity was fixed. In this work, a new ICP device with a bifurcated current path as for the enhancement of the surface conduction was fabricated using a polymeric nanoporous material. It was protruded to the middle of a microchannel, while the material was exactly aligned at the interface between two microchannels in a conventional ICP device. Rigorous experiments revealed out that the propagation of ICP layer was initiated from the different locations of the protruded membrane according to the dominant current path which was determined by a bulk electrolyte concentration. Since the enhancement of surface conduction maintained the stability of ICP process, a strong electrokinetic flow associated with the amplified electric field inside ICP layer was significantly suppressed over the protruded membrane even at condensed limit. As a practical example of utilizing the protruded device, we successfully demonstrated a non-destructive micro/nanofluidic preconcentrator of fragile cellular species (i.e. red blood cells).