Subdermal Armor



  • I think it's getting a little too hypothetical and also probably deserves its own thread at this point. ;)
  • Back on the subdermal armor topic, I'm now looking at the usefulness of single-ply pieces of fabric-based armor using aramids or UHMWPE sheets. These would be thin and flexible, and provide improved resistance to laceration or punctures caused by things like animal bites, jagged metal, broken glass, etc. A small piece could be laid across the inside of the upper arm to protect the arteries and nerves there, or pieces could be put in place over the ribcage where the ribs would provide a sort of lattice of support to help the material further resist puncture (while also preventing an injury from just shoving the whole panel deeper into the body).

    Does anybody here have any input on the biocompatibility of these materials, should a bioproof coating fail? I'm talking non-injurious failure due to coating flaws or such, if an injury occurred and the armor was affected it would be removed and replaced with a new piece. These should be regarded as disposable, single-use emergency items.
  • Aramids are not biofriendly. They are actually the opposite of that.

    UHMWPE is another matter. Here is a link to basically decades of references with this stuff used in medical grade implants.

    This would be, I think, the best option in this thread so far.
  • Fantastic info, thanks Glims. Would a coating even be necessary then, if a single sheet of UHMWPE was used? It seems like as long as the fabric is indeed just UHMWPE and no weird surface treatments were applied to it, it might be inherently biocompatible and safe for implantaiton as-is (after sterilizing).
  • edited February 2015
    I hate saying this but... that should be ok.... 

    strips of course. and sterilized.

    The implantation is you biggest issue. That much open is going to be rough.

    C'mon down man :) we have a clean room. One of us will do that for you...

    EDIT: and then one month of healing and then we test it.
  • So we use him as a sling shot target? :P
  • I'm thinking the implantation would be similar to getting any of the many silicone subdermal cosmetic implants out there, at least in terms of technique. Might be a little tricky for the implanter, what with the fabric being so thin and flexible it will probably not want to just slide right in perfectly the first time.

    Now it's just a matter of sourcing appropriate fabric. No weird coatings or treatments, clean edges, and needs to be specifically made to resist punctures and slashes. Not just some fly-by-night crap off eBay. I've found plenty of places that sell various made in China versions of this stuff, but I wouldn't trust that shit in any context, especially inside my body. I'll see what I can find, and then...I might honestly be down to roadtrip over there for some surgery. I'll talk to the local bodymod guy who did my chips first, but yeah. It's on the table. Pun intended.
  • edited February 2015
    Slingshots are for bitches, I'm thinking we test with a good crossbow. :P

    Seriously though, I'll test the bejeezus out of some fabric samples before moving on to the surgery phase. I'll even take video and share it.
  • This looks promising, they have "fabric" as well as "film". I think the fabric is most likely sandwiched with another polymer to keep the weave together, this is how most armor-grade UHMWPE seems to be constructed. The "film" looks like a solid sheet of the material, very thin - probably ideal for this application, no fraying and such to worry about. I'm going to send them some questions.
  • I would go with the film.
    Put it in a pork chop and go to town.
    I would put it in 60% isOH overnight and then in a vacuum for 6 hours. A long list of possible contaminants would be removed this way, including most solvents that may have been trapped during processing.

    Do ti! DOOOOOOOO IT!
  • Yeeeeeeeeeeeeeeeeeeeeesssssssssss! After... Coming up on 2 years of talk, this thread finally yields something we can do! 

    In terms of protection, do you think that one of these implants would alter the effects of a tazer, since you're forcing the current to travel in a different path?

    Do we have any thoughts for first test sites on a human? If it's not too pricey, I might get my hands on some ballistics gelatin, and some of the film, and see what kind of abuse it can take, as well as the reduction in trauma. At the very least, I'll do some research on the material properties(Resistance to strain, etc) and do a bit of math, and come up with some expected results.
  • I could test some of the film against a tazer if I had one, but I do kind of want one anyway, so this may be a good excuse to finally pick one up...I'm not an expert on the tech used, but I think they use small needle electrodes, so it might come down to whether they pierce the plastic armor or not.

    I'm not terribly interested in in vivo testing, given the nature of the implant (if it fails, bad things happen to you), but like Glims said I'll go to town on it with some dead animal meat of various types to see how it performs over muscle, fat, bone, etc.

