There not much I could do for research on this, but it is a rather simple question with possibly a complicated answer.
In Justice league Victor Stone (Cyborg) shoots a missile out of his arm that is constructed from the material that he is made of. Now considering that he is a Cyborg this is entirely an acceptable scenario.
But, what I want to know is how he regenerates that lost material?
Being that the comic Victor Stone (Cyborg) consists of nanites and robotics, do the nanites reconstuct the matrial lost or is it a more magical process?
So how does Victor Stone (Cyborg) regenerate that lost material?
I don't mind an answer from any DC universe.