Figure 8.

Mechanical stimulation on endothelial cell behaviors by hydrogel‐based platforms. A) 3D bar graph of mechanical stimulation on endothelial cells for various cell activities and biomedical applications. The research conditions are evaluated based on h‐index of each field calculated by paper publication and citation data from Scopus. B) Schematic illustration of photopatterned hydrogel with stiffness heterogeneity, soft (black) and stiff (red) regions. Confocal images of 100‐µm‐pattern hydrogel indicate that endothelial cells preferentially grow on stiff ones during monolayer formation, compared to soft matrix regions. Reproduced with permission.^{[ 306 ]} Copyright 2017, American Chemical Society. C) Composite fluorescence images that endothelial cells have enhanced angiogenesis sprout length on low‐stiffness hydrogel. Dashed yellow lines indicate cell channel position. Reproduced with permission.^{[ 310 ]} Copyright 2017, Springer Nature. D) Images show that stiff hydrogel matrix supports and promotes arterial‐venous differentiation of endothelial progenitor cells. Reproduced with permission.^{[ 311 ]} Copyright 2018, Wiley‐VCH. E) Schematic illustration of the dip‐casting approach to form luminal microsize patterns on tubular hydrogel. Reproduced with permission.^{[ 313 ]} Copyright 2016, Elsevier. F) Schematic illustration of gel/microfluidic device to learn bifurcating shear flow at the vessel branch point. Reproduced with permission.^{[ 324 ]} Copyright 2019, MDPI. G) Immunocytochemistry images elucidate that shear stress promotes cell transformation from endothelial to mesenchymal cell, with increased alpha‐smooth muscle actin (α‐SMA). Reproduced with permission.^{[ 325 ]} Copyright 2016, Royal Society of Chemistry. H) Schematic illustration of gel stretcher and images of scanning electron microscope that endothelial cells orient perpendicularly to the stretch direction. Reproduced with permission.^{[ 339 ]} Copyright 2008, Elsevier.