Graphene Oxide-Functionalized Thread-Based Electrofluidic Approach for DNA Hybridization

A novel, low-cost, and disposable thread-based electrofluidic analytical method employing isotachophoresis (ITP) was developed for demonstrating surface DNA hybridization. This approach was based on graphene oxide (GO) surface-functionalized zones on nylon threads as a binding platform to trap a fluorescently labeled isotachophoretically focused single-stranded DNA (ssDNA) band, resulting in quenching of the fluorescence, which signaled quantitative trapping. In the event of an isotachophoretically focused complementary DNA (cDNA) band passing over the GO-trapped ssDNA zone, surface hybridization of the ssDNA and cDNA to form double-stranded DNA (dsDNA) band occurred, which is released from the GO-coated zones, resulting in restoration of the fluorescent signal as it exits the GO band and migrates further along the thread. This controllable process demonstrates the potential of the GO-functionalized thread-based microfluidic analytical approach for DNA hybridization and its visualization, which could be adapted into point-of-care (POC) diagnostic devices for real-world applications.