Warren Ellis introduced the Extremis concept to Iron man in a 6-issue story arc starting in January 2005. This arc changed Tony Stark from a cyborg to a posthuman by introducing nanotechnology into his body and altering his physiology to include direct connections with the Iron Man suit. Ellis introduced many concepts and characters that were used in the Iron Man movie trilogy, especially Iron Man 3.

If you're into superhero comics, this is a short arc you don't want to miss. It's available on Marvel Unlimited or through Amazon. In typical comic-book style, it takes some complex scientific breakthroughs and turn them into a magical elixir, yet it brings many of the reasons we research posthuman adaptation into perspective given Stark's need to deal with the story villains. And there are a few great conversations in which characters wax philosophical about their Frankensteinian need to create a future that might be more monster than they would like.