I've read recently that QAS (quaternary ammonium salts) are commonly used as a sterilizer because they are not toxic against animals and humans. They act as “contact-killers” by either breaking through a cytoplasmic membrane or causing disorder in the cell wall function.

So my question is: It does not affect humans and animals because they have more cells than one, so the loss is not so crucial, like in the case of bacteria OR the animal cell wall is built differently, and the QAS does them no harm, even when separated? Would it affect one cell, i.e., when it comes to endothelialization or when contact with blood cells or stem cells?