    Ballistic gelatin is nothing particularly special, you can find the recipe all over the Net. Don't forget the calibration if you want useful results. Also, just to reiterate, this film will do nothing to help mitigate ballistic threats - even a .22LR will zip right through without noticeably slowing down.

    Glims, I don't have a way to vaccuum-ify the film samples.

    Does anybody want to split an order and have some to test on their own while going dutch on the cost of materials? It does get more cost-effective the more pieces one orders. Seems like this might be a good group buy candidate, if enough people are interested in playing with or implanting this stuff.
  • you can get a vacuum inexpensively off of ebay. Also, we have one here.

    If the implant is subdermal i believe the electric charge will probably still get you with a tazer. It doesn't need to get into your muscles, that's more of a as much contact as possible design thing with the needles.
  • So I'm new here so sorry if I say stupid things.

    We accpeted the ballistic subdermal armor as way to difficult to make.

    We arrived at the stab wounds armor. Which is now integrating a film under your skin.

    What if we take another step back and consider the armor against only slashing wounds?

    At first I though putting coated kevlat threads under you skin. You basicaly weave your armor under your skin instead of putting a ready sheet there.
    But putting films as mentioned before would do a better job.

    Then I thought about embroidery with thicker threads.

    I believe there are techniques to do it without the need of cutting your skin, you just pierce it in many points. You can arrange it in artistic patterns/drawings.
    If you need to remove it you just cut in a couple of places and pull the thread.

    The problem is it is transdermal. With tons of points where bad stuff can happen. So is there anyway to make outer part of the thread stick in side the outer part of the skin? I mean not all the way subdermal but like ingrown hair.
    How can we stimolate the mechanism of ingrown hairs?

    Will maiking small cuts  under the thread work?

    Such method is inferior to fabric in terms of amror to a sheet of fabric. But the difference can be easily tested by embroydering a piece of cloth, stabbing it and comparing to the performance of a film. Unfortunately I lack the materials to run such test.

    P.S. I mentioned kevlar because I have seen this article from 30 years ago. Probably other materials suggested in the thread are better.
  • edited February 2015
    It appears you can Embroider on the dead layer of you skin


    No pain, no comlications.

    It will probably fall off after some time (a week?) but you could have a cut resistant skin region and a nice decoration.

    Also it would be nice for the first tests.

    And if the threads pass through dermius?

    I heard microdermal implants cause much less complications then transdermal ones.

    As a stupid idea worth mentioning:
    You can incorporate chain mail into you skin.
  • Ok couple things, 1 micro dermal are the same as a transdermal, just a micro dermal is smaller. Unless they have some sort of special coating, there is still a gap in the skin where bacteria can easily get in.
    2. everything you've mentioned has already been covered in the "it's not a thing and would kill you" area of this thread. You can't just coat kevlar. We now have a biocompatible material, the fabiric that's being disscused that is almost as strong as kevlar. We will be running tests with it and then go from there. It WILL act as a slash and stab resistant covering as that's the whole point of it. Also if all goes well it'll be cross bow resistant as well. If you're interested look into that fabric.
  • So this thread got too quiet. Has anyone continued to look into sourcing material for this?
  • edited April 2015
    @zombiegristle posted a website that supplies the material, but I'm not really sure what kind of specs would be optimal for this project. Here's the link again:

    If we intend to test just the film, they have 3 options:  .075mm thick, .2 mm, and .5 mm. I'll assume that we'd go with .5 for the film by itself. If we sandwhich some of the fabric between 2 layers of film, we've got 5 options. The prices for the fabric range from around $170 for a single 15 x 15 cm sheet to around $900 for 5 50 x 50 cm sheets. Film is cheaper it seems, as you can buy a meter of 610 mm wide, .5 mm thick film for just over $560. 

    Unless someone is willing to fork out $120 just for testing purposes, we're going to need to do a group buy. I can look into other options for sourcing, but it would probably be better for someone with more connections to look into it.

    This site offers the film for considerably cheaper, but the dramatic difference in price makes me wonder what kind of quality we'd be getting. The fabric seems like it's going to be the more expensive of the two, hands down. And it's harder to source to boot. 

