Probing of Interactions of Magnetite Nanoparticles Coated with Native and Aminated Starch with a DPPC Model Membrane

Abstract

Understanding the mechanism of interactions between magnetite nanoparticles and phospholipids that form cellular membranes at the molecular level is of crucial importance for their safe and effective application in medicine (e.g. magnetic resonance imaging, targeted drug delivery, and hyperthermia-based anticancer therapy). In these interactions, their surface coating plays a crucial role because even a small modification to its structure can cause significant changes to the behaviour of the magnetite nanoparticles that come in contact with a biomembrane. In this work, the influence of the magnetite nanoparticles functionalized with native and aminated starch on the thermodynamics, morphology, and dilatational elasticity of the model cell membranes was studied. The model cell membranes constituted the Langmuir monolayers formed at the air-water interface of dipalmitoylphosphatidylcholine (DPPC). The surface of the aminated starch-coated nanoparticles was enriched in highly reactive amino groups, which allowed more effective binding of drugs and biomolecules suitable for specific nano-bio applications. The studies indicated that the presence of these groups also reduced to some extent the disruptive effect of the magnetite nanoparticles on the model membranes and improved their adsorption.

Keywords: Langmuir film; aminated starch; cell membrane; magnetite nanoparticles; nanomedicine; starch.

Figure 1

Structure of the magnetite nanoparticles coated with native starch (Fe₃O₄–S) and aminated starch (Fe₃O₄–AS).

Figure 2

Compression isotherms and compression modulus-surface pressure dependences obtained for the Fe₃O₄–S/DPPC (a,b) and Fe₃O₄–AS/DPPC (c,d) Langmuir monolayers.

Figure 3

Brewster angle microscope images recorded during compression of the DPPC monolayer (a) and Fe₃O₄–S/DPPC films with X_W = 0.02 (b) and X_W = 0.36 (c). Length of scale bar in BAM images—100 µm.

Figure 4

Dependencies of the elastic (E’) and viscous (E”) modulus of the Fe₃O₄–S/DPPC (a) and Fe₃O₄–AS/DPPC (b) films on their composition measured at the different frequencies of the barrier oscillations.

Figure 5

Adsorption kinetics of the Fe₃O₄–S and Fe₃O₄–AS nanoparticles from the water subphase into the DPPC monolayer recorded at the surface pressure of 30 mN·m⁻¹.