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Nanostructured Biointerfaces
Published in Šeila Selimovic, Nanopatterning and Nanoscale Devices for Biological Applications, 2017
Jean Paul Allain, Monica Echeverry-Rendón, Juan Jose Pavón, Sandra L. Arias
Thus, mechanical forces applied to a cell may be linked to the apparatus for gene expression. The reaction of cells to the mechanical properties of the substratum has been described and named durotaxis [24]. In particular, it refers to the cell migration directed by a gradient in the stiffness along a particular surface (e.g., gradient in surface morphology). Presumably, the cells can detect these properties by applying mechanical forces to the underlying layers and measuring their movement. That is why the elasticity of a nanostructured biointerface becomes so important. Thus, cells are sensing and reacting to an appreciable thickness of the substratum. In this way, cells may be able to detect “buried” features. Thus, the elasticity of a nano-structured surface should affect the mechanical properties of any overlying layers to some extent by altering the compliance of the substratum, and the cell will detect this as the strains coming back to its sensing systems. Since nanoimprinting of the cell can occur, this is likely to be a mechanical process and can add itself onto any chemical interactions.
Tuning Cellular Behaviors during Self-Organization of Cells in Hydrogel by Changing Inner Nano-Structure of Hydrogel
Published in Xiaolu Zhu, Zheng Wang, Self-Organized 3D Tissue Patterns, 2022
Further, recent work has also studied the impact of heterogeneity in hydrogel stiffness on cellular spreading, migration, or differentiation. For example, the cells in heterogeneously stiff substrates have been observed to elongate or migrate more toward the stiffer part of the substrate, which can be termed as durotaxis [67–69]. Durotaxis is one of the effective factors to guide cell directional motility [70]. For instance, the migratory response of 3T3 fibroblast cells was found consistent with the durotaxis prediction on the micro-patterned hydrogel [71] and previous work has proved the effect of durotaxis on the hydrogel with cell-scaled heterogeneous elasticity [72]. However, the built heterogeneous stiffness of matrix usually had remarkably larger dimensions than or close to that of individual cells (10 μm or larger) [73, 74]. In order to further explore the effect of nano- or molecular-scaled heterogeneous stiffness of hydrogel matrix on individual cellular behaviors, including morphology and phenotype, we also demonstrated another rational and easy-to-implement strategy [75] that can tune the stiffness fluctuation within a local area just covered by an individual cell. This method is different from the scheme that is stated and discussed in Section 6.4.3. RGD-clustering induced stiffness-heterogeneity usually involves smaller variation of stiffness because it is induced by the smaller variation of RGD concentration under the condition that the total common sites for binding RGD peptides and crosslinkers are kept as constant; while the method in literature [75] can offer a larger variation of stiffness within a single cell region by directly manipulating the amount proportion of crosslinkers in the two parts with equal quantity — lowly crosslinking part (L-part) and highly crosslinking part (H-part).
Design Considerations for 3D Cardiovascular Tissue Scaffolds
Published in Karen J.L. Burg, Didier Dréau, Timothy Burg, Engineering 3D Tissue Test Systems, 2017
Scott Cooper, Christopher Moraes, Richard L. Leask
It has been demonstrated that cells sense their environment and can therefore control motility and morphology based on substrate stiffness, a process termed “durotaxis.” Researchers studying mouse fibroblasts observed that they preferentially moved in the direction of stiffer polyacrylamide gel gradients and that these cells could produce more traction on stiffer substrates (Lo et al. 2000).
On the importance of substrate deformations for cell migration
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
A. Gagnieu, G. Chagnon, Y. Chemisky, A. Stephanou, A. Chauvière
Cell migration is essential for many biological processes such as tissue morphogenesis, wound healing or metastatic invasion in cancer. It is a complex and highly regulated phenomenon closely guided and fine-tuned by both chemical and mechanical cues. Whereas chemoattraction has been extensively studied, the mechanical influence remains to be fully elucidated. Although cell sensitivity to the substrate rigidity is known under the term durotaxis (Marzban et al. 2018) and substrate anisotropy is known to influence cellular organization (Checa et al. 2015) much less is known about cell sensitivity to environmental stresses and strains. This paper proposes to specifically focus on the cell sensitivity to substrate deformations during migration. Those are assumed to play a role in long-range cell-cell interactions (Han et al. 2018) by which a cell deforms the substrate (Tanimoto and Sano 2014) and influences the orientation of migration of other cells in its neighbourhood. This form of mechanotaxis (to which we will refer as strain mechanosensing) could in particular explain how cells migrate towards each other to form vascular loops during angiogenesis when chemotaxis is ruled out.
A review on control of droplet motion based on wettability modulation: principles, design strategies, recent progress, and applications
Published in Science and Technology of Advanced Materials, 2022
Mizuki Tenjimbayashi, Kengo Manabe
Examples of droplet transportation based on Strategy II are shown in Figure 8(a). This type of droplet transportation is often found in nature. The material and process approach to forming gradient structures using technology has been reported. Figure 8(b–h) show the spontaneous transport of water droplets in nature using a curvature gradient structure. As shown in Figure 8(b), a waterfowl needs to transport water droplets from the tip of its beak to its root to drink water; a gradient structure of curvature is used for this purpose [127]. As shown in Figure 8(c), cactus spines and trichrome of nepenthes pitcher plant have a gradient curvature structure for the collection of water toward the cactus root [128,129]. The hair-like projections of the cactus use a similar mechanism to achieve the spontaneous transport of water droplets [128]. Figure 8(d) shows the phenomenon of water droplet collection in a spider web [130]. Spider webs have a micrometer-sized spinning structure, and water droplets are collected in the spinning structure. Figure 8(e) presents the water-harvesting mechanism of the Namib beetle [131]. The Namib beetle has a hump-shaped hierarchical projection on its back, and this structure enables water collection. In Figure 8(f), the legs of the water strider have curvature gradients to repel water [132–134]. Micro-scale curvature gradients are used to prevent the water from penetrating between the legs. In Figure 8(g), nanometer-scale curvature gradient structures are observed on the surface of cicada wings [135]. Experimental studies have reported that this structure effectively promotes microdroplet fusion and ultimately removes water from the wings [136]. Figure 8(h) shows Durotaxis, a form of cell migration [137–139]. Cells move by forming a stiffness gradient during their migration. Recently, studies that consider cells as droplets have been reported, and this is also included as an example of spontaneous transport by a gradient [140].