Multi-State Hydrogel Device Programmed by DNA Sequence Instructions

Living systems can convey information and drive complex chemomechanical processes such as metamorphosis using biomolecules as signals. Yet, synthesizing macroscale soft structures that can likewise interpret and respond to such signals by undergoing chemomechanical changes has been challenging. Here, we create a new family of programmable polymeric materials, DNA polymerization gels, whose shape change can be programmed by DNA sequence instructions. The growth and shrinking of these DNA polymerization gels are driven by the polymerization and depolymerization of DNA via hybridization chain reactions. The actuation mechanism was studied in-depth for optimized sequence design to perform high-degree growth and reliable reversibility. We developed a multi-step photolithography process that enables the fabrication of centimeter-scale gel devices consisting of multiple micro-segments. Several orthogonal DNA systems that can selectively execute “grow” or “shrink” instructions were designed to direct material transition repeatedly between different configurations. Finally, we introduced a machine learning-assisted design method for creating “seed” structures, which in response to different DNA instructions, could transform into one of a large set of functional target configurations: four different letters and either every even or every odd Arabic numeral. Our work offers a general architecture for manipulating polymeric materials by dissipative chemical cycles, programming functions into the structures by molecular designs, and encoding complex, continuous transformations of curved mechanical structures into precise molecular instructions and protocols.