Creating bioproof, flexible wiring for the body

Okay, so conductive tattoos seem to be out because of the body's natural conductivity and the only available solutions' high level of resistance before tattooing.  Which leaves me with a question: how should we make bioproof wiring?

Basically a proper subdermal wire seems to need 3 things:
  • some flexibility
  • bioproofing
  • a small size
Here's my proposal: get some thin tissue paper.  Stitch a zigzag pattern on it out of conductive thread.  Take that and coat it in some type of flexible bioproofing material (what are the options?).  Give it a tug to break the paper inside, and then you have a stretchy biocompatible wire ready to be run under the skin.

Anyone have any better ideas?  One that would make a more compact wire for the body suitable for running all over?


  • better idea: buy some

    all commonly used material, many available with teflon coating for insulation.
  • But using that means that it is rigid.  I did a quick test with a bit of string on top of my skin to look at how much flex I would need over the line, and I need over an inch of flexibility.  I guess I could just snake the wire around, though.  Or perhaps loop it so that moving my head or back would constrict the loop and nothing more.

    Perhaps you are right, though.  This would be far simpler.
  • if you mean elasticy rather than flexibility, you won't need much of it. just make your wire long enough so it won't hinder your maximum allowed motion, maybe adding a tad more. and that's it. if you really need more flexiblity you'd have to worry about other health issues in your body.
    but even then , you may be better off winding the wire around a thin rod , implant it, and pull the rod out. so you are left with a spiral in place.
  • I did mean elasticity.  Sorry bout that.  Your method will work, Thomas.  Thanks.
  • The more I think of this, the more I gotta say, this wount work. The wire would have to be of totally different elasticity, after you implant the wire, one move and you have several places along the wire that will tare the tissue. When you you implant something, the tissue around it eventually grows to it. One move, a lot of trauma. Thoughts?

  • That was the problem I was originally trying to solve with my zigzag approach.  I figured that would let the wire stretch with the body as much as you move.

    My next solution is to get fine wire and loop it into springs/loop de loops at key points.  The coils should shrink as I move my head/back, pulled taut by being stuck in the body.  Then just lay the line in straight.  My only fear is that being wound like that will cause the casing to break.  You think that would work?
  • A google search for 'elastic wire' brings up a couple results. These are the top two: and

    I don't know if they would be suited for use in the body, but hey, it's a start.
  • hehe. except that the first one ain't conductive wires. and the second one is, altho very bend-able, not really the kind of rubber-like elastic thing you'd be looking for.
  • edited August 2012
    If anyone finds any stretchy conductive wire, please let me know.  That would make a lot of this much easier.

    That Nitinol wire is mostly a shape memory alloy, it looks like, capable of snapping back straight after being massively contorted.  It's cool, but not necessarily what we need.

    A future project would involve running wires to my fingers, so what I really need is a very thin stretchable thing to conduct electricity.  That application doesn't need to worry as much about impedance, though I'd still need some that can carry a decent amount of current over long distances.

    So!  Alternative approaches: find another material like conductive rubber, cast it into a small wire, then coat in a flexible bioproof thing which we still need to figure out.  Any ideas?

    I'll also give wire coils a try since that simplifies life so much.

    [edit]Looks like conductive rubber is out:  1,000 ohms an inch, more if stretched.  And I think they're using thicker strands than I would.
  • I had an idea, relevant to this discussion.

    So, wire doesn't stretch. That's fine, we can work with that. How?
    What else in the human body doesn't stretch? Bones!

    So, for long runs, like down the length of the thigh, just route it next to the bone.

    Now, the tricky part. Joints.
    Joints stretch, flex, rotate... all wonderful things, all things that wire cannot do.
    How do we get around this?
    What I'm thinking is some kind of miniture spool thing. Like one of those keycard zipline thingies that holds a keycard on your waist, and lets you whip it out to open doors.
    OK, cool, we've got the extension covered. How to prevent that from getting all gunked up with bodily fluids and other fun stuff? aka - how do we bioproof this?

