Can you explain the relevance of this question? I think it’s likely I’m missing something, but your question sounds like: “Yes, volcano eruptions have killed innumerable people and species…but were they _specifically engineered_ as killing machines?? Gotcha!”

here's the relevance :

a bow and arrow and a gun both shoot projectiles. One of them has more regulation due to improved efficacy at shooting projectiles.

The presumption here would be that the materials designed for killing cells would do so in a drastically better fashion than materials that are designed for better brake performance but which also coincidentally shed harmful particles.

Using your concept : it would raise questions if we heard about a human-lead effort to develop the most cataclysmic volcano eruption ever produced.

I didn't get the premise that it's supposed to be a gotcha; it's not. It's just a different thing. We gain benefit from better brakes, it's not all loss.

But at these length scales these materials are very corrodable, even stainless steel. They wont last long in the body.

Unlike, say, textures silica that was on here a few months ago. Then I raised this exact concern since SiO2 wont just disappear.

Engineered? It's metallic copper.

And “nanotextured stainless steel”?

Asbestos is just… rock.

Yes. They etched stainless steel.

I'm not seeing the comparison to asbestos which is dangerous regardless of form.

Asbestos is dangerous because of its form. It isn’t inherently toxic, it just pokes your lung tissues to death.

This is why I find a new material with “nanoprotrusions measuring 20–30 nm” in an article talking about “nanodaggers” killing cells somewhat concerning.

Specifically SiO2 which does not dissolve

Is rock safe?

Against scissors, yes.