Iron oxide nanoparticles with different polymer coatings for photothermal therapy

Abstract

Iron oxide nanoparticles (Fe3O4 NPs) have attracted significant attention in view of their potential applications in biomedicine. Surface coatings or modifications are generally needed to improve the colloidal stability of Fe3O4 NPs in a physiological environment. In this study, Fe3O4 NPs in the size range of 12–15 nm coated with polyacrylic acid (PAA), poly(vinyl alcohol) (PVA), and polyethyleneimine (PEI) were synthesized through a mild reduction route to investigate their potential for photothermal therapy. The polymer-coated Fe3O4 NPs dispersed well in water and formed stable colloids; the surface charges of the particles were dependent on the nature of the surface coating. The strong absorption in the near-infrared (NIR) region enabled the coated Fe3O4 NPs to be used as agents in photothermal therapy. The photothermal conversion efficiency of PEI-coated Fe3O4 NPs (PEI-Fe3O4 NPs) distinctly decreased when exposed to a cell culture medium. In addition, PEI-Fe3O4 NPs showed higher cytotoxicity and enhanced cellular uptake efficiency when compared to PAA-coated Fe3O4 NPs (PAA-Fe3O4 NPs) and PVA-coated Fe3O4 NPs (PVA-Fe3O4 NPs). This study highlights the importance of optimizing the surface properties of Fe3O4 NPs when using them in biomedical applications and provides guidelines for the design and development of functional Fe3O4 NPs for cancer therapy.