Subdermal Armor



  • edited June 2016
    I'm a long time lurker only started posting recently but I'd think that sheer-thickening materials would at least be worth examination, specifically materials based on fibroin, it's biocompatible and there is already a lot of research around building materials with it.

    It might not be suitable for stopping bullets (depending on the lag between application of the shear stress and the change in properties) but a soft spongy armour that goes rigid and spreads impact over a larger surface area could mean the difference between a cracked rib and punctured lung.
    Also it could allow blood vessels to grow right through it so no problems.

    Even if not suitable as armour it could be used to support plate armour or mesh.

    I think a bigger concern for any armour solution would be how to stop it from migrating around the body.

  • @Dr_Allcome
    Are you talking about self healing alloys? I alway thought those were internet hoaxes....
  • @JohnDoe, nup not self healing alloys... just extending the discussion on non-newtonian fluids... basically adding my 2 cents that looking for a bio compatible "armour gel" (shear-thickening fluid) would be a good place to start.

    Here is a link to video about polish researchers who have one they say is better than kevlar [LINK]

    But what I was thinking was that most of these fluids are mixtures of particles and a fluid medium (e.g. cornstarch and water) - if implanted (between the abdominal wall?) the body would provide the fluid component and small blood vessels could actually grow through the gel so tissue should remain healthy.

    I would think that materials to consider would be silk, collagen, and fibrinogen, if silk fibres could be impregnated with proteins allowing them to act like cornstarch in solution, then we'd have an armour that could be implanted with nothing more than an injects and (mostly) removed the same way (if slowly).

    It could even be topped up if needed.

    It's just an idea that came to me when I was reading the thread... 

  • So, if you were gonna implant something like this, it'd need to contained in a bullet resistant, biosafe pouch of sorts. Something like UHMWPE would do nicely here. For your non newtonian fluid you'll want silica nanospheres suspended in a nice inert silicone oil. This will not work if the bits are free floating in the body. There's no toping up. 

    As to self healing materials. no they aren't science ficition. Most are plastics that are full of microcapsules full of solvent so when the part breaks the solvent is released, allowing the nearby plastic to melt and reform. The other way it's done is by putting an easy to open ring molecule like furan so when the plastic rips you can place it backtogether and expose it to uv. It'll cause the ring to open and cross link whatever's near it. This is normally done with a mixture of epoxy/ furan and chitosan. Then there are alloys like nitinol which are shape memory alloys so when you heat them up they go back to the the shape they're supposed to be. 
  • @dr_allcome
    Okay I have never seen one that could stop a bullet, sound vary promising though.
  • edited June 2016
    Would we still need the bag if the STM was not a mixture of silica and oil but rather a mixture of biosafe particles and extracellular fluid? if the particles stimulated the generation of the fluid by the body (like a very mild version of the effect of polypropylene)?

    I'm thinking implants like this could useful not just as armour but also cosmetics and possible even for the elderly to get in order to provide protection/support for fragile hips  as part of hip replacement op.

    @JohnDoe the video I linked to above stops bullets, was not thinking of anything that hard for internal use tho.
  • Yes. what you're suggesting wont work. The body is already full of proetins and stuff. if you don't contain the sheer thickening fluid it'll be too spread out to do anything useful. Also, this wont help the elderly. Their bones break because they're brittle and their musculature is atrophying. No amount of armour will stop that. That's a stem cell/genetics project, not an armour one. I think your best bet for true subdermal armour is thin pouches full of STF and a 5-8 layers of boron carbon fabric or UHMWPE. If you use UHMWPE it'll be biocompatible. Also use a biocompatible silicon oil of which there are a few and particles that can be removed by the body. I dunno how silica will play, so you could switch it out for something else if you really wanted. You could make the whole thing about 3-4mm thick tops and implant it without it being too noticeable. The addition of STF to 4 layers of kevlar (or UHMWPE or w.e else you use) can cut the amount of layers you need usually in half or better. 
  • edited June 2016
    The body is corrosive so it stands to reason that a self healing alloy like what you discribed could be made to function in the body right? Granted it's pointless this is something you would be to get you out of only one situation then replaced ASAP.... I don't want to get on to the one shot one go train, cause I think it has been brought up before.
  • as a rule, self healing plastics and the body do not play nice together. And it'll be a long while till there are biosafe/cheap versions
  • What about the one shot one go part?
  • edited June 2016
    That's most armor nowadays. Besides, subdermal armor vs. a bullet will leave lead residue, which you don't want inside you.

    @Chironex Do you have any idea how bio-compatible Graphene-laced polyethylene would be?
  • I've made some and it's pretty good stuff but it's still needs to be way too thick and it's far too rigid to be useful. Im gonna use something like it to make new bullet resistant armour (not subdermal) once I get set up in a new lab after chile... eventually. 
  • Coming back to this, it seems like the best workable solution would be a combination of UHMWPE panels/strips and a titanium mesh seeded with a hydrogel-HA composite, to eventually grow a bone lattice around particularly vulnerable areas, like the femoral artery.  Once ossification completed, it'd provide the framework necessary to keep the UHMWPE from simply being pushed into the wound, as was mentioned earlier.
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