Figure 4.

Characterization of hydrogels. (A) SEM images of GelMA and GelMA-Zn/Si hydrogels. (B, C) Comparison of the pore size and porosity of hydrogels. (D) Comparison of the swelling ratio of GelMA and GelMA-Zn/Si hydrogels. (E) Degradation of the GelMA and GelMA-Zn/Si hydrogels. (F) Typical images of the compression test process. (G) Typical compression stress–strain curves of the hydrogels. (H) The compressive modulus (15%– 25% strain pressure) of different hydrogels. (I) G′ and G′ at an angular frequency of 1 Hz at 25°C. (J) Apparent viscosities of hydrogels under steady shear from 0.1 s⁻¹ to 100 s⁻¹ at 25°C. (K) G′ and G′ under steady angular frequency from 0.1 rad/s to 100 rad/s and an oscillatory strain of 5% at 25°C. (L) GelMA-Zn/Si hydrogel can release biologically active ions within 7 days. *P < 0.05, ***P < 0.001. N = 3 for each group. All the analyses in (B), (C), (D), and (H) were performed with an unpaired two-tailed t-test. The analyses in (E) were performed with two-way ANOVA.