In fifty years, standard-issue supersoldiers will boast exoskeletons that make bullet-proof vests obsolete. In fact, at the rate researchers are figuring out bone synthesis, you could have an exoskeleton even sooner than that. Using substances called "hydrogels" (pictured), tissue engineers create a thick, flexible scaffold where cells can thrive and grow. Now Carnegie-Mellon scientists have made a breakthrough, using hydrogels to generate bones as well as soft tissues. That means people could regrow bones and create new bony structures where they didn't exist before. According to Science Daily:
Hydrogels, which are considered to be the state-of-the-art in tissue design, are made from polymers that swell in water to form a gel-like material. They interact with growth factors much like demineralized bone matrix does, providing scaffolding for bone cells to proliferate and form new tissue.
Seems obvious that after this bone-growing scaffold is perfected for treating injuries that it would become the body modder's dream substance. People could grow Hellboy horns, protective chest plates, or foot bones that could withstand a lifetime of high-heeled shoes. Hydrogels Provide Scaffolding for Growth of Bone Cells [via Science Daily]