Not sure if the spikes can actually detach from the implant, like asbestos fibers, but even if they don't, I was wondering how the tissue surrounding the implant will react to these spikes. Won't they be a constant irritant, which may lead to unwanted consequences? So I agree that further research is probably needed...
The diameter is quite similar - the paper here shows 760 nm which is in the same ballpark as asbestos fibers. Although it seems that lung cancer was more correlated with exposure to longer fibers (>20um) [1], and these are quite short (3.5um) and hopefully not something you inhale.
Since this one is copied off of a design already found in insects, I think we already deal with this pretty well.
How your body handles such dust is simple. We coat it in mucus, and the mucus comes up and out (runny nose, spitting, etc). The reason why asbestos causes problems is that it acts like a needle, and keeps running into things. These are short enough that they shouldn't do that.
Diatomaceous earth works externally to kill bugs who are uniquely susceptible to a powder that is only sharp at a small scale (eg to us it’s a fine powder, to bugs it’s shrapnel). This seems similar but for internal use, so more akin to asbestos in that it’s a tiny sharp object that goes inside us with no clear means of removal. Asbestos is so damaging because our lungs are incapable of removing it, so the fibers irritate structures in the lungs until cancerous cells that can’t be handled by our immune system form and spread. The same principle would apply elsewhere in the body if that irritating object can’t be expunged, I would think. If the body can remove these titanium pieces though, it sounds like it could work well with little to no risk.
The spikes work by "puncturing" bacteria, so viruses, which don't have a cellular membrane, will probably not be affected. But I guess viruses are not their main concern either.
Or even wood. Apparently raw chicken is covered in bacteria, but when testing hours later cutting boards used with raw chicken show no signs of bacteria. So much so the FDA reversed their decision to force commercial food preparations on plastic cutting boards. Turns out the plastic cutting boards absorb bacteria from meat into the cuts the knives use, then they float out when the next piece of meat is cut.
