Influential factor Effect for experimental systems in vitrotest in vivotest  
Adsorption ability (Proteins, salts) Adsorption of molecules to particles Yes Yes primary effect
Influence of adsorption effect on experimental result. (Starvation effect, adsorption of marker molecules, etc.) Yes No confounding effects (artificial)
Metal ion release Metal ion release from nanoparticles Yes Yes primary effect
Accumulation of metal ions in experimental system Yes No confounding effects (artificial)
Influence to experimental reaction such as ELISA Yes No confounding effects (artificial)
Stability of nanosuspension Formation of secondary particles, aggregates and/or agglomerates Yes Yes primary effect
Accumulation of the large secondary particles onto cells by gravitational settling Yes No confounding effects (artificial)
Table 1: Important factors of nanotoxicology and these effects on experimental systems.