US Patent 7205002 - Selenium picoparticle

http://www.freepatentsonline.com/7205002.html

Selenium is toxic in large doses but can provide some therapeutic applications in small doses. This patent gets the record for the smallest possible dose. Claim 1 reads:

1. A composition comprising: elemental selenium (Se(0)) particles having a diameter of 0.4 to 1 nanometer; and a pharmaceutically acceptable delivering medium.