Negatively charged magnetic nanoparticles pass the blood-placenta barrier under continuous flow conditions in a time-dependent manner

The transfer of substances via the blood-placenta barrier is tightly regulated and critical for the fetus and the expecting mother. In case of necessary medical interventions during pregnancy a comprehensive knowledge about the interaction of the drugs with this barrier is indispensable. Therefore well-engineered test systems are needed and valuable transport systems are helpful. We developed an in vitro microfluidic blood-placenta barrier system consisting of the human trophoblast cell line BeWo and human primary placental pericytes. The integrity and stability of the model was verified by a permeability assay and immunocytochemistry. As potential drug carriers magnetic nanoparticles with various coatings were applied and their ability to pass the barrier was quantified by magnetic particle spectroscopy. We could demonstrate that up to 4% of negatively charged nanoparticles pass the barrier in a time-dependent manner.