[HN Gopher] Common food dye found to make skin and muscle tempor...
       ___________________________________________________________________
        
       Common food dye found to make skin and muscle temporarily
       transparent
        
       Author : _Microft
       Score  : 92 points
       Date   : 2024-09-05 19:48 UTC (3 hours ago)
        
 (HTM) web link (www.theguardian.com)
 (TXT) w3m dump (www.theguardian.com)
        
       | _Microft wrote:
       | Paper: ,,Achieving optical transparency in live animals with
       | absorbing molecules",
       | https://www.science.org/doi/10.1126/science.adm6869
        
         | JumpCrisscross wrote:
         | Ah, it "reduce[s] the [refractive index] contrast between water
         | and lipids, leading to optical transparency of live biological
         | tissues." Craziest part being it was predicted using a
         | classical optical model [1]!
         | 
         | [1] https://en.wikipedia.org/wiki/Lorentz_oscillator_model
        
       | arcticbull wrote:
       | From the article, the dye is tartrazine -- FD&C Yellow 5 or E102.
        
         | excalibur wrote:
         | Okay well getting yellow #5 on your skin definitely doesn't
         | make you invisible.
         | 
         | Source: Doritos
        
       | pvaldes wrote:
       | Never tested on humans
       | 
       | Some tropical American frogs evolved to do it naturally (fam
       | Centrolenidae). Some fishes also can do it also in a few
       | different orders (Siluriformes and Perciformes at least), so in
       | lower vertebrates it is possible and evolved several times.
       | 
       | But they have a different metabolism than ours and a mouse skin
       | is much more thin than our own skin. I assume that this effect
       | will work only on very small animals and the optical effect will
       | hit some thickness limit somewhere. Could work on fingers but not
       | in heart. At this moment my hype level is a 4 over 10.
        
         | jldugger wrote:
         | > Never tested on humans
         | 
         | But a few billion have ingested it in the past year, sometimes
         | even in medical pill form to make yellow pills. Could be worse
         | at higher doses but seems plausibly safe and worth further
         | testing.
        
           | karmajunkie wrote:
           | The poison, as they say, is in the dose... just speculating
           | but the quantity of dye ingested versus that used to render
           | skin transparent may be such that the former is relatively
           | innocuous while the latter would be very harmful. In
           | particular it seems to be genotoxic at relatively low levels
           | so that would be concerning for use in humans.
        
       | azinman2 wrote:
       | Truly wild. This could be an amazing advancement if true and
       | safe!
        
         | Reason077 wrote:
         | I imagine it could eventually lead to a full invisibility
         | serum, as documented in the classic Kevin Bacon film _Hollow
         | Man_. Of course, we need to be aware of the side effects
         | (mostly murderous rampaging).
        
           | spuriouserror31 wrote:
           | > Of course, we need to be aware of the side effects (mostly
           | murderous rampaging).
           | 
           | Common side effects include rash, constipation, nausea,
           | diarrhea, dizziness, homicidal urges, drowsiness, insomnia,
           | headache, and dry mouth.
        
       | moralestapia wrote:
       | It says it's never been tested on humans and the proper diligence
       | should follow,
       | 
       | But given that we already eat large amounts of it with no harmful
       | side effects, the expectations are good.
        
         | ryanwhitney wrote:
         | eh i just put some on the top of my hand and i didn't see any
         | bones
        
           | DFHippie wrote:
           | Maybe you should get that hand x-rayed. Is it particularly
           | bendy?
        
           | pfdietz wrote:
           | Tim: _Look at the bones!_
        
         | gus_massa wrote:
         | The dose makes the poison. Considering that food usually don't
         | make your tongue transparent [1], probably you need to use more
         | than the usual amount to get the effect.
         | 
         | [1] Note that they get skin that is transparent only to one
         | shade of red, it's not transparent to all the visible spectrum.
        
           | moralestapia wrote:
           | The _absorbed_ dose makes the poison.
           | 
           | The effect of a substance is usually three orders of
           | magnitude lower when you rub it on your skin vs. when you
           | swallow it.
        
             | JumpCrisscross wrote:
             | > _effect of a substance is usually three orders of
             | magnitude lower when you rub it on your skin vs. when you
             | swallow it_
             | 
             | Going out on a limb and guessing you're at an effective
             | dose for _something_ when it 's making your skin
             | transparent.
        
       | alwa wrote:
       | I'm surprised that this characteristic of an extremely common dye
       | --being used in its main application, as a dye--hasn't been
       | described before. Surely there's some limitation that's obvious
       | to those skilled in the chemical and biological arts?
       | 
       | Or is it really just a matter of serendipity waiting til now to
       | lead anybody down the path of trying it this way?
        
         | RobotToaster wrote:
         | Given how common it is, it does seem weird that nobody has
         | spilled it on themselves and noticed this effect.
        
           | rincebrain wrote:
           | The article says it's only to the depth it penetrates, so
           | given that you have a lot of skin, comparatively, I'd guess
           | it'd be hard to distinguish from the dye staining you weirdly
           | for a bit.
        
           | ckemere wrote:
           | Makes me want to rub on some Doritos just to see...
        
       | sschueller wrote:
       | > while smearing it on the rodent's scalp allowed scientists to
       | see blood vessels in the animal's brain.
       | 
       | Since when do mice not have skulls?
        
