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. Author manuscript; available in PMC: 2020 Mar 1.
Published in final edited form as: Biomaterials. 2019 Jan 8;197:101–118. doi: 10.1016/j.biomaterials.2019.01.009

Figure 4. Increased cell protrusion generation and preferential protrusion orientation in aligned vs. unaligned matrices for HFF and U87 cells.

Figure 4.

(A) Representative images of HFF cells embedded in an aligned and unaligned Matrigel matrix containing colloidal particles conjugated to fibronectin. Images show detailed morphology of cells with measured protrusion lengths and protrusion angles. (B) Protrusion length (mean ± standard deviation) of HFF cells as a function of matrix alignment status and colloidal particle ECM protein conjugation. Average protrusion length in Matrigel lacking colloidal particles is also shown. ****, p<0.0001 by Sidak’s multiple comparisons test following two-way ANOVA. (C) Relative frequency distribution of the angle between HFF protrusions and nearest neighbor fibers (left panel) and in unaligned matrices (right panel) for Matrigel matrices containing colloidal particles conjugated to human fibronectin, tenascin C, laminin, or BSA. Protrusion direction distribution in Matrigel lacking colloidal particles is also shown. For each cell type, matrix alignment status, and nanoparticle ECM protein, 20 protrusions were measured from a single 3D matrix. (D) Representative images of U87 cells embedded in an aligned and unaligned Matrigel matrix containing colloidal particles conjugated to fibronectin. Images show detailed morphology of cells with measured protrusion lengths and protrusion angles. (E) Protrusion length (mean ± standard deviation) of U87 cells as a function of matrix alignment status and nanoparticle ECM protein conjugation. Average protrusion length in Matrigel lacking colloidal particles is also shown. *, p<0.05; **, p<0.01; and ****, p<0.0001 by Sidak’s multiple comparisons test following two-way ANOVA. (F) Relative frequency distribution of the angle between U87 protrusions and nearest neighbor fibers (left panel) and in unaligned Matrigel matrices (right panel) for matrices containing colloidal particles conjugated to human fibronectin, tenascin C, laminin, or BSA. Protrusion direction distribution in Matrigel lacking colloidal particles is also shown. For each cell type, matrix alignment status, and nanoparticle ECM protein, 20 protrusions were measured from a single 3D matrix. In panels (A,D), colloidal particles are displayed in green, F-actin in red, and the nucleus in blue. Images are maximum intensity projections of confocal slices containing aligned fibers, or of cells embedded in 3D. Scales are indicated.