A detailed investigation on interactions between magnetite nanoparticles functionalized with aminated chitosan and a cell model membrane.

Magnetite nanoparticles are promising materials for application in magnetic resonance imaging, targeted drug delivery, enzyme immobilization and cancer therapies based on hyperthermia thanks to their biocompatibility, wide chemical affinity and superparamagnetic properties. However, there is still the lack of the knowledge of interactions between magnetite nanoparticles covered with the bioactive polymers and biological cells. In order to fulfil this gap, we have investigated interactions of newly synthetized magnetite nanoparticles functionalized with aminated chitosan (Fe3O4-aminated chitosan) and a model biological membrane made of dipalmitoylphosphatidylcholine (DPPC) using a Langmuir technique. Surface pressure-mean area per DPPC molecule isotherms and Brewster angle microscope images (BAM) recorded during compression of the two-component Fe3O4-aminated chitosan:DPPC films revealed the strong influence of the Fe3O4-aminated chitosan nanoparticles on the stability, phase state and structure of the phospholipid membrane. The studies on the adsorption/incorporation process of the Fe3O4-aminated chitosan nanoparticles showed that they can adsorb/incorporate into the DPPC model membrane at the surface pressure corresponding to this present in the cellular membrane under the biological conditions (35 mN·m-1). The number of the adsorbed/incorporated Fe3O4-aminated chitosan nanoparticles can be regulated by the nanoparticles concentration in the neighbourhood of the DPPC model membrane even at high surface pressure of 35 mN·m-1.