Planta gold nanoparticle manufacture

A method for manufacturing a plurality of gold nanoparticles in a plant seedling germinated from a plant seed, wherein the plant seed is an alfalfa plant seed, the method comprising:

• planting the plant seed in a first soilless medium, germinating the plant seed in the first soilless medium in a growth chamber for fifteen days to form a plant seedling, removing the plant seedling from the first soilless medium, washing the plant seedling, contacting at least roots of the plant seedling with a second aqueous soilless medium comprising KAuCl4, and providing an average photosynthetic active radiation (PAR) to at least aerial parts of the plant seedling during a fifteen-day period of time sufficient for formation of a plurality of gold nanoparticles in at least a portion of the plant seedling;
• thereby manufacturing the plurality of gold nanoparticles in the plant seedling;
• wherein the plant is subjected to an average PAR, temperature, and a pH of the second aqueous soilless medium so that a majority of the plurality of gold nanoparticles have either an essentially uniform size or an essentially uniform shape.