Fig. 3

Characterizations of the hydrogels. A SEM images of GH and CPGH hydrogels. B Swelling ratio of the hydrogels in PBS (n = 3). C Degradation profiles of hydrogels in PBS containing 1 U mL⁻¹ of collagenase at 37 °C (n = 4). D Rheological property of the hydrogels: frequency spectra of storage modulus (G′) and loss modulus (G″) of the hydrogel at a fixing strain of 0.5%. E Shear-thinning behavior of the hydrogels. F Compressive stress–strain curves of GH and CPGH hydrogels. G Photographs of the CPGH hydrogels that were applied on the human finger wrist during exercise