    So, we need something that can stretch, is bioproof, and can have wire routed through it.

    I'm thinking something like heat-shrink tubing (but not, duh. something more bioproof)
    Alternatively, and this would make it a big install, but then what full-scale wiring wouldn't be, make it like an artery. Bear with me. Think a hose of bioproof material, within which your wire, spool, and (possibly) hardware sit in. Route the hose whereever it needs to go, and hey presto.

    But seriously folks, if you're thinking of doing wires around joints, you're looking at a MAJOR install. Unless you're thinking only shallow subdermal.

  • edited August 2012
    Eh, damn, I was hoping it would be that easy.

    How about braided mesh around an elastic core? Thinly braided so as to not waste space.

    @Bish Sorry, didn't see your post until mine refreshed the page. Nice solution, but dude, that's a lot of surgery. I would totally use it for bigger stuff though- I'm quite taken with the artery idea. It's neat and it makes modular networks feasible.
  • the idea of tubing to hold multiple wires mightg be indeed a smart one. especially if you have to run multiple wires in between the same locations. altho it won't keep out body fluids or stuff. so everything would have to be bioproof anyway. which is not a big problem as both, ptfe tubing and ptfe-coatet wires are available off-shelf from BOLA,and the earlier linked shop.

    bones, joint and stuff... better stay out of those as there are nerves running close to those already. and you don't wanna cut those by accident.

    @SixEcho that elastic core does sound pretty decent. like a tiny silicone string or so. but i'd worry about it too. if it would end up beeing stretched, it would apply pulling-force on both ends, usualy pressing against, or pulling at tissue.
    so if anything, it would have to be somethin elastic that produces almost zero resistance, maybe a very soft foam.
  • @Bish: isn't that first idea basically "give your user a little bit of the kind of surgery Wolverine is supposed to have gone through? The kind people think he needed a healing factor to survive?"

    The second idea sounds far more doable.
    More generally, I will point out _anything_ stretchy is going to change resistance as it stretches.

    Jesus, I'm just shitting all over everyone tonight, aren't I? :-)
    Sorry, all.
  • Yeah, lots of surgery.
    But guys, it's wiring up the human body! There's no quick and easy way with current tech to circumvent that for large installs (I'm talking cross-joint here, so like an arm, across the knee joint, or even just a finger base to tip).
    The reason I bought bones into it was because they act like wire - they don't stretch. That's the only reason. If someone is looking to wire an area that isn't going to involve stretching across a joint (say, the thigh, or forearm) then you look for an area that isn't going to be moved much by the flexing of muscles. Hence, nest it next to bones.

    @SixEcho - Major surgery, and to be honest I kind of hope nobody here gets the idea that it'd be neat to do this at home. This is more just an idea to get around a known problem - that of stretching wire.
    @ThomasEgi, Yeah, I know bioproof wire exists, and that would definately be used, but the spool mechanism would also need to be isolated from bodily fluids so as to pay out/reel in the wire smoothly. That's why it'd be a gardenhose style of thing, with everything inside a bioproofed tube. Extra bioproofing on the wires would be wise though, in case of a breach.
    @Unqualified - Yup, when I said MAJOR install, I meant it. Re: stretchy stuff, that's why it's on a spool. The wire doesn't stretch, it just gets payed out of the spool as needed, and reeled back in when not needed. Simple! :)

    Seriously though, my money's on conductive tattoos, and I feel that's where we should focus our energy. Reasons? Cheap, easy, (comparatively) painless, no recovery time, modular (just ink up a new connection!), No network of scars (Sure, doesn't bother us, but it might get to society having people walking around with huge scar networks running all over the joint)
    ... I could go on, but I'm sure you get my point.
  • and against all reasons you listed for conductive tatoos there is one standing against them: they don't work.

