To the best of my understanding, the correct terminology for materials that can
be inserted into the human body without ill effect is 'biocompatible.' The
materials don't aggravate a response from the immune system, as well as
obviously not being poisonous. Good examples would be cobalt chrome molybdenum
alloys, titanium, or alumina ceramics in hip joint prosthetics, for example.
I have always thought that 'biomaterials' on the other hand refers to the
materials of which living systems are made, such as wood, bone, nacre and
muscle.
Most of the biocompatible materials used in medical applications are not
particularly 'biomimetic' in that they don't mimic the performance of natural
materials or structures. There is no known example of a living organism
utilising pure metals for structural stiffness, for example.
It wouldn't surprise me at all to see both fields covered in the same journal,
however. Returning to the hip replacement example, designers need to understand
the performance of cortical and cancellous (spongy) bone (a biomaterial) well
in order to design replacements of titanium or ceramics (biocompatible
materials).
Biomimetics in material design has appeared in this example as it has become
clear that the performance of bone in (say) the femur is far superior to the
best mechanical replacements made of titanium. Living bone lasts longer
(essentially forever) under cyclical loading, while good hip replacements now
last 10-15 years before wear and fatigue become problems. Mimicking the
performance of bone in other materials is highly desirable for all kinds of
applications.
There is also a lot of interest currently in creating materials that compare
well with muscle for actuators; we want a biomimetic material to mimick the
performance of muscle (a biomaterial.) If this were biocompatible, then we
could consider putting it inside the human body (e.g. as an artifical heart.)
My two cents!
David Roylance
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