Fig. 4

a1 Schematic illustration of the contraction behavior of the cultured cardiac muscle tissue on the bioinspired scaffold. The cultured cardiac muscle tissue showed a pseudo-3D structure, which could be separated into four layers, the (i-1 and -2) upper, (ii) middle, and (iii) bottom, based on aligned and random cardiomyocyte morphology. a2 obtained bioinspired soft robot with embedded Au microelectrodes. Copper wires were connected to the structure using a silver paste to make electrical contact for local electrical stimulation. a3 the mechanism of longitudinal tail displacement, which induces the soft robot displacement along the vertical direction, mainly on the tail part, when the cells contract. a4 beating response of the bioinspired soft robot when stimulated with an electrical field. Reprinted from (41), John Wiley and Sons (2022), b1 Schematic diagram of TESR system, control module, and rotary freestanding triboelectric nanogenerator (RF-TENG), b2 Schematic of crawling process of TESR based on the locomotion principle of an inchworm. b3 Working principle of RF-TENG in one cycle. b4 The application demonstrations of TESR: crawling into a horizontal and on an inclined plane. Reprinted from (44), John Wiley and Sons (2022)