    I found something that might be optimal, as it provides the UHMW polyethylene fabric pre-sandwhiched in thermoplastic sheets (Though they don't say what kind of thermoplastic). Here's the link:
  • We'd want the fabric rather than the film. It'll bend better and be more comfortable under the skin
  • Yeah, I'm thinking a group buy would be a good approach to this. I'm happy to help fund testing, but I'm not made of money lol...if I need to pony up for the materials on my own it'll be a couple months at best, I have more pressing expenses at the moment.
  • if people can put together a decent testing methodology and explanation of the risks and benefits. I'll buy you the material so you can test it.
  • Well then you heard the man, lets sort this shit out asap! I have a long line of people who want to be able to take a cross bow to the chest :P So what needs to be done, and in order? My guess is we need to source a cheaper version of the material to imbed in ballistics gel to see how it holds up. We also need to design the exact shape and layering of the materials to make sure it'll take the hit without just folding and wrapping around the thing. Then we need to do a test implant of the material, say an inch square, subdermally to see how the body reacts. If all that goes well, time to get the better quality stuff and get operating on our first test subject. Then we shoot them and see how they hold up. Sp every step of that needs a proper methodology. lets get to work!
  • No? silence? Seriously? Guys come on we get to shoot someone with a fucking cross bow once this is done. I have a subject lined up who would happily let us cover his whole body in this if it works. Let's get this rolling. Don't make me get the motivation brick. 

    here's what needs done:

    -Determine the strength of the material and exactly what weave and thickness we'll want/need. this is a poke through papers kind of thing

    -Determining just how biocompatible this stuff is. see above

    -Sourcing the material yall are resourceful. Find the highest quality at the lowest price. We need to keep costs low so we can get lots of the stuff.

    -Figure out hot to test the stuff. This is straight forward. Probably a bullistics gel test, a small sub dermal test implant then then the full on thing.

  • Shall we start with the material strength testing? Beyond just poking through papers(I'll start looking for info after finals this week), figuring out how the material will behave when exposed to stress whilst implanted should probably be done right off the bat, so we know what sorts of things we should be looking for. For our testing, we should first establish what our target for the degree of protection is. We can either do this after we start testing, and run a full spectrum of tests, and then use subsequent tests to optimize the implant, or decide before and only run tests on protection in the categories we're designing for. In my opinion, the former would probably be better. 
    We should also determine whether our tests are aimed at observing the properties of the materials or the degree of trauma inflicted with/without the material in place.

    For the testing, there are a number of categories we can look at, but I'll just put the reasonable ones in. Each category should have one or more weapons tests in addition to one or more "environmental" tests, unless we can find a way to combine the effects provided by each into a single test. Also, do we want to go to the trouble of designing mechanical systems that can deliver the maximum force found in an everyday environment, or just have a pool of people who perform each test.
    1. Puncture wounds(offending item left in wound) - Weapons:  Stilletto, Ice pick. Environmental:  Sharpened rebar, steel nail, steel screw
    2. Incised wounds - Weapons: Razor, Knives(Serrated and smooth, of a design optimized for slashing attacks), Machete, Katana. Environmental: Glass shard, "sharpened" metal
    3. Penetrating wounds (offending item inflicts wound, and then is withdrawn) - Weapons: Stilletto, Ice pick, Assorted knives(Serrated and smooth). Envionmental:  Same set used for puncture.
    4. Lacerations(Irregular, tearing wounds) - Weapons: Dull serrated implements, Chainsaw (Maybe). Environmental:  Jagged metal.
    5. Abrasions - Weapons:  Not really many "abrasion-based" weapons out there. Environmental: Belt Sander, simulated road-rash( Drop test-sample off of a motorbike/car travelling at fair velocity).
    6. Gunshot wounds - Weapons: .22 Long Rifle (pistol-fired), .410 #8 Shot (shotgun-fired). If it can't stop either of these, there's no point in testing any other round type.
    These wound types cover most of the trauma someone may encounter within reason. I'm not saying we should engineer in a way that optimizes protection in all of these categories, but seeing the material's properties is a must. 
    Leading up to these tests, using the information we gather from whatever papers we look at, and based on some rough estimations and info about the corresponding forces involved in inflicting each wound type, we can select a test-material. That's my two-sense worth for the moment. 
  • In terms of biocompatibility, I know that the material itself is used in various joint replacement implants, but I'm not certain whether or not the material in fabric form is. From the brief read I gave the various papers I'll link, this material in general seems to be very biocompatible, with the only real reactions  being minor inflammation, which occurs years after implantation, as microparticles of polyethylene are ground off the implant and begin to cause trauma. A small side note. As I was doing some research for a paper, I discovered that polyethylene has an effect on the movement of neutrons(Used in hot cell shielding in hospitals). I doubt the thickness we'll be implanting will have any noticable effect, but I figured I'd mention it.

