Magnetically controlled insertion of magnetic nanoparticles into membrane model

Polysaccharide–coated magnetic nanoparticles (MNPs) have been reported to show potential applications in many biomedical fields. In this report, we have studied the interactions between magnetite (Fe₃O₄) MNPs functionalized with polysaccharides (diethylamino–ethyl dextran, DEAE–D or chitosan, CHI) with different membranes models by Langmuir isotherms, incorporation experiments, and brewster angle microscopy (BAM). In this report, zwitterionic 1,2–distearoyl–sn–glycerol–3–phosphoethanolamine (DSPE) and anionic 1,2–distearoyl–sn–glycerol–3–phosphate (DSPA) phospholipid, were used to form membrane models. Incorporation experiments (π–t) as well as the compression isotherms demonstrate positive interactions between MNPs and DSPE or DSPA monolayers. The study assessed the impact of varying initial surface pressure on a preformed phospholipid monolayer to determine the maximum insertion pressure (MIP) and synergy. Our findings indicate that the primary driving force of the coated MNPs incorporation into the monolayer predominantly stems from electrostatic interaction. The drop in the subphase pH from 6.0 to 4.0 led to an enhancement of the MIP value for DSPA phospholipid monolayer. On the other hand, for DSPE, the drop in the pH does not affect the MIP values. Besides, the presence of a magnetic field induces an enhancement of the insertion process of the MNPs into DSPA preformed monolayer, demonstrating that a previous interaction between MNPs and phospholipid preformed monolayer needs to take place to enhance the incorporation process. This work opens novel perspectives for the research of the influence of magnetic fields on the incorporation of MNPs into model membranes.