         | griffzhowl wrote:
         | My thought too but later in the article it says that was by
         | using the dye in combination with laser speckle imaging
         | (whatever that is)
        
         | dylan604 wrote:
         | Everyone knows skulls are transparent in everything except
         | x-rays. It is known
        
           | janalsncm wrote:
           | Skulls aren't transparent in visible light either.
        
         | mattkrause wrote:
         | Mouse skulls are very thin and you can sometimes image directly
         | through them!
        
       | ardrak wrote:
       | > At the moment, transparency is limited to the depth the dye
       | penetrates, but Hong said microneedle patches or injections could
       | deliver the dye more deeply.
       | 
       | Reverse tattoos incoming.
        
         | RobotToaster wrote:
         | If it dissolves in DMSO, penetration should be vastly improved.
        
         | FjordWarden wrote:
         | Sorry for being nerd, but your internal organs are going to get
         | UV damage.
        
           | murphyslab wrote:
           | UV damage to internal tissues seems unlikely given that the
           | tartrazine dye they used absorbs strongly in the UV region of
           | the spectrum. You can see this in Figure S1 A & B:
           | 
           | https://www.science.org/doi/suppl/10.1126/science.adm6869/su.
           | ..
           | 
           | Also the abstract of the article notes that strong UV
           | absorption is likely a prerequisite for this effect:
           | 
           | > We hypothesized that strongly absorbing molecules can
           | achieve optical transparency in live biological tissues. By
           | applying the Lorentz oscillator model for the dielectric
           | properties of tissue components and absorbing molecules, we
           | predicted that dye molecules with sharp absorption resonances
           | in the near-ultraviolet spectrum (300 to 400 nm) and blue
           | region of the visible spectrum (400 to 500 nm) are effective
           | in raising the real part of the refractive index of the
           | aqueous medium at longer wavelengths when dissolved in water,
           | which is in agreement with the Kramers-Kronig relations. As a
           | result, water-soluble dyes can effectively reduce the RI
           | contrast between water and lipids, leading to optical
           | transparency of live biological tissues.
           | 
           | https://www.science.org/doi/10.1126/science.adm6869
           | 
           | However this kind of research into the effects of absorption
           | bands on the transmission properties at interfaces might
           | ultimately bring about more effective sunscreen formulations.
        
       | freen wrote:
       | Awesomest Halloween ever.
        
         | amelius wrote:
         | "I can tell what you had for dinner"
        
       | moribvndvs wrote:
       | In Doritos? How are call of duty players not constantly
       | transparent?
        
         | ThrowawayTestr wrote:
         | Their skin is transparent but cheeto dust isn't
        
       | teeray wrote:
       | I've seen this movie. It doesn't end well for Kevin Bacon.
        
       | swayvil wrote:
       | Halloween costume!
        
       | seydor wrote:
       | introspective people eat doritos
        
       | aster0id wrote:
       | New kink incoming
        
       | evan_ wrote:
       | When my little brother was 3 or 4 he stepped on a nail in our
       | yard, probably dropped during some recent construction. It went
       | all the way through his poor little foot, straight through, out
       | the top. I can see it, vividly, in my mind's eye. Mom scooped us
       | up and rushed us, still barefoot, to the ER. I remember him being
       | almost calm- not the way I would have reacted. They x-rayed his
       | foot and soaked it in a tub of what I now know to be iodine to
       | kill bacteria. I remember this clearly: it was the first time I'd
       | ever seen an x-ray in real life, rather than just in alphabet
       | books.
       | 
       | Fortunately the nail totally missed anything important, so they
       | just pulled it out and bandaged him up- no worse for the wear. He
       | went on to be an honest-to-God track star so it obviously didn't
       | have any lasting effect.
       | 
       | Decades later we were talking about something and he said to me,
       | "Why don't they use that x-ray water anymore?". I had no idea
       | what he was talking about so I asked him to elaborate.
       | 
       | The way _he_ remembers the incident is that they put his foot
       | into a bucket of amber liquid and, once submerged, his skin
       | became transparent. He looked in and saw his own bones, blood
       | vessels, and- in the middle of it all- the nail that was causing
       | such a fuss. He described wiggling his toes, flexing his ankle,
       | and seeing the bones and tendons move, directly, with his own
       | eyes.
       | 
       | His toddler brain, probably in shock, had combined the x-ray film
       | and iodine bath. Over the years it had grown more detailed and
       | reinforced. He described it with such clarity that I almost
       | wondered if I hadn't been mistaken. He didn't believe me when I
       | told him how I remember it. We called our mom who confirmed my
       | version of events, plus did some googling, which finally
       | convinced him.
       | 
       | Anyway I just sent him this article. It's interesting that not
       | only is the x-ray water he remembers theoretically possible, it
       | would actually be amber.
        
         | knodi123 wrote:
         | That's fascinating! I also have a vivid childhood memory that I
         | can see, clear as day, despite knowing as an adult that it's
         | impossible. It's really uncomfortable to combine the facts that
         | a.) memory is unreliable, and b.) memory is what gives me my
         | sense of self.
         | 
         | (if you don't accept that second fact, that's fine, I'm not
         | here to convince anyone or debate)
        
       | adamredwoods wrote:
       | I wonder if this would improve Digital Optical Spectroscopy for
       | cancer detection and monitoring?
       | 
       | Also related: https://www.ycombinator.com/companies/eden-2
        
       ___________________________________________________________________
       (page generated 2024-09-05 23:00 UTC)