A method of forming an active agent infused linear material includes passing a substantially linear polymeric substrate through a linear substrate infusion chamber in a first direction, flowing a liquid infusion solution through the linear substrate infusion chamber in a second direction, and contacting the linear substrate with the liquid infusion solution at an infusion temperature and for an infusion time effective to infuse the one or more active molecules into or onto a surface of the linear substrate, thereby forming an active agent infused linear material. The liquid infusion solution includes one or more active molecules. The second direction is substantially opposite or substantially parallel to the first direction. A linear substrate infusion system and a polymeric linear substrate are also disclosed.