Surface-Modified Superparamagnetic Nanoparticles for Drug Delivery: Preparation, Characterization, and Cytotoxicity Studies

TLDR

Superparamagnetic iron oxide nanoparticles have long been employed as MRI contrast agents or in drug delivery. The study reports a novel inverse microemulsion polymerization approach to fabricate magnetic polymeric nanoparticles with a magnetic core and polymeric shell. PEG‑modified superparamagnetic iron oxide nanoparticles were synthesized inside AOT/n‑hexane reverse micelles via inverse microemulsion polymerization of a PEG derivative and cross‑linker, and characterized by TEM, IR, AFM, VSM, and UV/Vis. TEM and AFM confirmed spherical core‑shell particles of 40–50 nm, VSM showed superparamagnetism with 45–50 emu g⁻¹ saturation magnetization, and cytotoxicity assays revealed no toxicity to human dermal fibroblasts, indicating suitability for biomedical use.

Abstract

Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging (MRI) contrast agents or in drug delivery applications. In this study, a novel approach to prepare magnetic polymeric nanoparticles with magnetic core and polymeric shell using inverse microemulsion polymerization process is reported. Poly(ethyleneglycol) (PEG)-modified superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared inside the aqueous cores of AOT/n-Hexane reverse micelles and characterized by various physicochemical means such as transmission electron microscopy (TEM), infrared spectroscopy, atomic force microscopy (AFM), vibrating sample magnetometry (VSM), and ultraviolet/visible spectroscopy. The inverse microemulsion polymerization of a polymerizable derivative of PEG and a cross-linking agent resulted in a stable hydrophilic polymeric shell of the nanoparticles. The results taken together from TEM and AFM studies showed that the particles are spherical in shape with core-shell structure. The average size of the PEG-modified nanoparticles was found to be around 40-50 nm with narrow size distribution. The magnetic measurement studies revealed the superparamagnetic behavior of the nanoparticles with saturation magnetization values between 45-50 electromagnetic units per gram. The cytotoxicity profile of the nanoparticles on human dermal fibroblasts as measured by standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the particles are nontoxic and may be useful for various in vivo and in vitro biomedical applications.