This thesis focuses on the development of two new applications using ion concentration polarization (ICP): an out-of-plane microfluidic approach for water desalination and a method for concentration and transportation of charged analytes in paper-based biomedical diagnostic device. In the first work, we present an out-of-plane desalination approach using ICP. A depletion boundary separates salt ions and purified water into distinct vertically stacked layers. The out-of-plane design enables multiplexing in three dimensions, providing the functional density required for practical applications. The second work demonstrates an active control mechanism of target analytes in paper using ICP. Both external devices (with all functional units on one side of paper) and integrated paper microfluidic devices (by embedding all functional units in paper) were developed to concentrate and transport charged analyte molecules in the paper. We also demonstrate a new fabrication method of nanofluidic and hydrophobic barriers (nanoporous membrane patterning) in paper microfluidic device.

This thesis focuses on the development of two new applications using ion concentration polarization (ICP): an out-of-plane microfluidic approach for water desalination and a method for concentration and transportation of charged analytes in paper-based biomedical diagnostic device. In the first work, we present an out-of-plane desalination approach using ICP. A depletion boundary separates salt ions and purified water into distinct vertically stacked layers. The out-of-plane design enables multiplexing in three dimensions, providing the functional density required for practical applications. The second work demonstrates an active control mechanism of target analytes in paper using ICP. Both external devices (with all functional units on one side of paper) and integrated paper microfluidic devices (by embedding all functional units in paper) were developed to concentrate and transport charged analyte molecules in the paper. We also demonstrate a new fabrication method of nanofluidic and hydrophobic barriers (nanoporous membrane patterning) in paper microfluidic device.