On a trans-dermal power source

I really think a trans-dermal power source is viable.  It would require a bone anchor and extensive surgery though.  

Perhaps even replacing a small bone with an artificial one that incorporates both battery and charger. The issue of the skin pulling back has already been solved.  http://imgur.com/DgRMuV0 
I'm not sure where I got that image from, it was a article on trans-dermal prosthetics in dogs.

It would simply require transplanting of cultivating more of the perlosteum prior to implantation, to cover all of the that would remain inside. To help protect against infection, the portion of the implant that sticks out would need to be patterned with Sharklet, or some similar substance.  
The skin around the implant that would be held to the perlosteum would also need to be reinforced to be more durable somehow. 

Another issue I have seen people raise here is the issue of power cables.  Yes, the higher amperage cables require very tight connections, which might be painful when being pressed down upon.  But it should be relatively easy to create a cable that is held on with a small magnet instead of tension, and just holds the transfer surfaces together that way.  One of the contact surfaces would just need to extend slightly further than the other, to insure they didn't get hooked up backwards.

The power coupling would need a water/dust proof cover, which will make the exterior slightly bulkier. All of the newer Olympus cameras have small, light-weight covers over their battery compartments, and a similar design would work admirably.  

As to where such a thing would go, I think it would best work as a replacement for a clavicle. There is plenty of (relatively) empty space surrounding the clavicle, so that the dimensions of the implant could be varied a bit to fit functionality.  I have zero experience with CAD or any other design program, so I'm not sure how much movement range you could lose by changing the shape of the implant, though.


  • Setting aside the discussion of keeping a transdermal implant clean, the issue of a magnetically attached power source has already been addressed by Apple with their Mag-Safe connector.  No need to reinvent the wheel there.  If I were to have transdermal power implanted in my body though.  I would also want it to also include a data connection, like USB, which I think would be an excellent candidate for transdermal use with the micro format connector providing both small size and low insertion force.

    I'll let others explain why transdermal might not be the best way to go though.

  • I've been thinking about transdermal electronics recently, and wondered about the viability of a short cable with the connector at the end? I'm imagining something like a 2-3" micro-USB for charging small implanted electronics. This would remove any risks associated with insertion force, and you could tape the cable or even have a magnet to retain it against the skin when not in use. Would coating a cable or socket in Parylene or another anti-migration coating help at all with sealing a transdermal site?

    (sorry for the slight thread necro, I felt this was better than jsut starting a new topic for my silly questions)
  • edited July 2013
    i see no reason why you would want a transdermal just for power and data. both can be delivered without the need of transdermals, avoiding all problems transdermals usualy drag along.
    transdermals would have other interesting applications. especially for bio-mechanical constructions.
  • @ThomasEgi, I a gree that subdermal power and data coupling would be ideal, but presently, the only technology mature enough is NFC and that severely limits the amount of transmitted poer and transferred data to short packets. This might bee OK if the implanted circuitry had more memory and processing power than is currently available.

    However, since we are living now instead of in the future, I like the idea of discussing transdermal as an interim solution while better subdermal solutions are being developed. Transdermal power has the advantage of greater capacity without the hazards of subdermal battery implants.  The downside of transdermal implants, i.e. the risk of infection and rejection at the site where the connector emerges and the personal hygeine required to prevent this, are well known.  I am not willing to reject transdermal out of jand just because it has higher maintenance requirements than subdermal.

    That said, I still think subdermal should be our long-term goal and that transdermal should be used sparingly.

    My main motivation for wanting a transdermal micro USB connection is so that I can take advantage of currently available technology to emplant things like flash memory, accelerometers, and other devies that are currently available as wearable tech.

  • transmitting power is not exactly rocket science. even plain old 128kHz (which is easy enough to diy from discrete parts) can get you 2-digit milliwattage. not a lot, but for most implants that'll be more than enough.

    same goes for data. it all depends on how fast you need to go. if you just want to cross the skin, a red-led based optical transmitter will easily get through some mm of skin and get you , i'd say 32kbps without much trouble. rfid for data works aswell.
    separating those 2, data and power, gives a lot of flexibility.
  • Hi everyone,

    I've been lurking here but this is my first post. I wanted to run an idea past people on this issue. I am far from an expert on this, I'm just curious.

