In my materials engineering class we recently finished a series
of lectures discussing biomaterials. In these talks my professor talked about a
great may ways to use materials to be implanted in the human body. Most of his talks
revolved around the use of metals in the body. He also talked about ceramics
and plastics the rest of the time. For this post I would like to outline what I
learned of the course of this unit.
For hard tissue replacements and augmentations, doctors will
use ether metals or ceramics. Hard tissue would be pretty much limited to bones
and the areas around joints. A common metal used for these applications is a
titanium alloy that includes vanadium and aluminum. They use this alloy because
it is very strong and has a relatively high ability to bend. Another major
reason this alloy is used in the body is because it wound corrode inside the
body like iron would. The down fall of these applications is that metals are
very heavy and since they are so strong, they can lead to a weakening of
surrounding hard tissue. Ceramics are used because they are also very strong
and they are inert. This means they won’t react with other components of the
body that might cause problems. Because ceramics are porous, surrounding
tissues can grow into the gaps in the ceramic implant. This means that there is
no need to secure the implant with something such as screws like is necessary
with metals. Another really cool thing about ceramics is that their chemical makeup
can be made to be very similar to that of natural bone. If the concentrations
of elements in the implant are close enough to the natural bone, the implant can
actually become part of the bone structure over time. The biggest flaws with
ceramics are that they are brittle in certain applications of force and can
break in these cases. They are also very difficult to shape very accurately. Because
of these flaws metals are more commonly used to replace bone tissue.
Plastics are also used for applications in the body. Plastics
are used because they are lightweight and can be very flexible and are very
easy to shape. Scientists also have lots of ways to make different plastics to they
they can be made to fit a variety of applications. One application of plastics
in the body is artery replacements. Arteries can be replaced with a plastic
tube that is very flexible and coated with a body protein that makes it be
accepted by the body. Another application is in artificial organs such as many models
of artificial hearts, which I have talked about in previous posts. Another common
application is in the socket of hip replacements. A plastic cup is used because
the common titanium alloy scratches very easily when it rubs against other hard
materials so a plastic cup can prevent the shaving of the hip replacement.
I found this post interesting because it discusses materials being implanted into the body. Personally, implants scare me, so it was interesting to find out how many different types of materials people can have implanted. It was cool to learn what materials were bad and which ones wouldnt harm your body. I had no idea that there are such thing as artificial organs, so to learn about that was interesting as well.
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