Exactly what it says on the tin: how would one go about making a subdermal (i.e. under the skin) Faraday cage?

Specifically, are there any physical or biological principles that could be applied to do such a thing, while doing so in a fashion that is consistent with known biology and physics?

Preferably, this could be something that an infant could be genetically modified with and that they could "grow into", but I'm willing to take all comers.

Inspiration here.

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    $\begingroup$ @ErdelvonMises I'm not doing that until this has been up for a few days, in case a better one comes along. I'm not saying yours is bad, but there might be one that somehow answers my question more accurately. $\endgroup$
    Oct 31, 2021 at 12:00
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    $\begingroup$ @ErdelvonMises, don't be pushy. Answers are not to be accepted based on who most asks for it $\endgroup$
    – L.Dutch
    Oct 31, 2021 at 15:38
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    $\begingroup$ @ErdelvonMises OP can wait as long as they want before accepting an answer, until they are satisfied with something that solves their problem $\endgroup$
    – L.Dutch
    Oct 31, 2021 at 18:11
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    $\begingroup$ @ErdelvonMises I mean, you asked me to, so you're kind of splitting hairs here. I'm not interested in continuing this train of discussion. $\endgroup$
    Oct 31, 2021 at 18:16
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    $\begingroup$ @ErdelvonMises Yes. $\endgroup$
    – fectin
    Nov 1, 2021 at 11:49

6 Answers 6


Frame shift: subepithelial (superdermal) Faraday cage

This is an answer to a slightly different question: Putting the conductive layer under the dermis is hard, because the bottom edge of the dermis is irregular and intertwined with the hypodermis. It could be placed more deeply (superficial fascia, etc), but I'd rather look to the boundary of the two major layers of the skin: the basement membrane. Putting the cage above the dermal layer means that it defeats miniature spying devices with which the victim might have been tattooed via weapons shot at protests (I've seen a paper proposing these about 20 years ago, ought to look for it...) or injected/vaccinated etc., which could hide in the dermis itself.

The basement membrane provides a fairly continuous barrier around the body. We just need to make it electric. For this I'll suggest beta-carotene as raw material. This is pretty much what biology uses for wire - in plants, it collects light for photosynthesis, and in humans, related compounds (vitamin A and more specifically 11-cis-retinal) are used to detect light. If we eat it in large excess, the skin will take on an orange color. We're going to change that color so it absorbs a wider range of (lower) frequencies.

beta carotene with 11 conjugated double bonds

The trick of this molecule is in the double bonds (=) which can be shifted to either side and still connect all the atoms correctly, if charge is introduced to one end and the other end. All we need to do to make it more graphite-like (conductive) is to extend this network by an enzymatic reaction that links these structures together with another bond. We need to evolve a new enzyme from scratch, most likely, which is a task of some difficulty but definitely doable, especially since there are many known domains that bind to and react with vitamin A derivatives. I only took the briefest look at PubMed to scan for something already in existence, and there's a chance if you dig into KEGG or other compilations of biochemical pathways you can find something useful already from nature.

When making such an enzyme, we should tweak it during development so that:

  • It has a relatively poor binding affinity to beta-carotene. We don't want it stealing retinoic acid needed during development or vitamin A the baby needs for night vision - only when beta-carotene is consumed in excess will an appreciable amount bind and react.
  • The reaction has some reversibility. We're not going to spend a fortune in energy to make this happen, and we don't mind if the network can spontaneously be broken down when beta-carotene concentrations are low. This will cause the network to double as a vitamin storage for the infant and ensure it is possible to give up the cage with a prolonged period of sticking to the Recommended Daily Allowance, if there is a medical imaging issue. But vitamins with megadoses of beta carotene have been very easily available; and if that fails, there are carrots (yikes!), so this is not a large bother.
  • The enzymes for the reaction need to include binding sites that attach somewhere on proteins of the basement membrane, for obvious reasons. Otherwise we're laying these down in random places. They should be secreted by basal epithelial cells, I suppose. Their production should be very strongly repressed in any tissue of the eye, and their activity should be allosterically inhibited by ceramide or other compounds common in the retina. More safety considerations would be needed ... we don't want any foul ups!

[Apology for a minor jest: the proper term is supradermal, but "Superdermis" sounded more heroic]

  • $\begingroup$ Thank you for a scientific answer and a relevant frame shift. +1 $\endgroup$
    Oct 31, 2021 at 15:32

Tattoos made with conductive ink have been proposed. All the examples I've seen so far have been surface ink. I'm not sure if that's for reasons of toxicity or because people don't seriously want to have permanent circuitboards inscribed in the skin. But the surface ones are conductive enough to attach lights and power sources.