    As many have been, I was trying to think up some ways to connect power and data to an implant and obviously transdermal isn't the ideal solution for all the reasons above. What are your thoughts on...

    Spikes. Haha. Having a connector on the implant that is raised enough to reduce travel distance then a 'plug' with thin enough spikes to puncture the skin. Not ideal and obviously with many obvious disadvantages but would once a contact was made, would it be possible to transfer data/power?

    My other thought was on Microdermal piercings. They use an anchor that sits in the skin and then allow jewelry (normally) to screw in. Has the (aesthetic) effect of transdermal but apparently without the complications. Would it be possible, when putting this in, to connect it with the implant underneath?

    I'm sure someone will be able to shoot these suggestions down pretty quickly, which would be great in itself just to get the ideas out of my head.

  • quoting you: "...obviously transdermal isn't the ideal solution for all the reasons above"

    your suggestion is transdermal, too.
  • edited July 2013
    Transdermal has issues with having a permanently unhealed wound. Something protruding from the skin that the body is fighting against. My first suggestion would be temporary (I didn't really make that clear, my apologies!). A plug, with tapered pins that you could insert through the skin, into the implant. Pain etc aside, would one be able to make connectors capable of transmitting power/date sharp enough for this to work.

    The second are different in that microdermal piercings are a thing that people do to get a similair aesthetic to transdermal.

    As shown here...

    My question was, if this works as a piercing without complication, would it be possible to connect the underside to an implant, creating a bridge through the skin?


    I realised my mistake in regard to your comment. Yes these are transdermal in that they pass through the skin but not the same as many other permanent transdermal implants that cause the common complications.
  • I'll address your second suggestion first. Yes, microdermal implants are transdermal if they go through all layers of the skin as they would need to at dome point to connect with a subdermal implant. They may not require as much aftercare as some larger transdermal implants, but they must be meticulously kept clean to avoid infection. This both proves and disproves the viability of transdermal implants, Yes, they require continuing aftercare and no, the aftercare can become part of a daily hygiene routine, like washing your face and brushing your teeth. Wireless is cleaner, but transdermal is feasible.

    Your other suggestion of using spikes to temporarily connect to a subdermal pad interests me more though. This would be similar to a daily insulin injection. The electrodes do pierce the skin and require a sanitary environment to prevent infection, but not as severe as cleaning a transdermal. The subdermal pads would need to be large enough to allow moving the actual contact point around so that the skin covering them could heal, They would need to provide a low-resistance path to the pads and some insulation to minimize leakage current in the surrounding tissue.
  • Sounds cool, and I think you could cope with the skin getting hurt again and again by having a tattoo at that spot (good to see the position anyway).

    Also, if you use a bigger needle, scar tissue will form, making the entry less painful and blood-less in the future, see this "magic trick" video: 

    This basically means that you it only needs to really hurt once, and after that there is low infection risk as well as other skin issues.

    The real problem is the subdermal pad, you would need some kind of conductive gel, which is very hard and risky not to leak out into the tissue.
    If anyone knows a solution to this, I'd really like to hear it.
  • To deal with the justification for transdermal power a bit more:

    • Roughly half the size of Circadia is in its battery.  An external battery cuts down on implanted size considerably.
    • If a non-battery component suffers significant enough impact to fail you're going to have a nonfunctional component which undergoes rejection, which is unfortunate, but livable...  The same types of damage to a battery means toxic substances in your bloodstream.
  • @Tiak to address the points
    1. The circadia wasn't designed to be small. It's more a slammed together thing made from as many off the shelf components as possible.

    2. the impact required to break a modern battery + mechanical protection + the silicone rubber coating.. chances are you are pretty much dead from the impact in first place.

    even if you want to avoid batteries, inductive charging still offers many advantages over transdermals. most importantly: inductive power transfer works, while transdermals are quite a difficult to deal with.
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