Embodiments described herein include capped nanoparticles having a nanoparticle core and at least one capping agent including a biochemical constituent of wood or a woody plant or a derivative thereof functionally associated to the nanoparticle core. Some embodiments provide for wood products and wood treatment compositions including such capped nanoparticles, and methods for preparing and using such capped nanoparticles to produce treated wood or treated wood products.