(a) Schematic diagram of the microchannels with slanted groove arrays for particle hydrophoresis sorting and focusing. Reproduced with permission from Song et al., J. Chromatogr., A 1302, 191 (2013). Copyright 2013 Elsevier. (b) Schematic diagram of a microchannel with a series of inclined and gradually changing grooves for size-based cell sorting. Reproduced with permission from Song et al., Lab Chip 15, 5 (2015). Copyright 2015 Royal Society of Chemistry. (c) Schematic diagram of a microchannel for separating magnetic and non-magnetic particles through magnetic force and hydrophoresis. Reproduced with permission from Yan et al., Appl. Phys. Lett. 109, 21 (2016). Copyright 2016 AIP Publishing LLC. (d) Schematic diagram of the distribution of Jurkat cells and RBCs at the cross section of the channel after flowing through the microchannel with arc-shaped groove structure. Reproduced with permission from Yan et al., Micromachines 8, 11 (2017). Copyright 2017 Molecular Diversity Preservation International. (e) Schematic diagram of the microchannel for manipulating and focusing small particles with the assistance of sheath flow. Reproduced with permission from Zhao et al., Microfluid. Nanofluid. 23, 1 (2019). Copyright 2019 Springer Publishing. (f) Schematic diagram of the double-layer microchannel consisting of a straight channel with contraction–expansion arrays and slanted grooves. Reproduced with permission from Yan et al., Biomed. Microdevices 20, 2 (2018). Copyright 2018 Springer Publishing.