New Body Parts

I find the idea of permanent physical injury (like losing a body part) to be pretty scary, so I always enjoy reading about being able to replace damaged body parts one way or another.  There are two general ways I can think of to go about this: replacement with machinery and replacement with organic parts.

Replacing a missing body part like an arm with a mechanical one is obviously pretty challenging.  The machinery needs to be light (and I would assume need a power source) and would ideally work just like a normal arm, responding to mere thought.  I was pretty excited when I found this TED talk a while back about prosthetic arms.  The researchers are working to make light mechanical arms that provide an array of different motions and respond to a person's thoughts.  And, maybe best of all, they've had success in the lab with patients being able to feel sensation through their new prosthetic arms.  Here's the full talk:

http://www.ted.com/talks/todd_kuiken_a_prosthetic_arm_that_feels.html

Unfortunately, there's a lot we don't know about the brain.  That makes it hard to make artificial body parts that can communicate with our brains.  One group of researchers, however, has been working to overcome this obstacle in blindness.  As we all know, our brains communicate with the rest of our bodies through small electrical signals.  External signals, such as photons of light or sound waves, need to be converted by our bodies to electrical signals so that our brains can interpret them.  This is called transduction.  Since transducers are pretty common in our every day lives (e.g. microphones converting acoustic sound to electrical signals or speakers converting electrical signals to sound), the concept isn't entirely foreign.  These researchers focused on creating a device that can encode light into a pattern our brains can understand and then transduce the code into an electrical signal that can actually be sent to the brain.  It's obviously not ready for large scale human use (or probably even human use at all), but the results they were able to get are pretty amazing.  Full talk:

http://www.ted.com/talks/sheila_nirenberg_a_prosthetic_eye_to_treat_blindness.html

Like I said at the beginning, the option aside from mechanical body parts is using actual tissue.  Organ transplants are pretty common these days, but matching is an issue (as is rejection).  There have also been attempts at transplanting things like hands, but the results haven't been amazing.  It's certainly progress, but a line of research that interests me a lot is growing a person's own cells over existing scaffolding.  Or, better yet, to build an entirely new scaffolding and then cover it with cells.  The cells used are the person's stem cells.  One article I read last year was about a team of doctors treating a man with throat cancer.  They did a 3D scan of his trachea and built a new scaffold, then covered that with stem cells.  Since it uses the man's own cells, there is zero chance of rejection and he'll never need immunosuppressants to keep his body from attacking it.  Here's one article that talks about the procedure:

http://singularityhub.com/2011/07/09/in-medical-first-doctors-implant-lab-grown-synthetic-trachea-into-patient/

A lot of work is being done in this area.  Eventually, we'll be able to replace a person's heart or lungs with a perfect match made from their own cells.  And in the case of the patient in the article, when his tumor didn't respond to extensive chemo and radiation, they just took the organ out and replaced it.  With no need for transplant donors and matching lists, survival rates for lots of cancers would likely go up if we had the ability to readily synthesize any organ.