# Specific uses for synthetic skin [closed]

I need a reality check on a character with synthetic skin. I have some cultural back story to explain it, but I also have several plot points where it comes in handy.

Background: Synthetic skin is a nano-virus that is injected into a person's skin with a needle like a tattoo. On planets with harsh environments it is utilitarian, typically used to protect exposed skin from chemical or temperature burns, exposure to cancerogens, repetitive bruising, etc. It has developed cultural significance and is sometimes an artform and a badge of pride, but it is rooted in planet colonization. It also indicates you aren't from one of the ruling planets, so while larger tattoos might lend street credibility it also makes one conspicuously working class. Synth skin replaces the existing skin cells and becomes a part of the skin, sharing nerves, capillaries, etc.

My character has a full-body synth skin. All her skin has been replaced, started as a child by her mother who intended to sell her. It is mostly aesthetic (exotic sci-fi painted lady) but I need it to have a few specific handwaveum properties I'd like to get your input about.

1. It can be reconfigured by an artist using some kind of nano-manipulator brush, so colors, designs, patterns can be altered with a trip to the beauty spa (it never looks like "natural" skin).
2. The synth skin can filter nitrogen bubbles from her blood, giving her an advantage when diving or changing atmospheres.
3. She can withstand sulfuric acid vapor in the atmosphere (like the cloud deck of Venus) with only a gas mask (small emergency oxygen mask?), long enough to perform a physical activity outside that would kill (or severely burn) everyone else.
4. She can't get drunk or high, at least not for very long before the skin filters it from her blood.
5. Synth skin cells eventually "die" and must be replaced with new seed injections of the nano-virus into deeper skin. Most of her synth skin however is damaged in one incident, exposure to cold, and is replaced with new and improved™ synth skin. She spends about 9 months in medical suspended animation while it regrows.
6. She improbably survives (<1 minute) inside an electro-plasma magnetic foundry fusion doohickey thanks to the Leidenfrost effect or a plasma double-layer or maybe an electrostatic sheath.

Thank you for any feedback.

## closed as unclear what you're asking by Mołot, Alexander von Wernherr, L.Dutch♦, Snow, Youstay IgoFeb 20 '17 at 12:40

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• I don't really see a question here. You state a lot of properties that you want to handwave. If you handwave your nano-virus-synth-skin you can do whatever you want to do. Do you need a reality-check whether e.g. changing all of the skin of a human to a more capable one would give someone an advantage when diving? Or do you want a reality-check about the plausibility of changing all of the skin? Or do you need a reality-check on any material/virus/... that would help achieve your six goals (which is quite a lot for this format)? – Secespitus Feb 19 '17 at 21:52
• I might consider deleting this and asking it as some separate questions along the lines of, "how can I scientificishly handwave property x of my skin" – Dubber Rucky Feb 19 '17 at 22:17
• Reality check makes little sense when you say it's handwavium. – Mołot Feb 20 '17 at 6:30

To recap: you want a minimum-handwaving solution to this list of synthskin properties. Much will depend on how much you're prepared to pay, in storyline terms; these properties will have causes, and consequences.

• It can be reconfigured by an artist using some kind of nano-manipulator brush

This is the easiest part. The newly gengineered skin cells may have chromatophoric properties, possibly as part of their other functions. I.e. you're looking at a differentiated cell layer with different cells optimized for different properties. When the "acid resistant" cells emerge from the inner lattice and expand to seal the upper layers, the skin color and texture becomes that of the acid-resistant scales.

• The synth skin can filter nitrogen bubbles from her blood, giving her an advantage when diving or changing atmospheres.

Also "easy", even if this will have a high metabolic cost, in that we know how this might work. Also you can't just alter the skin, this requires modifying capillaries too, to achieve sufficient blood flow. Your "skin" will need specialized cells containing nitrogenase enzymes, and convert molecular nitrogen to ammonia and then to uric acid; then you have the problem of getting rid of the uric acid. If you're doing this in a marine environment, it would be easy to get rid of ammonia through an osmotic membrane open to the seawater. The main problem is that ordinary nitrogenases aren't fast enough - you'll need both a rete mirabile-like layer below the dermis to supply reaction surface area, and a nitrogenase family of enzymes based on unobtainium instead of commonplace iron, vanadium or molybdenum.

• She can withstand sulfuric acid vapor in the atmosphere (like the cloud deck of Venus) with only a gas mask (small emergency oxygen mask?), long enough to perform a physical activity outside that would kill (or severely burn) everyone else.

Heh. This requires the skin to not rect with sulfuric acid, which requires it to have a sealable layer of very unreactive substances; unreactive substances (and here you're looking at nothing less than tetrafluoroethylene) are a copper-plated bitch to synthesize, and you need a completely different biochemistry to handle them. Or you don't use a virus and go the full nanonic assembler way. Possibly the virus can construct an organic Waldo factory that assembles inorganic nanobots, and all the necessary machinery to produce PTFE-plated cells.

