**4.5 Biological properties**

Nanocomposites can be a part of the living organisms present in this diverse biosphere. The materials used must be structurally, biologically, physically, chemically, and mechanically compatible with the surrounding tissue. Since the mechanical properties are mainly affected by the elastic modulus, the transfer of load, durability, and higher strengths are of particular interest. Metals, polymers, and ceramic composites are approved for the synthesis of the required materials. Some examples of polymer filling compounds are given below:

