> So the question is: how do you detect specifically only cancer cells via lipid nanoparticles?

You don't. Healthy cells will also get these nanoparticles, but without the triggering DNA sequence, the mRNA payload will remain inert and eventually will be degraded.

> Healthy cells will also get these nanoparticles, but without the triggering DNA sequence, the mRNA payload will remain inert and eventually will be degraded.

This is my understanding as well.