Figure 1.

(a) Schematic description of the preparation of the biological machine (Bio-bot) by self-folding. (b) Schematic diagram illustrating the design of the radius of curvature for multi-layered hydrogels. The radius of curvature is predicted using the heat-induced bimetallic strip equation, with mechanical properties as the expansion ratio and elastic modulus of each layer. (c) Image depicting the radius of curvature of the multi-layered hydrogel, formed larger than the intended radius of curvature.