Research not cited here has demonstrated that cultured human keratinocytes remain undamaged and viable after exposure to the Biogun many times longer and more potent than any encountered in clinical practice.
But what is the Biogun doing to the inside of a healthy cell? Could it, for example, be altering its DNA and causing it to mutate or become cancerous? The short answer is that it is doing nothing at all to a healthy cell's insides, and the scientific way of proving this is to conduct what is called a Comet Assay. Because the Biogun is used in dentistry, the cells chosen for test were treated in situ on the buccal mucosa (the inside of the cheek). A substantial series of experiments found no effect at all on the internal workings of the cells. The evidence itself is available here.