List three new materials chemists have developed that have medical applications

Three materials that chemist have developed in terms of medical applications are:

Artificial hips and knees in which will help people to replace injured or broken hips and knees, the plastic tubes that will serve as a replacement with the arteries that have been diseased. Another thing are the plastic skins, in which is used when skin cracks  and it allows the skin to heal itself.

answer; i believe the answer is hydraulic action;