Fig. 2: Protein-bilayer hydrogel strips constructed from (GB1)8 and (FL)8 display shape-morphing behaviors.
From: Engineering shape memory and morphing protein hydrogels based on protein unfolding and folding
a Linear (GB1)8/(FL)8 bilayer strip in air with a clear boundary between the two protein layers (upper layer: (FL)8, lower layer: (GB1)8). b The observed bidirectional bending deformations of the as-prepared (GB1)8/(FL)8 bilayer strip. The bilayer strip bent towards the (FL)8 side in PBS and bent toward the (GB1)8 layer side when GdmCl concentration was above 0.6 M. c The variation of (GB1)8/(FL)8 bilayer strip bending angle with the environmental GdmCl concentration (n = 3). The dimension of the hydrogel strip is 12 mm in length and 3 mm in width. d Reversible bending of (GB1)8/(FL)8 bilayer hydrogels with the environment switched between in PBS and in 7.0 M GdmCl for seven cycles (n = 3). e The bending angle of (GB1)8/(FL)8 bilayer hydrogels varied with the layer thickness ratio (n = 5). f The bending angle of (GB1)8/(FL)8 bilayer hydrogels varied with the protein concentration of the (FL)8 layer. (FL)8 concentration was varied from 10 to 20% while (GB1)8 concentration was fixed at 20% (n = 3). Statistical significance was evaluated by using the Student t test. Significance levels indicated by asterisks: ***P < 0.001, **P < 0.01, *P < 0.05. The error bars in (c–f) are standard deviations.
