Indirect 3D and 4D Printing of Soft Robotic Microstructures

The development of 3D soft-robotic components is currently hindered by material limitations associated with conventional 3D printing techniques. To overcome this challenge, an indirect 3D printing approach based on the fabrication of 3D printed sacrificial templates is proposed. High-resolution micromolds produced by direct laser writing are infused with polymers and then dissolved, leading to the final 3D printed soft microstructures. This method is used to indirectly print 3D and 4D soft microrobots. The versatility of this technique is shown through the fabrication and actuation of gelatin helices filled with magnetic nanoparticles. In addition, it is shown that stent-like microstructures with shape memory properties can be manufactured with minimum features of 5 µm, which is 40 times smaller than those reported to date. In summary, the utilization of this technique can overcome obstacles associated with the fabrication of soft microrobots and surgical tools for minimally invasive surgery.