Whenever i see nano particles used to combat disease, I am always interested in the off target controls. Since they are using physical mechanism to disrupt membrane stability (in the case of bacteria), controlling targeting is very difficult and requires vastly different membrane properties on the surface of bacteria vs regular cells. Issues usually involve lodging of nano particles in the liver or kidneys/ lysis and cytotoxicity . Here they looked at haemolytic and necrotic activities in cells and assessed whether the mice survived- most are short term, and aggregation of nano particles is not uncommon to cause large obvious pathology, it just takes time.
I looked up the core molecule 'PAMAM' or Poly(amidoamine) and it seems to show relatively low cytoxicity, but recent studies seem to shed some more light:
'More recently, a series of studies by Mukherjee et al.[13][14][15] have shed some light on the mechanism of PAMAM cytotoxicity, providing evidence that the dendrimers break free of their encapsulating membrane (endosome) after being absorbed by the cell, causing harm to the cell's mitochondria and eventually leading to cell death. Further elucidation of the mechanism of PAMAM cytotoxicity would help resolve the dispute as to precisely how toxic the dendrimers are.'