Metal or plastic bone replacements are far from ideal. Under the strain of everyday life they gradually work loose within the joint, and their artificial composition may trigger rejection by the body's immune system. But now, a team at Oxford University, led by Dr Jan Czernuszka, have developed a material which mimics living bone. The breakthrough came when materials science student, Karen Clarke joined the team. She suggested that adding amino acids to a mixture of collagen and calcium phosphate that the team were working with would encourage the two to bind. Clarke's idea worked so well that the team patented it, and she went on to win two research prizes before even graduating. The imitation bone can be moulded to shape, proves resistant to stress and would not be rejected by the body. The imitation bone has many potential uses including joint replacements, healing of fractures and cosmetic surgery.