• Question: How do you make an artificial limb or organ?

    Asked by PhysicsIsTheBest to Andrew, Lizzie, Nick, Sonia on 21 Jun 2015.
    • Photo: anon

      anon answered on 21 Jun 2015:

      With great difficulty. Each organ has developed over millions of years to perform a certain function. For example the heart is a pump with 4 chambers. pumping dehydrogenate blood to the lungs it then returns the oxgenated blood from the lungs and then pumped to the rest of the body. There are a number of safe guards, the heart muscle beats a a natural frequency without any external input. So if for some reason there is missing signal from one of the nodes – bunches of nerve fibres which regulates your heart beat depending on your activities and demand for oxygen. These nodes also have a natural beat frequency so if it does not receive any signal from the brain. So these systems and subsystems can keep you alive and keep you heart beating in case you are incapacitated in someway.

      We cannot mimic this very easily artificial hearts come on a variety of designs some try and mimic the 4 chambers and is driven by compressed air. Others are small turbines – bit like a very small jet engine. None have the save guards mentions they trail quite large power sources. And artificial hearts are a stop gap until the recipients get a transplant.

      Similarly with kidneys we have one is a spare. A dialysis machine is a a large complex set of filters and pumps, and takes many hours to clear the blood of impurities and toxins. This of us lucky enough to have healthy kidneys do not need to undergo dialysis 3 or 4 times a week.

      We have not been able to replicate lungs yet.

      Limbs have advanced greatly from the Long John Silver days. Where modern materials such as carbon fibre man light and strong limbs. Improvements in battery technology, sensor technology and computing power has made artificial limbs move much more like the natural counter part. Including giving back the sense of touch to artificial limbs.

    • Photo: Elizabeth Kapasa

      Elizabeth Kapasa answered on 22 Jun 2015:

      Well there has been work decellularising organs from animals or cadavers. Some are clinically approved too. See here:
      http://www.tissueregenix.com/what-we-do#woundcare-and-dermis

      There has also been work on whole hearts which is pretty incredible!
      http://www.nature.com/news/tissue-engineering-how-to-build-a-heart-1.13327
      http://ideas.ted.com/a-ghost-heart/

    • Photo: Andrew Phillips

      Andrew Phillips answered on 24 Jun 2015:

      This is the big challenge! It is possible to transplant organs, but there is the possibility of them being rejected. If everyone were an organ donor there wouldn’t be the shortage that we currently have.

      There has been some success with removing all of the living tissue from organs and seeding the remaining structure with cells that won’t be rejected by the patient, although I’m not sure if that is really making the organ.

      For prosthetics these are made out of materials that we can manufacture, like plastic, metal, silicon and carbon fibre, rather than biological tissues like bone. Implants are similar.

      I think the challenge is to make something with the same structure and out of the same materials as biological tissue. These structures or scaffolds can then be seeded with cells. Engineers and scientists are getting closer and closer, but there are still a lot of challenges to solve.

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