    Here's a paper(behind a paywall) discussing some of its properties from the standpoint of a joint implant:
    This is another one, maybe:

    A basic run-down on the material(Not sure whether it was tested as a fabric, a single-fiber, or a film):

    Another possible source, with some basic specs for UHMW-PE fabric(referred to as fibre):

    Here's a paper about a UHMW-PE/Quartz composite, for use in joint implants(This one's free):

    A slightly less verifiable source, but could yield something:

  • As far as implantation goes, there are a lot of questions that need to be answered, just from a surgical standpoint. Namely, would it be safer and less damaging to implant a few large sized sheets in an area, or numerous smaller sheets? 
    Another very important question is the depth of implantation. Would implanting around the same level that magnets are placed be optimal? Or slightly lower?
  • I'd add to your wound list some lower velocity ammunition, think crossbow and bb/pellet. Lets us scale nicely that way. The rest looks great. 

    Best way to test all these at first is in with ballistics gel. Do a long slab and move the tests down as you go. And have the material sit 2-3mm under the first layer to mimic skin. Ballistics gel is easy to make and most of the tests are easy enough to run. The gun ones are the most expensive by far but we can work something out im sure. Enough of us live in the states. lol

    You're right about the neutron shielding. It's the same material many of the fusion guys i worked with used. I preferred borated paraffin but i digress. Even a thin layer will block out more neutrons than you'd think. The stuff is super dense with hydrogen. My one worry is that it slows them down to make them stop in your body but as long as you don't work around neutrons this won't be an issue. If you do, then really you have bigger problems. 

    I found the fabric on ali express for $23-30 per square meter. So is it damn well priced? yes. Are we sure of the quality? no but that's why we get it so that we can beat the hell out of it with out of body testing and implant a small square to see how the body reacts (or ideally run toxicology tests first but you get the idea). Then if all goes well either use it or get the higher quality stuff for the implant itself. I wouldn't layer the sheets yet. Decide that after the initial tests. I'd be worried that layered sheets would be to easily able to move around. As to multiple sheets, probably a good idea but what would be better is if we could taylor a sheet to be the exact size of the implantee so that it'll fit nicely on them without having to cut it up into bits. Like a well fitted shirt but under your skin.
  • I think you guys are massively underestimating how rapidly injury force scales. These sheets are not going to stop bullets, crossbows, swords, or ice picks. These are things that get thoroughly tested, certified, and sold all over the world in a standardized manner and require a good deal of effort to stop, not just a single sheet of shitty plastic bought from China. Do some reading below, and for the love of everything don't go implanting huge swaths of this stuff in somebody and then attack them to "test it".

    Even well-designed implants are hard to get right (look at all the M31 rejections, despite how awesome those things sound on paper). Don't buy plastic sheeting from China and expect it to be anything useful, biocompatible, or consistent in quality or properties. Implants ought not to be an area where corners are cut, least of all implants meant as a defensive measure.

    Also, it's called "ballistic gelatin", not "ballistics gel". I know it's a meaningless difference, but saying "ballistics gel" just advertises to people familiar with it that you don't know what you're doing.
  • I had a concern as well, how well will the sheets actually integrate, that is, how well will it be anchored? Putting aside zombiegristle's very valid points; say something does penetrate your skin, but not the material. What stops the penetrator from simply dragging the material along with it deeper into the flesh? Strips especially would suggest susceptibility to being dislodged.
  • In a word, nothing. Placing this fabric over soft tissue will be useful against abrasion/laceration, not penetration. Think protecting key arteries and nerves from getting sliced open. To help against piercing injuries it might work over the ribcage, so the muscle wall and ribs provide a rigid support behind the armor similar to studs supporting sheetrock, but it's still not going to be much of a knife-stopper.

    Personally, I would put a small (sub-index card size) patch over my lower ribs on each side in front and in rear, below the pecs to protect the liver and kidneys. I would also put a small strip maybe 1x4" lengthwise down the inside of each upper arm, to act as a shield for the fragile goodies inside there. I might also do 2 or 4 similar small strips in the neck, following the natural contours to try not to booger up my movement any more than I have to. That's it.
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