Another, less tasteful possibility is the secretion of a protective oily mucus. This can be done within the limits Earth biochemistry, but its resistance to sulfuric acid is not absolute. The slime of course must not be water-based. It would also explain why she only can do this for "short" periods however.

• She can't get drunk or high, at least not for very long before the skin filters it from her blood.

This could be a byproduct of the nitrogenase filters in the blood. They will also work against carbon mono- and dioxide, and against alcohols. Can't have them doing too much though, or it will interfere with the respiratory reflex.

• Synth skin cells eventually "die" and must be replaced with new seed injections of the nano-virus into deeper skin. Most of her synth skin however is damaged in one incident, exposure to cold, and is replaced with new and improved™ synth skin. She spends about 9 months in medical suspended animation while it regrows.

Well, this could explain the acid-resistant coating - it's not biologically produced at all, must be supplied ready-made from the outside. Regrowth would never last nine months however; in that time, the skin has time to die again by itself.

• She improbably survives (<1 minute) inside an electro-plasma magnetic foundry fusion doohickey thanks to the Leidenfrost effect or a plasma double-layer or maybe an electrostatic sheath.

This last is less unlikely than it seems: electromagnetics don't work on biological creatures unless you set the power setting to 11, and plasma sintering could be easily counteracted by the same insulating layer that gives acid resistance. Death for a normal human would be mainly provoked by a mixture of vacuum exposure and electrocution.

You cannot very well use the Leidenfrost effect because you'd need an ablative layer which wouldn't last more than a few seconds, and not in a vacuum anyway (and you can't have plasma effects in any reasonable atmosphere, unless you employ really high power levels - "lightning strike" or "nuclear detonation" levels). Electrostatic sheath is marginally possible but it would require a sizeable organic capacitor or other power source, which can't be supplied with synth skin. Unless your girl is going full cyborg; also, any technological power source would contain conductive metals or even ferrous metals, and would require a significant shielding to be able to work inside a plasma chamber.

I think that passive insulation (and a not too unreasonable chamber power) is the best you can reasonably expect to be aiming for.

UPDATE: if by "electro-plasma magnetic foundry fusion" you are referring to a Tokamak-style hot hydrogen fusion reactor, then NO. WAY. Sorry. Not with synth-skin, not with anything else. No ordinary matter can survive there. You would need a magnetic shielding strong enough to disrupt the fusion bottle, and this would result in a massive explosion or, more likely, in the whole reactor being SCRAMmed in as few milliseconds as inhumanly possible by the best security systems money can buy. A disrupted magnetic bottle with multimillion-degree plasma going amok is definitely something you don't want when you design a reactor. Also, such a reactor would be impossible to power up with someone inside, to boot.

• Thank you for very thorough suggestions! I will go through you links and make adjustments to my ideas. – wetcircuit Feb 19 '17 at 23:39
• I especially like the Teflon coating! – wetcircuit Feb 19 '17 at 23:49

Your 'synth skin isn't for ruling class' sounds a lot like past pale skinned nobility. Though if the robotics in your setting are very advanced, humans might never be required to do any physical labour in hazardous environments anyways.

As for your points, my ideas per point:

1. It should at least be able to mimic the colour of normal skin. It could be that the shean is unnatural, or maybe it just looks too smooth (like someone wearing too much make-up). Other than that, I recon changing the pigmentation of something that's possibly designed to undergo colour changes shouldn't be a problem, it could be like dyeing your hair, and maybe the colour fades after too much exposure to UV/harmful substances.

2. Skin usually only has very thin blood vessels flowing through it, I don't know how large nitrogen bubbles in your blood are after a pressure drop, but one problem might be that they're too big to get near your skin.

3. There's plenty of acid-resistant plastics out there, so this is plausible.

4. Filtering out alcohol or similar substances would take a lot of energy, but it should be possible (your liver's already doing it).

5. Injection into deeper skin sounds like at one point, you're gonna run out of layers of skin. Hasn't medical tech advanced enough that you can properly regrow skin?

6. You might survive a few milliseconds in a fusion reactor plasma. Fusion reactors reach millions of degrees, and there's nothing we could likely invent that can withstand those temperatures. So your best hope is that the synth skin has a low thermal conductance and a high heat capacity. That way not all of it ablates and it doesn't transfer heat to your deeper skin layers. This already assumes none of the plasma actually hits you, just the thermal (and visible, UV, X-ray and gamma) radiation. The heat flux from current fusion experiments is about $600 MW/m^2$, or about what is needed for 2nd degree burns in a millisecond. Not to mention the ionizing radiation.

• All very helpful, thank you. I will do more research for #2, and consider how to scale back #6. – wetcircuit Feb 19 '17 at 23:30