    a spool is not that much of a great idea as it consists of mechanically moving parts, and also puts mechanical stress on the coating of the wires. having a few cm surplus wire just hanging around in the body (in form of a coiled up wire) makes a lot more sense.
  • I've heard some time ago of stretchable electric/data cables apparently made of a spiral wire surrounded by a braid of spandex. They have the same elasticity as the skin, minimizing the risk of rupture at the body/wire interface in case of implantation, but I'm not sure that spandex can be easily bio-proofed.
    Roboden - Elastic Electric/Data/USB Cables - Asahi Kasei Fibers
  • ThomasEgi: No offence, but,,, No testing has been done yet and I see no reason to throw the idea into the garbage can. Why say "It doesn't work"? I say let's make it work!

    Srsly no offence, I respect and like your ideas and know-how. nuff said

  • edited August 2012
    guess the spandex is only for protecting the wires from the surrounding and wouldn't be necessary for an implanted wire. which boils the rest down to the wound up wire we came up with earlier. nice to see such expandable wires tho, they are quite useful in general.

    @Ghost02236 : it is very hard based on physic laws, body chemistry, and for the actual process. it is not that it won't work at all, but compared to other options we have , the idea is not even close to be practically used. i am not throwing it into the garbage can, just saying that it is not an option for now, and that it'll be difficult to make it work.
    i am sorta focused on solutions that actually work today so we can use them to build implants and advance.
  • I agree that we need to focus on things that can be used now, like finding a good wire to go under the skin that won't take up too much room (nice find Mattias, by the way)  but that doesn't mean we shouldn't be working on building some stuff for the near future too.

    I have a feeling that, with a little thought, most of the problems we have with the tattoos will disappear.  But the only way to know the scale of the problems we have to overcome is to test.  You might be right that it is wrong.  You might be wrong, too.  We don't know yet.  But tattoos have so much potential in this field that we can't ignore them out of hand.
  • Yeah, TE, Sau's pretty much summed it up. Tattoos, whilst they don't work _at the moment_ provide the greatest flexability and use than any conductive alternative. The only catch, as you point out, is that they don't work. Yet.

    This is why I was advocating putting our developmental energies into getting a viable conductive tattoo working, because that will be the best solution.

    TE, do you disagree that, if we could get them working to a satisfactory standard, tattoos would be better than hard wiring requiring implantation?
  • well _if_ they'd work on a satisfactory standard they could be used. but even with the actual conducting working i still see a bunch of hurdles to overcome, like you can hardly rewire them, or cross 2 traces without connecting them, removing them altogether would be also problematic. i guess they would have some use, but it would be limited to special cases.
  • But what's the alternative?  Running wires underneath the skin?  Weaeing clothing with wires and induction coils sewn into it?  Wires are going to be really, really hard to install.  Right now they are the only option (why I started this thread in the first place) but there is just too much involved for any extensive modifications.  Breaking the wires outside of the body would work, but it makes implants into wearables.

    There are plenty of problems with tattooed circuits, sure, but overall I'd say that the ease of use will outweigh the problems.  We will just have to be smart with how we tattoo them, and occasionally use a short cable to cross paths.
  • the alternative.. good question. i mean routing a wire through the skin ain't that hard if you have a needle with a small hook. so you can pierce a tunnel, and pull the wire through it. so with each needle-you can make like 3 to 5 cm maybe. i'd bet there are some quite useful medical instruments available for that task, if not they could be build without too much effort.

    connecting that wire to the actual implants is what worries me a lot more. i am not aware of any tiny bioinert connector systems. and soldering inside the body is out of question.
  • You wouldn't want a firm connection anyways.  Imagine what would happen if the wire is too short, or the body grabs a section of wire while you're moving, or if somehow the wire got caught on something.  Ouch!

