I've heard of 3D printed ears, limbs, and muscles. I assume if you were to attach one of these ears to a person, it wouldn't have a sense of touch and other properties that a real ear would have. So which properties of real human parts does 3D printing allow and which properties is 3D printing not capable of reproducing using current technology. And how do you predict those technologies will change in the future to further improve 3D printing?
Also can someone explain how human cells can be printed? Would this involve some kind of cell-plastic filament? How would the cells survive, etc. Where would you get these cells from and how would you be able to go from using a 3D printer to layer these cells together to then forming an organ out of that?