A study conducted by the Brown University in 2012 showed that nanosilver(ie, Messosilver) is subject to corrosion in acidic environments(such as stomach acid). which in turn, release or produces charged ions(ie, silver salts). And so, the particles that are ingested with silver solutions are not the particles that ultimately cause Argyria. ie, The researchers conducting the study showed that once nanosilver is broken down into the stomach, it is then absorbed into the bloodstream as a salt, which ultimately end-up being deposited in the skin, where it becomes exposed to light, which in turn reduces it back into elemental silver.
As for the bloodstream, I'd question the min. pH levels required to satisfy the reaction. And while it certainly seem as though concentrations play a direct role toward the development of Argyria, I'm really not sure how smaller particles would change the overall potential of the reaction leading up to the condition.
And so, the conclusion seems to be that the bioavailable form of silver absorbed into the bloodstream is a result of the silver salt made in the stomach. And so any elemental silver subject to this particular treatment becomes the raw material from which to produce these compounds. So the ingestion of silver, in any form, be it ionic or not, would result in the same effect. Which leaves us looking at dosage rather than the form of the initial produce(ionic vs particle) as the study implies that silver nanoparticles are likely less toxic than their equivalent amount of silver salt. - Published by The National Science Foundation of Environmental Health Sciences.