Magnetic decoupling as a proofreading strategy for high-yield, time-efficient microscale self-assembly.

Life thrives due to its remarkable ability to create complex structures through the self-assembly of proteins, nucleic acids, and other biomolecules. Achieving such complex assemblies with the same level of fidelity, reproducibility, and advanced functionality in synthetic systems, however, has remained a grand challenge. One outstanding problem is the presence of parasitic products and long-lived intermediate states that slow the reaction process and limit the yield of the final product. Biology overcomes this challenge by proofreading to recognize and disassemble parasitic products. Such local checks, however, are currently difficult to implement in available self-assembly platforms. Here, we overcome this challenge by implementing a proofreading mechanism in a self-assembly platform. Specifically, we design intermediate states that strongly couple to an external force but a final product that is decoupled and thus highly stable to external driving, such that application of external forces selectively dissociates parasitic products. To implement this idea, we introduce lithographically patterned magnetic dipoles and an applied magnetic field to drive an assembly process similar to thermal self-assembly, but with additional controls. By applying patterns of magnetic driving that selectively destabilize parasitic states, we effectively implement a proofreading strategy to enable high-yield, time-efficient self-assembly. This realization of a general proofreading mechanism bridges the gap between artificial and biological self-assembly, paving the way for advanced self-assembled materials, with applications in next generation responsive materials, biomimetic devices, and microscale machines.