Sorry about the thread necromancy, but this seems to be the main place to chat about magnetic tattoo ink.
Turns out, you can get ferromagnetic particles in a tattoo to interact with a magnetic field, and if the magnetic field is big enough, it sucks for the person with the tattoo: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445217/
I was kind of hoping for a easy way to couple magnetic drivers to skin for haptics, but it looks like there's either an ohmic heating thing going on with the induced current (I imagine on a per-particle basis, rather than in loop circuits), or the field is actually dragging the ink within the skin and causing trauma that way.
From the paper: "The authors further confirmed a ferromagnetic property of the tattoo pigment by documenting migration of the ellipsed skin toward a standard horseshoe magnet. They further studied the ferromagnetic properties of common tattoo pigments and showed that iron oxide–based pigments (most commonly black and brown) were displaced by a magnetic field, whereas carbon-, titanium-, and copper-based pigments were unaffected." So ferromagnetic ink is already a thing you can buy, and a normal magnet is sufficient to drag the skin holding the ink around.
Comments
Turns out, you can get ferromagnetic particles in a tattoo to interact with a magnetic field, and if the magnetic field is big enough, it sucks for the person with the tattoo: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445217/
I was kind of hoping for a easy way to couple magnetic drivers to skin for haptics, but it looks like there's either an ohmic heating thing going on with the induced current (I imagine on a per-particle basis, rather than in loop circuits), or the field is actually dragging the ink within the skin and causing trauma that way.
From the paper: "The authors further confirmed a ferromagnetic property of the tattoo
pigment by documenting migration of the ellipsed skin toward a standard
horseshoe magnet. They further studied the ferromagnetic properties of
common tattoo pigments and showed that iron oxide–based pigments (most
commonly black and brown) were displaced by a magnetic field, whereas
carbon-, titanium-, and copper-based pigments were unaffected." So ferromagnetic ink is already a thing you can buy, and a normal magnet is sufficient to drag the skin holding the ink around.