4D Printing of Engineered Living Materials

Herein, a method that uses direct-ink-write printing to fabricate engineering living materials (ELMs) that respond by undergoing a programmed shape change in response to specific molecules is reported. Stimuli-responsiveness is imparted to ELMs by integrating genetically engineered yeast that only proliferate in the presence of specific biomolecules. This proliferation, in turn, leads to a shape change in the ELM in response to that biomolecule. These ELMs are fabricated by coprinting bioinks that contain multiple yeast strains. Locally, cellular proliferation leads to controllable shape change of the material resulting in up to a 370% increase in volume. Globally, the printed 3D structures contain regions of material that increase in volume and regions that do not under a given set of conditions, leading to programmable changes in form in response to target amino acids and nucleotides. Finally, this printing method is applied to design a reservoir-based drug delivery system for the on-demand delivery of a model drug in response to a specific biomolecule.