Control of cell migration direction by inducing cell shape asymmetry with patterned topography

Abstract

In this study, we explored the concept of introducing asymmetry to cell shapes by patterned cell culture substrates, and investigated the consequence of this induced asymmetry to cell migration behaviors. Three patterns, named "Squares", "Grating", and "Arcs" were fabricated, representing different levels of rotational asymmetry. Using time-lapse imaging, we systematically compared the motility and directionality of mouse osteoblastic cells MC3T3-E1 cultured on these patterns. Cells were found to move progressively faster on "Arcs" than on "Grating", and cells on "Squares" were the slowest, suggesting that cell motility correlates with the level of rotational asymmetry of the repeating units of the pattern. Among these three patterns, on the "Arcs" pattern, the least symmetrical one, cells not only moved with the highest velocity but also the strongest directional persistence. Although this enhanced motility was not associated with the detected number of focal adhesion sites in the cells, the pattern asymmetry was reflected in the asymmetrical cell spreading. Cells on the "Arcs" pattern consistently displayed larger cytoplasmic protrusion on one side of the cell. This asymmetry in cell shape determined the direction and speed of cell migration. These observations suggest that topographical patterns that enhance the imbalance between the leading and trailing fronts of adherent cells will increase cell speed and control movement directions. Our discovery shows that complex cell behaviors such as the direction of cell movement are influenced by simple geometrical principles, which can be utilized as the design foundation for platforms that guide and sort cultured cells.

Correlation of focal adhesion assembly and disassembly with cell migration on nanotopography

“…These results should be contrasted with findings in other studies that show cells on nanolines (width = 350 nm to 6 μm, spacing = 70 nm to 4 μm) where it is reported that they travel farther than those on flat surfaces. 30–32 However, our results are similar to those of Ferrari et al ., in which cells on nanolines of similar size as L860 traveled a shorter distance over time compared to cells on flat surfaces. 17 This suggests that the size of the line gratings may affect the formation of the adhesions and, as suggested by Ferrari et al, cytoskeletal structures that are needed in the correct orientation optimal for migration.…”

A Unidirectional Cell Switching Gate by Engineering Grating Length and Bending Angle

“…In consistent with previous observations, MC3T3-E1 cells generally migrated along the grating in the patterns, whereas cells on a flat PDMS surface moved in random-walk manner [ 52 ]. In the first series of experiments, we asked how the sharpness of the bend influenced the migration of MC3T3-E1 cells.…”

“…More reversals appear to occur at discontinuities of the pattern, such as bends and ends, possibly due to the localized and temporary asymmetry between the cell leading and trailing edges induced by the abrupt changes of the microenvironment. Surfaces that harbour topographical patterns [ 52 ] or microimprinted adhesion molecules [ 53 , 54 ] designed to introduce asymmetry to cell shape are known to influence cell speed and directionality.…”

Cellular and Subcellular Contact Guidance on Microfabricated Substrates

“…Nanopillared surfaces also induce more random orientation and morphology compared to nanogrooves (Choi et al, 2007;Lamers et al, 2010;Ning et al, 2016). For both ranges of pillar dimensions, migrating cells show less directional movement compared to flat or grooved substrates (Frey et al, 2006;Lamers et al, 2010;Tang et al, 2014;Liang et al, 2017). The influence of multidirectional cues on cell motility is however less clear.…”

“…A first class of multidirectional topographies used in the literature includes arrays of pillars of different shapes (i.e., round, square, or hexagonal: see, e.g., Micholt et al, 2013;Tang et al, 2014;Liang et al, 2017), dimensions and rotational or line symmetry ( Figures 1E,F). Cell responses to multidirectional cues are usually quite different from those on unidirectional topographies ( Table 2).…”