The prevention of cyto- and genotoxicity of nanocarriers is an important task in nanomedicine. In the present
investigation, we, at the first time using similar experimental conditions, compared genotoxicity of nanocarriers with different
composition, architecture, size, molecular weight and charge. Poly(ethylene glycol) polymers, neutral and cationic
liposomes, micelles, poly(amindo amine) and poly(propyleneimine) dendrimers, quantum dots, mesoporous silica, and
supermagnetic iron oxide (SPIO) nanoparticles were studied. All nanoparticles were used in non-cytotoxic concentrations.
However, even in these concentrations, positively charged cationic liposomes, dendrimers, and SPIO nanoparticles induced
genotoxicity leading to the significant formation of micronuclei in cells. Negatively charged and neutral nanocarriers
were not genotoxic. A strong positive correlation was found between the number of formed micronuclei and the positive
charge of nanocarriers. We proposed modifications of both types of dendrimers and SPIO nanoparticles that substantially
decreased their genotoxicity and allowed for an efficient intracellular delivery of nucleic acids.