Fig. 8
Percentage of area covered by differentiated MSCs ‒observed by positive Alizarin Red S staining‒ after 14 and 21 days of inductive osteogenic culture. Results were obtained for the comparison of (a) LAR microtopographies on the different substrate tested, i.e., sPDMS, hPDMS, PMMA, and (b) the presence of ME nanotopography, exemplified in both cases with LAR HPA-including microtopography (right). Scale bars: 100 μm. (c) OCN and OPN proteins expression in MSCs cultured onto the different substrates for 21 days under inductive osteogenic induction were quantified from immunofluorescence images and expressed as mean ± SE of arbitrary fluorescence units per cell. The results were analyzed to evaluate the influence of polymeric substrate stiffness—specifically hPDMS and PMMA—and the presence of ME nanotopography on cellular osteogenic differentiation, also in hierarchical combination with micron-sized topography (in this case LAR HPA). Representative fluorescence images are shown for OCN (first row) and OPN (second row). One-way ANOVA followed by Holm-Šidak post-hoc test. Significant differences were established by asterisks (* p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001) and non-significant (ns) for the corresponding comparisons. Scale bar: 50 μm.
