University of Maryland scientists have developed a process to harden wood, making it a "renewable alternative to steel and plastic." Wood that's been hardened with the process can be used to make a wooden table knife "nearly 3 times sharper than most commercial table knives" and a wooden nail that's "as functional as a steel nail with comparable performance."
From Oddity Central:
A common material used in construction, wood falls short in terms of toughness when compared to human-engineered materials because it only consists of 40%–50% cellulose, with hemicellulose and lignin being weaker components. To create their hardened wood, scientists set out to eliminate the weaker components while not affecting the cellulose.
Teng Li and his team achieved their goal through a two-step process. The first step involved removing the lignin, a process that apparently makes the wood soft, flexible, and somewhat squishy, while the second stage involved applying pressure and heat to the chemically-treated wood to remove any water and densify it. At this point, the hardened wood can be processed and carved into any shape, but it can also be coated in mineral oil to extend its lifetime. Because cellulose tends to absorb water, the mineral oil preserves hardened wood knives, ensuring that they remain sharp after repeated washing.