Untethered micro-robotic coding of three-dimensional material composition

• DOI: 10.1038/ncomms4124
• Publication Date: 2014-01-28T13:12:14Z
• Authors: S. Tasoglu; E. Diller; S. Guven; M. Sitti; U. Demirci
• Keywords: directed assembly; Biocompatible Materials; Hydrogels; Robotics; 02 engineering and technology; Cells, Immobilized; coded materials; magnetic actuation; 530; micro-robotics; Article; 620; microgels; Tissue Culture Techniques; Mice; tissue engineering; Human Umbilical Vein Endothelial Cells; NIH 3T3 Cells; Animals; Humans; 0210 nano-technology; Chickens

Complex functional materials with three-dimensional micro- or nano-scale dynamic compositional features are prevalent in nature. However, the generation of three-dimensional functional materials composed of both soft and rigid microstructures, each programmed by shape and composition, is still an unsolved challenge. Here we describe a method to code complex materials in three-dimensions with tunable structural, morphological and chemical features using an untethered magnetic micro-robot remotely controlled by magnetic fields. This strategy allows the micro-robot to be introduced to arbitrary microfluidic environments for remote two- and three-dimensional manipulation. We demonstrate the coding of soft hydrogels, rigid copper bars, polystyrene beads and silicon chiplets into three-dimensional heterogeneous structures. We also use coded microstructures for bottom-up tissue engineering by generating cell-encapsulating constructs.