Superstrong and tough DNA bulk fibers via metal ion-induced multiscale engineering

The impressive mechanical properties of DNA molecules play important physiological and pathological roles, which arise from their intrinsically ordered and periodic double-helix structures. Nevertheless, bulk fabrication of DNA-based materials that inherit their nanoscale mechanical strength remains a grand challenge. Here, we developed a multiscale engineering approach to assemble with highly ordered DNA bulk fibers. We found that the involvement of metal ions enabled tunable assembly and orientation of DNA-metal ensembles ranging from molecules to nanobundles and to macroscale filaments. This strategy remarkably enhanced the mechanical performance of DNA fibers with the optimal tensile strength and toughness reaching to 513 MPa and 130 MJ m3 , respectively, which outperform even partially protein- and polymer-based fibers. We further demonstrated the high scalability of this method by continuous spinning of 1,000 m of robust fibers with 50 mg DNA, which shows great promise in translations of DNA-based materials in mechanobiology, bioelectronics, and beyond.