    My thinking so far is that we'd have to get some custom connectors mass produced for the community.  Or just find a shop willing to do small orders of tiny metalwork.  What I'm thinking are male female connectors made out of titanium, with a small magnet on the inside of the female one.  Coat most of the connector except for the last little bit of the male one and the far reaches of the female one, and you should be able to get a good connection with minimal environmental exposure.  But even if you do, we're talking titanium, so it shouldn't be a problem.  You see any problems with the idea?  That's what I'm going with so far for my connectors.
  • from my own non-implantive experience, non-firm connectors are like one of the main points of failure in electronic devices. so personally, i'd like to avoid them. there isn't much in the body that could "greb a section" of a wire. and besides, expandable wires would pretty much be the failsafe for that very case.

    firm or not, we'd need an easy of connection in-vivo.
    my idea for a DIY connector would be based on conductive silicone (regular medical-grade silicone mixed with a bio-inert conductor (like gold or metal powder).

    first would be a model of the male-connector made from a small teflon stick. (maybe 2 mm in diameter, and 8mm long or so). one would add rings of conductive silicone around that stick, one for each contact. once the rings are mostly dried/hardened, one would wrap around a wire around each contact and add a bit more conductive silicone. once that's done. add non-conductive silicone so all the rings sit firm in place. after everything hardened, pull out the teflon rod and the female connector is pretty much done (would look similar to a regular 3.5mm audio jack, just a bit smaller and silicone).

    for the male connector i am not sure yet. probably very much like a audio-connector too, maybe made from the wires just wound around a teflon rod.
    the important part would be that the female connector has a small hole on the other end, and the male connector has an extra thread that you can use to pull the male connector into the female one, and secure it with a knot or so.

    very rough illustration (excuse my 5-minute-gimp-quality)


    the thin thread from the male connector could also be used when pulling the wire through the body, as it is not electrially critical so no need to hesitate when grebbing it.

    the whole idea probably requires a lot of detail work end experimentation to turn it into a reliable connection. but it could be made at home with some practice and materials should be easy to source. one could also use an extra ring to detect if the connector is no longer in the correct position, and shutting down all data/power so one doesn't get any undesired electrical shocks.
  • I'm still in favor of nonfirm connections until we have a good source for compact stretchy wires (call me paranoid) but that seems like a workable design.  It would be great for bunching connections together in one.  How about this: a piece of crimpable metal tube cast in bioinert everywhere but deep inside.  Slide in the sire, crimp the tube down the length, and the silicone on silicone seal will be pretty tight.  Seems like that might be a bit simpler to make and use for a single connection, if it works well enough.  Yea or nay?
  • not sure. crimping requires a lot of force that might damage the silicone around it. also not sure if wileding a crimp-tool during an implantation is a great idea.
    and a single connection is of no use, you need at least 2, to get something done having 4 lines is pretty much a requirement.
    with that ring-based plug of mine we could have both, firm and non-firm connections, besides it would be 100% bioinert so even if the plug slides out there is no harm to the body. besides it allows you to insert all wires at once.

    i'd guess the extra effort of building such a connector is well worth the benefits you gain from it.
  • Alright, valid points.  I may have to try whipping up a batch of your connectors, see how they work.
  • Hey guys... anyone still playing with the idea of bioproofing the whole shebang?

    Wires, connections, nodes? Chuck it all in a bioproof hose. Problem solved. I think.
  • this won't solve the problem. you can't connect 2 implants routing wire through your body and then wrap something around the entire thing.

    nor can you put the entire setup into a bioproof shell and implant the whole thing (not without cutting open big parts of your skin (which is exactly what we want to avoid))

    so the idea is to route wires with the the smallest amount of invasion, and then connect the actual nodes in vivo. (again with least amount of tissue-damage)
    it is better to have all components bioproof to begin with, instead of relying on just a small shell.

    for a small wire-less implant, wrapping everything in medical grade silicone sure would do the trick. but this discussion is about wiring.
Sign In or Register to comment.