| This thesis exhibits a body of work at the intersection of engineering, biology, chemistry and materials science. We have created miniaturized devices that will be useful to scientists, engineers, and physicians. The advances detailed here are in the use of nontraditional lithography to pattern microscale structures that self-assemble from 2 dimensions (2D) into 3 dimensions (3D). The main contributions are: (1) Folding hands-free origami using thin film stress, (2) patterning polymers for motion and folding, (3) and combining these to trigger microtools on command.;The first work involved patterning layers in 2D with different mechanical properties such as modulus and thin film stress, which then assembled into 3D structures. We achieved designs with thousands of components that folded bidirectionally, which resulted in precise positioning of metallic and polymeric elements in 3D. Hands-free origami structures were used as cell culture scaffolds, suggesting methods to build biologically relevant platforms in 3D. Using theoretical models of thin film multilayers allowed translation of paper origami to self-folding miniaturized versions of the cubic core, a stent, and the paper airplane.;The second part of this thesis focused on patterning polymers. We began by creating and studying hydrogels that moved spontaneously via rotation, translation, and precession when soaked in solvents and then placed in water. Continued work with polymer patterning led to construction of bilayer hydrogel actuators via differential swelling.;Lastly, we created metallic/polymer hybrid microgrippers that could be remotely guided and actuated via enzymes to perform a biopsy. Here, using polymer chemistry to create patternable polypeptides and polysaccharides, combined with thin film folding, allowed for triggers that folded the device on command. We explored closing kinetics with several enzyme families, and developed a more complex folding design that closed to grip and re-opened to release.;These studies demonstrate approaches to patterning objects with useful properties at a scale too small to build by hand. The miniaturized metal and polymer devices we have created answer fundamental questions about how to make small autonomous tools for medical procedures. 3D structures for studying cell behavior, and microdevices for electronic and optical applications. |