See Silver Nanowire Inks for Direct-Write Electronic Tattoo Applications

  • $\begingroup$ ...did you make an account just to answer this question? $\endgroup$
    Oct 31, 2021 at 12:37
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    $\begingroup$ No, I didn't make an account at all. I have philosophical/moral objections to any form of Argument from Authority, so I don't like to participate in any system using 'reputation' scores. But I do enjoy answering questions, and being helpful. $\endgroup$ Oct 31, 2021 at 12:46
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    $\begingroup$ We would be wiser by far to consider all 'authorities' and 'experts' like they were random internet strangers, and judge each answer on its own merits. I try not to make a big deal of it. Each to their own. $\endgroup$ Oct 31, 2021 at 12:55
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    $\begingroup$ @wizzwizz4 Absolutely true, if the expert is saying something completely off the wall, then it invalidates his position of authority. What I'm saying is that, all else being equal, experts should absolutely have more credibility than random passersby from a starting position. Credibility is like trust - it must be earned and it can be lost. $\endgroup$
    – Abion47
    Nov 2, 2021 at 15:00
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    $\begingroup$ @wizzwizz4 The layperson wouldn't benefit from a mathematician handing them a proof, as depending on its complexity they would likely be unable to read it much less verify it. This is why the appeal to authority, while fallacious, is oftentimes unavoidable when dealing with the general public because, at the end of the day, people have neither the time nor the level of understanding to properly vet an expert's claim. But in the long run, we already have a system for this - peer review. Expert claims can be debunked by other experts, and if enough of them speak up, the debunking will stick. $\endgroup$
    – Abion47
    Nov 2, 2021 at 15:23

It would be difficult to get a biological process that'd create a metalic mesh, becuase the thing DNA is good at making, protein, and similar biology-ish chemicals is the thing metal isn't.

However, all is not lost! It doesn't necessarily have to be metal! There are conductive proteins, and it might be feasible that a correctly designed mesh would have similar properties to a faraday cage.

Heres at least one suggestion;- https://pubmed.ncbi.nlm.nih.gov/27409066/

I'm not too sure the physics of this, and I'm not sure an internal faraday cage is going to be particularly useful, since the goal is to keep that EM energy away from the body, rather than ground it inside of the body. That might require a physicist to chime in on this. I might add, that grounding is important, the EM captured and diverted by the cage has to go somewhere. Newton does not negotiate with terrorists and sci-fi authors, conservation laws are a constant in any concievable universe worth concocting.. So you'd have to work that problem out too.

If you put it on the surface though, you could have your character displaying a nice metalic sheen, since one property of conductivity is reflectivity.

  • $\begingroup$ Is this sufficient? From the image on the wiley page they have a conductivity of 977 S/cm, compared to copper of 58.14 x 10^6 S/m. $\endgroup$
    – Dave
    Oct 31, 2021 at 11:38
  • $\begingroup$ @Dave satisfactory. Microwave won't penetrate more than 1-2cm into your body. It may boil your skin, but rest assured your heart will continue beating in the process. $\endgroup$ Oct 31, 2021 at 11:54

Blood vessels are a wonderful criss-crossing madness on their own. I'm not entirely certain how feasible or survivable this is, but since there is iron in our blood and copper in the blood of molluscs I'd imagine it wouldn't be too big of a stretch, even if nothing in nature currently has this, for the body to use iron/copper atoms in the construction of a person's veins at a relatively high amount/concentration.

This may lead to something like the veins themselves being slightly metallic with all the good and the bad that comes from that. Who/whatever has these veins would be rather conductive throughout their whole body and will have a bit of a bad time at airports and all sorts of situations that involve metal detectors.

  • $\begingroup$ There is iron in our blood in the same sense that there is chlorine in table salt. You can rub salt into wounds, and even eat it, but a tiny bit of chlorine gas and your skin will start burning. I'm not saying iron is not survivable, but further research is needed; I think you'd have to have a maintenance process to stop the metal being reacted away, at the very least. $\endgroup$
    – wizzwizz4
    Nov 2, 2021 at 12:10

Bad news: to protect against high voltages, you need a very low resistance, probably only to be found in metals.

So unless you go the way of some semi-plausible body-temperature organic superconductor, which you could, the only alternative is a metallic mesh, probably gold, or copper or silver sheathed with something biocompatible and non reactive.

The advantage with gold is that beside having very low resistance, you can have really tiny wires, that do not interfere with the organism and need little sheathing.

To thread the wires throughout the skin, you'll need either specialized mites (genetically engineered Demodex for example, except they'd need to burrow - so, something more like D. Medinensis) or nanomachines, and a gold-based skin lotion to supply them with the raw materials. The lotion could contain millions of really tiny carabiners, and the mites would assemble them in chains and thread them throughout the organism.

Or the mites could assemble the carabiners themselves out of ordinary materials, building exotic compounds such as bond-strained thiafulvalene-catenane (fulvalene was one of the first groups used in high temperature superconduction back in the '80s, and catenanes are a novel class of pseudopolymers that possess literally infinite flexibility. Best of all, they could be built from ordinary organic CHNOPS if one had the appropriate molecular machinery. The only hand-waving here is the hypothesis that bond-straining certain groups could "gift" them with superconductivity, as it seems to happen with thiocarbo-pseudohydride).


If your idea is protect the whole body from microwaves you are out of luck. No way to metallize a human body skin is scientifically plausible. But human body skin and muscles are rich in salt and salt is conductive. Maybe if you connect such tissues to earth you cold make a reasonable Faraday Cage. But attention!!! It can work to block low energy electromagnetic waves. It will not protect from strong microwave action. As Adrian Colomitchi has commented it is not a good idea, and, connect skin and muscles to earth cam make you much more in risk of ordinary electric shock.

But if your idea is people were born with a natural "Tin foil hat" you could be more lucky.

You need to metallize only the skull. I think, maybe, because human skull is mostly made of mineral (calcium) matter some none could mess up with DNA to make the human skull bone metallized with iron, maybe cooper.


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