LAUSR

Cellular microstructures form naturally in many living organisms (e.g., flowers and leaves) to provide vital functions in synthesis, transport of nutrients, and regulation of growth. Although heterogeneous cellular microstructures are believed to play pivotal roles in their three-dimensional (3D) shape formation, programming 3D curved mesosurfaces with cellular designs remains elusive in man-made systems. We report a rational microlattice design that allows transformation of 2D films into programmable 3D curved mesosurfaces through mechanically guided assembly. Analytical modeling and a machine learning–based computational approach serve as the basis for shape programming and determine the heterogeneous 2D microlattice patterns required for target 3D curved surfaces. About 30 geometries are presented, including both regular and biological mesosurfaces. Demonstrations include a conformable cardiac electronic device, a stingray-like dual mode actuator, and a 3D electronic cell scaffold. Description Rational inverse design of 3D shapes Nature has a wide range of tools for making cellular microstructures, such as those found in flowers, leaves, and other biological tissues. Despite advances in printing techniques, patterning porous, curved surfaces can be challenging. Cheng et al. developed an inverse design method to achieve complex three-dimensional (3D surfaces through a subset of 2D films that are bonded together. Analytic modeling and computations to inverse design the 2D patterns allow for control of the final porosity. A wide range of examples are provided, including changes in the sign of the curvature. These structures can be fabricated from silicon, metals, chitosan, and polymers. —MSL Microlattice designs enable rational assembly of 2D films and functional devices into desired 3D curved mesosurfaces.