The Transferability from Animal Models to Humans: Challenges Regarding Aggregation and Protein Corona Formation of Nanoparticles

Nanomaterials
are interesting candidates for applications in medicine
as drug delivery or diagnostic agents. For safe application, they
have to be evaluated in in vitro and in vivo models to finally be
translated to human clinical trials. However, often those transfer
processes fail, and it is not completely understood whether in vitro
models leading to these animal models can reliably be compared to
the situation in humans. In particular, the interaction of nanomaterials
with components from different blood plasma sources is difficult to
compare, and the outcomes of those interactions with respect to body
distribution and cell uptake are unclear. Therefore, we investigated
the interactions of differently functionalized polymeric and inorganic
nanoparticles with human, mouse, rabbit, and sheep plasma. The focus
was put on the determination of aggregation events of the nanoparticles
occurring in concentrated plasma and the correlation with the respectively
formed protein coronas. Both the stability in plasma as well as the
types of adsorbed proteins were found to strongly depend on the plasma
source. Thus, we suggest evaluating the potential use of nanocarriers
always in the plasma source of the chosen animal model for in vitro
studies as well as in human plasma to pin down differences and eventually
enable transfer into clinical trials in humans.