Methods of acquiring gold and TiN coated N52 + implantation idea + new method of testing coated N52
I have contacted a couple companies willing to do custom orders of coated magnets but they all require minimum purchases that are only feasible in a group purchase. I have found a couple gold plated n52 3mm by 1mm (Same size as m31) and am planning on testing a large batch of around 500 in a heavy salt water solution and a bleach solution and check for impurities in the gold. I'll coat it in a second layer of preferably titanium nitride. One company called azind creates custom N52's of different sizes and coats but only does them wholesale.
If people are willing to do a group buy it's possible I can set up a fairly large and inexpensive way of manufacturing high quality m31 'clones.' Azind is asking for $166 for 100 magnets coated with tin (I am attempting to get a gold and tin coating, and this price is based off of information I got from another user. I am contacting azind to get an exact quote) and the gold plated n52's are only a couple dollars on ebay (obviously these will be tested, don't immediately assume I'm not proceeding carefully. I may also use azind to get the gold coating)
I am also considering using 5 smaller approximately 1.5mm by 1.5mm and placing two of them on each side of the finger and one in the center. This would allow for a large amount of nerves to be stimulated and can give a slightly more 'tactile' feeling to fields. The magnets are to big to fit in the capillaries and would be coated using the method suggested above making them just as safe as the popular m31. More about how this can be successfully done without friction/shifting is talked about later on.
In a later comment I explain a unique method of assuring everybody gets implantable magnets. This solves a large portion of most peoples reluctance to participate in group purchases because they believe it is a gamble.
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There's no guarantee that any of the 100 magnets would be safe to implant so it would be a gamble to all involved.
Bleach is capable of dissolving gold in the right conditions. You might want to research Stannous chloride as a test to tell if any of the gold got dissolved. That solution is very easy (and cheap) to make yourself and is very sensitive to gold in solution.
Both hydrogen peroxide and sodium hypochlorite (bleach) will destroy the
TiN coating, and should be avoided for sterilization. Any sterilization
technique that involves heating (such as autoclaves, boiling, etc.)
will also permanently damage the coating and should not be used.
DangerousThings provides 0.67mL ampoule of ChloraPrep which contains 2%
chlorhexidine gluconate (CHG) and 70% isopropyl alcohol (IPA) and may be
used to sterilize anything with a TiN coating prior to implantation.
Stannous (tin - note small 'n') chloride can be made by dissolving some solder (preferably but not necessarily lead free) in hydrochloric acid. If gold is in solution, a Q-tip can be dipped in the solution and a drop or two of the stannous chloride will turn the Q-tip purple or black depending on the quantity of gold in the solution.
It wouldn't be useful with TiN (assuming bleach is bad for it) but might work for a Parylene C coating over gold. I'm not even sure it would work without testing it myself which would mean sacrificing one or more coated magnets.
Obviously, the whole process of getting biosafe magnets is not easy or there would be more being sold specifically for implanting. The only ones I have heard of at this time is Steve Haworth's.
I personally bought some Parylene coated magnets off ebay but never tried implanting any. I purposely damaged one just to see what kind of reaction I would get with a bad one. Some seemed good but I never fully trusted them and didn't feel like implanting one yet. I was hoping AlexSmith's magnets would test good and be available but his batch didn't test good enough to sell.
It must be harder to do than you are imagining and maybe he could tell you what the problem was or offer things to try to get them done right. Looks like he has been working at this for over a year now and hasn't got them good enough yet.
$300 is not a huge amount of money so maybe you could just save up or borrow the money if you are pretty confident about getting them done right. Wouldn't take very many good ones @$50 each to recover the money and there could be a fair amount of profit if it works and people are confident they are safe.
If I was going to do this myself, I would just risk the $25 and get the 500 gold plated ones and do the initial testing (whatever that would be) and see how many of them appear good. Post the results here and others may jump in to help fund the rest of the costs.
I have a feeling there are a number of members here working on DIY coatings but probably too risky to sell.
A couple/few more people willing to try this and you will be at your goal.
Obviously, we will each want to do our own testing before implanting these but who knows ... It might be the way to get the magnets everyone has been waiting for.
I know you are not interested in DIY coatings but I contacted Atom Adhesives asking about anything that their food/medical grade epoxy would not stick to which might be usable as a mold for casting the resin. They replied "This product does not stick very well to rubber and very hard plastics."
I'm more interested in sensing magnetic fields than lifting things with a magnet implant and I would assume smaller magnets would require less cutting to implant but not much difference unless maybe using a needle to implant it.
Does the titanium coating process involve heat that could reduce the magnetic rating? Part of the appeal of TiN was that it was applied at room temperature.
Wouldn't it be better to forgo the Au layer? Not only is it creating an extra layer (albeit, a thin layer), of inert (and again, albeit biocompatable) material that reduces magnetic volume, but also creates a weaker sub surface to build off of? It's like pouring concrete over a layer of sand instead of a layer of compacted dirt, for sake of describing Ni versus Au... TiN is strong but brittle. If it's adhered to a weak surface, and granted this is microscale, I can still see faults arising. #_#
Also, are these magnets running Ni-Cu-Ni undercoat beneath the Au? And IF so, can these be removed at all, replaced with NdFeB strait to shell? The Ni-Cu-Ni only adds further inert material that reduces magnetic density.
Surface area to volume adds up really quickly to create less efficient magnets. Played around a ton with the math to find that coatings can wreck magnetic density efficiency. C_c
Also would highly suggest testing magnetic strength before and after coatings, we should be able to calculate rough drop off from coating thickness, and confirm lack of magnetic strength deterioration. ^^'
Add another 20 micron thick layer for Ti. You just took it down to just under 88% magnetic material. ;_;
Adding a .5mm shell to an M31 drops it's magnetic mass to less than 30% by volume. Surface area to volume is scary. :c
By my calculations, only $10 or $20 more to get to the $220 goal to get this latest attempt to get implantable magnets to happen.
Anyone else want in on this?