Fig. 3

Mechanical characterization of the GelMA composite hydrogels. (a) Digital images of the compressive process (a. initial state; b. 50% compression; c. 90% compression; d. recovery). b Compressive stress–train curve of different GelMA composites. f, g Digital images of GelMA composite hydrogels before and after the compressive test. h, i The cyclic compression tests with ten cycles up to 50% strain. j Digital images of the real-time compressive process. k The compressive modulus of different GelMA composites. Data are expressed as mean ± SD (n = 4). (*p < 0.05, **<0.01, **<0.001 compared to GelMA)