Copper is toxic, but at these levels shouldnt be a concern.
Nano stuff are nasty, but since copper in the body cannot last long (corrosive environment), the nano particles will quickly disappear.
This is likely to be far more benign than other nano materials.
The question is, will this survive outside a lab?
If copper found its way into everything as invidiously as pfas has, that would be really bad
Copper is already everywhere at levels far, far above PFAS. It is found naturally in all plants and animals and it has been used for everything from coinage to water pipes for upwards of six millennia.
I wouldn't about it.
PFAS? That's different.
https://en.wikipedia.org/wiki/Polytetrafluoroethylene
> PTFE is one of the best-known and widely applied PFAS commonly described as persistent organic pollutants or "forever chemicals".
PTFE is 100% inert unless heated. It’s the reason why it’s used in joints and stents.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10237242/
> Our review of industry documents shows that companies knew PFAS was “highly toxic when inhaled and moderately toxic when ingested” by 1970, forty years before the public health community. Further, the industry used several strategies that have been shown common to tobacco, pharmaceutical and other industries to influence science and regulation – most notably, suppressing unfavorable research and distorting public discourse.
It took decades for the risks of PFAS materials to properly surface.