Dear David Roylance,
You can find the accepted definitions for biomaterials in "Definitions
in Biomaterials", Progress in Biomedical Engineering, 4, Proceedings of
a Consensus Conference of the European Society for Biomaterials,
Chester, England, March 3/5. 1986, edited by D.F.Williams, institute of
Medical and Dental Bioengineering, University of Liverpool, Elsevier .
Regards,
Mihai CHIRITA
Ph.D. Professor
Head of Biomaterials Chair
Medical Bioengineering Faculty
Medicine and Pharmacy University
Str.Universitatii 16, Iasi, 6600, ROMANIA.
Fax.: + 40-232-230614
Mobile: +40-723-533393
E.mail: [log in to unmask] [log in to unmask]
-----Original Message-----
From: Engineers and biologists mechanical design list
[mailto:[log in to unmask]] On Behalf Of David Roylance
Sent: 29 decembrie 2003 00:59
To: [log in to unmask]
Subject: Biomaterials, biomimetic materials, biocompatible materials
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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