Titanium...

In 1952, Per-Ingvar Branemark, a Swedish doctor was studying how bone marrow produces new blood cells. His study subject were rabbits, and to watch this production directly, Branemark had made small openings in the femurs of rabbits and covered the opening with an paper thin titanium “window”, which was transparent to strong light. Once the observation was completed, Branemark, wanted to remove the expensive titanium and use it on other rabbits. But when he tried to remove the metal, he realised that it would not budge and had steadfastly bound to the bone. The same thing repeated in his other experiments, titanium always bound tightly to the rabbit’s femur. An idea dawned on Branemark, which made him forget his blood cell study and revolutionised the field of prosthetics. Doctors had always wanted to replace broken limbs and bones of people with something reliable. Despite all efforts, no one was able to integrate metal or wood into the body, because the immune system rejected any such attempts. Whether it was gold, Zinc, magnesium or chromium-coated pig bladders, the blood cells always surrounded the foreign matter and wrapped it with fibrous collagen. Within a few months of implantation, the new appendage would be covered in collagen and slip or snap free. Yet, Branemark found that some reason titanium, was ignored by the blood cells and triggered no immune response. It also fooled the body’s osteoblasts or bone forming cells, into attaching themselves to it as if there was no difference between the two. Since 1952, titanium has been used for implanted teeth, screwed on bones, replaceable hip sockets and many more other body parts.