Figure 4.

Mechanical properties and degradation behavior of PPy:PSS modified ADA‐GEL. A) Compression stress‐strain curve of ADA‐GEL, 0.1 m PPy, 0.2 m PPy, and 0.4 m PPy hydrogels. A stiffer compression response can be observed for PPy modified hydrogels. All hydrogels show a strain‐stiffening behavior. B) Quantified elastic modulus of the hydrogels. A significant increase of more than tenfold in Young's modulus is observed for all PPy modified ADA‐GELs in comparison to pristine ADA‐GEL (****p < 0.0001). Data are shown as mean ± SD. Statistical significance was assessed using one‐way ANOVA analysis followed by post‐hoc Bonferroni comparison of means. C) Degradation kinetics of ADA‐GEL and ADA‐GEL‐PPy:PSS. Swelling of the hydrogel cylinders measured by the diameter (initial diameter: 10 mm) changing over incubation time in DMEM for 3, 6, and 16 h, as well as 1, 2, 3, 7, 14, 21, and 30 days at 37 °C, 5% CO₂. The presence of the PPy:PSS matrix seems to inhibit the initial swelling of the hydrogel cylinders after 3 h of incubation. Data are shown as mean ± SD (n = 6). D) Swelling and degradation of ADA‐GEL and ADA‐GEL‐PPy:PSS measured as the mass of hydrogel cylinders recorded over incubation time. Data are shown as mean ± SD (n = 6). Short‐term swelling behavior (<24 h, Figure S4, Supporting Information) can be found in the Supporting Information.