title: A Unidirectional Cell Switching Gate by Engineering Grating Length and Bending Angle.
abstract: On a microgrooved substrate, cells migrate along the pattern, and at random positions, reverse their directions. Here, we demonstrate that these reversals can be controlled by introducing discontinuities to the pattern. On "V-shaped grating patterns", mouse osteogenic progenitor MC3T3-E1 cells reversed predominately at the bends and the ends. The patterns were engineered in a way that the combined effects of angle- and length-dependence could be examined in addition to their individual effects. Results show that when the bend was placed closer to one end, migration behaviour of cells depends on their direction of approach. At an obtuse bend (135°), more cells reversed when approaching from the long segment than from the short segment. But at an acute bend (45°), this relationship was reversed. Based on this anisotropic behaviour, the designed patterns effectively allowed cells to move in one direction but blocked migrations in the opposing direction. This study demonstrates that by the strategic placement of bends and ends on grating patterns, we can engineer effective unidirectional switching gates that can control the movement of adherent cells. The knowledge developed in this study could be utilised in future cell sorting or filtering platforms without the need for chemotaxis or microfluidic control.
authors.affiliation: Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong.|Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Shu Fan
authors.initials: SF
authors.lastname: Zhou
authors.affiliation: Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.|Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Singaram
authors.initials: S
authors.lastname: Gopalakrishnan
authors.affiliation: Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong.|Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Yuan Hao
authors.initials: YH
authors.lastname: Xu
authors.affiliation: Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.|Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.|Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Yun Wah
authors.initials: YW
authors.lastname: Lam
authors.affiliation: Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong.|Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Stella W
authors.initials: SW
authors.lastname: Pang
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018929:Cell Culture Techniques; D002465:Cell Movement; D048430:Cell Shape; D003470:Culture Media; D022001:Focal Adhesions / Q000378:metabolism; D051379:Mice
chemical_list: D003470:Culture Media
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