title: Capillarity ion concentration polarization for spontaneous biomolecular preconcentration mechanism.
abstract: Ionic hydrogel-based ion concentration polarization devices have been demonstrated as platforms to study nanoscale ion transport and to develop engineering applications, such as protein preconcentration and ionic diodes/transistors. Using a microfluidic system composed of a perm-selective hydrogel, we demonstrated a micro/nanofluidic device for the preconcentration of biological samples using a new class of ion concentration polarization mechanism called "capillarity ion concentration polarization" (CICP). Instead of an external electrical voltage source, the capillary force of the perm-selective hydrogel spontaneously generated an ion depletion zone in a microfluidic channel by selectively absorbing counter-ions in a sample solution. We demonstrated a reasonable preconcentration factor (∼100-fold/min) using the CICP device. Although the efficiency was lower than that of conventional electrokinetic ICP operation due to the absence of a drift ion migration, this mechanism was free from the undesirable instability caused by a local amplified electric field inside the ion depletion zone so that the mechanism should be suitable especially for an application where the contents were electrically sensitive. Therefore, this simple system would provide a point-of-care diagnostic device for which the sample volume is limited and a simplified sample handling is demanded.
authors: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology , 335 Gwahangno, Yuseong-gu, Daejeon 305-701, South Korea.
authors: Yoonjee
authors: Y
authors: Oh
authors: Hyomin
authors: H
authors: Lee
authors: Department of Electrical and Computer Engineering, Seoul National University , 1 Gwanakro, Gwanakgu, Seoul 151-744, South Korea.
authors: Seok Young
authors: 0000-0001-6747-337X
authors: SY
authors: Son
authors: Sung Jae
authors: SJ
authors: Kim
authors: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology , 335 Gwahangno, Yuseong-gu, Daejeon 305-701, South Korea.
authors: Pilnam
authors: 0000-0002-5592-4599
authors: P
authors: Kim