• Rapid paper-fluidic analytical device fabrication by cut-and-insert method
    Graphical abstract: Rapid fabrication of versatile omni-directional and long-distance three-dimensional flow paper-fluidic analytical devices using a cut-and-insert method for biomedical applicationsPaper fluidics has recently offered an approach to precisely guide liquid flow in analytical devices with a low-cost regime. Multiple paper layers expand the capability of analytical devices to handle multiple samples as well as multiple detections simultaneously. Here we present a novel inexpensive cut-and-insert method to achieve a well-controlled even distribution of liquid in multi-channel three-dimensional (3D) paper-based analytical devices. A novel vacuum-driven poly dimethyl siloxane (PDMS) stamping method to pattern hydrophobic barriers in the filter paper enables rapid fabrication and assembly of microfluidic paper-based analytical devices (μ-PADs). The cut-and-insert assembly method facilitates more efficient fluid transfer than conventional O2plasma-assisted overlapped channel binding, due to the strong physical contact between connected layers. The liquid transfer starts from the center region where two inserted layers are overlapped, and thus the presented method enables consistent liquid transfer independent of the angles of connected fluidic paths. Consequently, the angles between the connected μ-PAD strips as well as the 3D distance for the fluid transfer can be freely adjusted as needed. Also, multiple strips can be easily connected in series or in parallel. For example, perpendicularly connected bended paper channels guide upward and then lateral liquid flows by capillary action. Three important assays, i.e. nitrite 0 to 2 ppm, pH 1 to 10, and glucose 0 to 0.22 molL−1, were successfully implemented and measured simultaneously using a device with four strips connected in parallel.

    Analytical Methods, 10, 4648, 2018. 

    DOI: 10.1039/c8ay01318g 

    Posted Feb 15, 2019, 12:38 PM by W G
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Bionanotechnology, Biomedical Engineering, Biochemical Engineering, BioMEMS,  Biosensor, Bioseparations

  • BioMEMS and Biosensor development
  • Separation and identification of biomolecules including protein and human cancer and stem cells
  • Rapid on-site environmental monitoring
  • Wearable diagnostic health monitoring 


  • Chang-Koo Yun, Jung Wook Hwang, Tae Joon Kwak, Woo-Jin Chang, Kyubeom Han, Sanhyun Lee, Yong-Soo Choi, Nanoinjection system for precision direct delivery of large molecules, Lab Chip, 19, 580-588, 2019. (cover article) Link 
  • Naseem Abbas, Xun Lu, Mohsin Ali Badshah, Jung Bin In, Won Il Heo, Kui Young Park, Mi-Kyung Lee, Cho Hee Kim, Pilwon Kang, Woo-Jin Chang, Seok-min Kim and Seong Jun Seo, Development of a Protein Microarray Chip with Enhanced Fluorescence for Identification of Semen and Vaginal Fluid, Sensors, 18, 3874, 2018. Link

Recent News

  • Two interns join the group through Korea WEST program Jinbok Lee and Mirim Kim joined group through Korea WEST program from March 2020. Welcome!!
    Posted Apr 8, 2020, 8:15 PM by W G
  • Rizwen received Chancellor's Award Rizwen received Chancellor's Award in Spring 2020. Congratulations!!
    Posted Apr 8, 2020, 8:14 PM by W G
  • Philip Yoo joined the group for Summer Philip is supported by UWM undergraduate research for incoming students program in summer. Congratulations and welcome Philip
    Posted Jul 14, 2019, 7:34 AM by W G
  • Tae Joon passed defense Tae Joon passed defense. Congratulations Dr. Kwak!!!
    Posted May 21, 2019, 9:31 PM by W G
  • Tae Joon received CEAS Academic Excellence Award Tae Joon received CEAS Academic Excellence Award.  This award honors students who have achieved exceptional academics, demonstrated outstanding research, provided service to UWM and the Milwaukee community and showed strong ...
    Posted May 6, 2019, 8:54 AM by W G
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