Engineered nanofluidic preconcentration devices by ion concentration polarization

A nanofluidic preconcentration device utilizing an ion concentration polarization (ICP) phenomenon has been regarded as one of the most efficient mechanism for preconcentrating low abundant molecules to be detected. In this review, a short fundamental aspect behind ICP was introduced and detailed engineering endeavors to enhance the performance of the preconcentration device were followed. While a conventional nanostructure based on silicon or glass substrate lose its ion-selectivity at a physiologically relevant electrolyte concentration, Nafion as a highly charged nanoporous material would maintain its permselectivity at the concentration so that various fabrication processes utilizing Nafion were introduced. In order to extend the capability of the device in terms of preconcentration factor and throughput, dual gates, “U”-shaped and one-channel device were shown with their pros and cons. Last section would introduce the most recent development of preconcentration mechanism; the simultaneous preconcentration with separation, the radial preconcentration and the two stress-free preconcentration mechanisms. Conclusively, this review would not only provide the key insight of development history of the nanofluidic preconcentration device but also contribute for creating the next generation preconcentration mechanisms.