Cell-Wall-Engineered Wood Enabling Metal-and-Adhesive-Free Cross-Laminated Timber

Lightweight structural materials that combine high strength, machinability, and sustainability are essential for next-generation construction. Wood, a renewable and low-carbon resource, offers excellent mechanical performance but remains limited by fastener stability and reliance on metals and adhesives. Here, we report a superstrong engineered wood produced through synergistic cell-wall engineering across cellular and molecular scales, enabling metal-free and adhesive-free cross-laminated timber. Pressure-controlled densification induces near-complete closure of open cells in natural beech wood, generating a dense, smooth architecture with a 3-dimensional mechanical interlocking network analogous to micro-mortise-and-tenon joints. The resulting material preserves the intrinsic anisotropic architecture of wood while forming a 3-dimensional mechanical interlocking network resembling micro-mortise-and-tenon joints. Wooden structural material exhibits substantially improved dimensional stability and mechanical performance, including a density of 1.33 g cm^-3, a flexural strength of 150.89 MPa, a compressive strength of 88.48 MPa, and an exceptional Janka hardness of 18.84 kN. Wood-derived nails fabricated from this material function comparably to steel fasteners, providing high strength-to-weight ratios while eliminating corrosion and adhesive contamination. This approach advances timber construction toward higher performance, reduced environmental impact, and improved sustainability, offering a scalable pathway for green building applications.