Main Question or Discussion Point
Is it possible to 3d print a neuronal structure with a different material than neurons that would work just like a neuron with membrane potential?
Hmm, how else would you go about producing a structure like this?Neurons are micro-scale cells (in most axes). As far as I'm aware 3D printing is not capable of that sort of resolution. Further more neurons are dynamic, they have to be able to change in response to their environment. No only do they have to alter synaptic strength but be capable of metabolism, self repair, growth etcetera. A purely static object won't be "just like" a neuron.
Nerves themselves need to adapt on the basis of the signals they transmit. Prosthetics that try to interface with the nervous system do so in a variety of ways but mainly use electrodes to detect when the peripheral nerves are firing and processors to decode this and turn it into movement. There are various reasons as to why this hasn't led to a perfectly functioning prosthesis, from what I've read it's not just a problem of resolution (being able to interpret all the signals) or decoding (turning those signals into prosthetic movements) but also providing feedback. This paper reviews some of the models in which prosthetics can try to provide sensory feedback to the user so that A) they are not overburdened by having to visually control their prosthesis and B) have a healthier relationship with their prostheses:Can't you get a material similar to neuron that is capable to transmit signal? I mean for a synthetic limb you wouldn't need self repair and growth if you get the right material. The brain plasticity can get a bit tricky but the brain eventually becomes static. The material does not need to behave like a cell, it just need to have a membrane potential for transferring ions.
To get pretty close to a real limb it not only has to be able to move in all the ways a human limb can but also provide sensory feedback and be able to interpret signals from the nervous system to such a high degree that dexterous movement is possible. All big challenges.Once they work out the senses, they still need to provide the sort of muscle contraction like this for the prosthesis. This got me worried as to if it would become a technical issue. But after all, the arm is just consisted of muscle, bone, nerve, sense of touch and pain. Once they get muscle contraction to work it should come pretty close to being a real limb.
What paper are you talking about? A synapse is the junction between two nerve cells, making an artificial one doesn't immediately make good prosthetics possible. Better interfacing with the nervous system for both signal interpretation and feedback are important. It's also worth noting that in event of trauma nerve cells die off and retract. If your arm has been severed the nerves that did connect to your fingers don't just stay there waiting for a job to do. They die off. Persuading cells to regrow is an active area of research, though I'm not aware of any nerve guidance conduits being used in prosthetic research.There should be a working carbon nanotube synapse by now right? Most of it is in the thesis paper by 2011 and 2013.