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While David's comments have some merit, it is worth nothing that modern usage of the term "biocompatibility" acknowledges that implantation of any device (of synthetic or natural origin) will engender changes in both the material and the host. We consider a material to be biocompatible *in a given situation* if the host and material reactions are acceptable in the context of the many patient-related factors.
I would add that the development of synthetic implants is fading very rapidly from the biomaterials research agenda, now almost wholly replaced by regenerative strategies (previously aka "tissue engineering") aimed at a fully healed native structure. Is there a role for biomimetics in here? Perhaps in developing scaffolding that has a near-native nanostructure that will encourage appropriate phenotypic expression in implanted or ingrowing host cells. However, titanium total hip components informed by biomimetic design is no man's land.
Mike Lee
>===== Original Message From Engineers and biologists mechanical design list
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>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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