title: Sorting directionally oriented microstructures using railed microfluidics.
abstract: We demonstrate the microfluidic sorting of directionally oriented (anisotropic) microstructures by their orientational state in solution using the concept of railed microfluidics. After being injected into a microfluidic channel, the microstructures rotate and flip in various directions. In order to sort microstructures in an organized way, we designed the microstructures and the microchannel to allow for orientation-based control of microstructure movement. In order to sort microstructures based on their rotation, we used a wedge shaped fin on the microstructures and a Y-shaped railed microfluidic channel. For sorting flipped particles, we use a double-railed microfluidic channel that has grooves on both its top and bottom surfaces. By integrating the two sorting methods we demonstrated high throughput, autonomous sorting into four different orientational states: unrotated-unflipped, rotated-unflipped, unrotated-flipped, and rotated-flipped. Here we not only demonstrate orientational assembly of directionally dependent microstructures, but also present design considerations for future work.
authors.affiliation: School of Electrical Engineering and Computer Science, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul, 151-744, Korea.
authors.forename: Wook
authors.initials: W
authors.lastname: Park
authors.forename: Hosuk
authors.initials: H
authors.lastname: Lee
authors.forename: Hyungsung
authors.initials: H
authors.lastname: Park
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Kwon