Figure 2.

Matrix stiffness and adhesion exert a positive effect on bone marrow MSC transfection. (A) SOX9 overexpression 48 h after encapsulation of pDNA-transfected cells within the IPNs. Gene expression levels were normalized to GAPDH and presented as relative to the levels in 2D transfected cells before encapsulation. One-way ANOVA with a Tukey’s post-hoc multiple comparison test was performed to compare SOX9 expression levels to the levels in transfected cells before encapsulation (++P≤0.01, +++P≤0.001, n=3) and between the IPNs (**P≤0.01, n=3). (B) SOX9 expression 48 h after pDNA transfection within the Gene-activated Matrices (GAMs). Gene expression levels were normalized to GAPDH expression and compared to the levels in MSCs before encapsulation. One-way ANOVA with a Tukey’s post-hoc multiple comparison test was performed to compare gene expression levels between the GAMs (***P≤0.001, ****P≤0.0001, n=3). (C)MSC morphology within the IPN set (F-actin in green, nuclei in blue). Scale bar = 25 μm for all the images. (D) qRT-PCR quantification of Cyclin D1 (CCND1) expression 48h after pDNA 3D transfection. Gene expression levels were normalized to GAPDH and expressed as log₂ (ΔCts). The dotted line represents log₂ (ΔCt) = 1, and is used to highlight the GAMs with higher CCND1 levels. One-way ANOVA with a Tukey’s post-hoc multiple comparison test was performed to compare gene expression levels between the GAMs (*P≤0.5, n=2). GAMs are described by their stiffness and collagen:alginate w:w ratios (1:1 to 1:10).