Patterned hydrogel islands were analyzed to engineer substrate elasticity.

<p>(A) Conceptual illustration of horizontal cell traction force of 20 nN on hydrogel island and analysis of deflection of individual island. (B) Hydrogel island deflection is plotted as a function of island modulus with differing background elasticities plotted. (C) Cell area of 12 µm spacing cases plotted versus correlating model peak deflections to show correlation between modeling and experimental components.</p

Hydrogel island elasticity regulates cell adhesion and spreading size in MSCs.

<p>(A) MSC adhered to pattern with 7 kPa islands, 12 kPa background elasticity, 3 µm spacing, and 100 µg ml⁻¹ FN with a cell area of 2,669 µm². Shown as brightfield image (top left), vinculin staining (top right), F-actin staining (bottom left), and merged image (bottom right). Average cell area for data point was 1174.54 µm²±113.16 µm². (B) MSC adhered to pattern with 105 kPa islands, 12 kPa background elasticity, 3 µm spacing, and 100 µg ml⁻¹ FN with a cell area of 6,134 µm². Shown as brightfield image (top left), vinculin staining (top right), F-actin staining (bottom left), and merged image (bottom right). Nucleus is shown in blue in all images. Average cell area for these conditions was 5847.13 µm²±260.56 µm². All scale bars are 50 µm.</p

DPN enables micropatterning of sub-cellular hydrogel substrates.

<p>(A) PDMS was spincoated onto glass slides to form a background of varying elasticity while utilizing DPN to deposit micropatterned hydrogel islands also with varying elasticity. These sub-cellular islands were functionalized with fibronectin at differing ligand densities, which facilitated cell attachment to substrate. (B) Micropatterned PEG hydrogel islands spaced at 12 µm distance between islands showing 100 µg ml⁻¹ BSA-FITC conjugated protein covalently bonded.</p

ROCK inhibited cells lose ability to sense matrix conditions.

<p>Cells were treated for 7 days, which prevented cells from sensing matrix conditions and spreading as was previously found. (A) ROCK inhibited cell on pattern of 7 kPa PEG, 2.5 MPa background elasticity, 7 µm spacing, and 50 µg ml⁻¹ ligand density with brightfield image and vinculin, F-actin, and nucleus staining merged image. Average cell area for this ROCK inhibited trial was 1184.37 µm²±223.84 µm². (B) ROCK inhibited cell on pattern of 105 kPa PEG, 2.5 MPa background elasticity, 7 µm spacing, and 50 µg ml⁻¹ ligand density with brightfield image and vinculin, F-actin, and nucleus staining merged image. Average cell area for this ROCK inhibited trial was 1175.46 µm²±265.79 µm². Error bars are standard error of over 10 cells quantified per condition.</p

Mechanical property values for the baseline AAA (underlined) and associated parametric studies.

<p>Mechanical property values for the baseline AAA (underlined) and associated parametric studies.</p

Mechanical properties for referent normal aortic tissue.

<p>Mechanical properties for referent normal aortic tissue.</p

Referent normal aortic and baseline AAA geometries.

<p>(A) Referent normal aortic geometry in XZ- and YZ-planes; L is the length of abdominal aorta, D is the outer diameter, t is the thickness, R_c is the radius of curvature, L_i is the length of common iliac arteries, α and β are the take-off angle of the iliac arteries at the bifurcation and the angle between the abdominal aorta centerline and the plane formed by both iliac arteries, respectively. (B) An isometric view of the referent normal aortic geometry. (C) Baseline AAA geometry in XZ- and YZ-planes; L* is the length of geometrical variations field, CS0-8 are cross-sectional planes formed by dividing field of geometrical variations into eight sections longitudinally. (D) An isometric view of baseline AAA geometry and depiction of geometrical input variables; t is the thickness within the aneurysmal sac, Dia. is the maximum transverse outer diameter of the aneurysmal sac, Cir. depicts the circumferential extent of the aneurysmal sac, Tort. indicates the tortuosity in XZ and YZ-planes, Axi. and Loc. are the axial extent and the longitudinal location of aneurysmal sac, respectively.</p

Predicted von Mises wall stress.

<p>Computed von Mises wall stress distributions for (A) referent normal aorta and (B) baseline AAA simulations.</p

Effects of AAA mechanical properties.

<p>PWS (black) and AWS (grey) are computed over isolated variations of defined AAA mechanical properties, including (A) μ, (B) k₁, and (C) k₂. In all cases, hollow square markers indicate the baseline AAA values.</p

Effects of AAA geometrical properties.

<p>PWS (black) and AWS (grey) are computed over isolated variations of defined AAA geometrical properties, including (A) axial extent, (B) circumferential extent, (C) maximum sac diameter, (D) sac location, (E) wall thickness, (F) tortuosity in XZ plane, and (G) tortuosity in YZ plane. In all cases, hollow square markers indicate the baseline AAA values.</p