In recent years, there has been increased use of magnetic nanoparticles (NPs) geared towards biotherapeutic application including MRI, hyperthermia treatments, magneto-targeted therapy and drug delivery. Nanoferrites... [ view full abstract ]
In recent years, there has been increased use of magnetic nanoparticles (NPs) geared towards biotherapeutic application including MRI, hyperthermia treatments, magneto-targeted therapy and drug delivery. Nanoferrites comprising CoFe2O4 core, have been shown to present unique properties such as their facile synthesis, large surface-to-volume ratio and high magnetisation saturation. With precise engineering by conjugation with various molecules, specificity, optical detectability, longer circulation times and therapeutic delivery are made possible. Targeted therapy using an external magnetic field presents for an attractive feature in biotherapeutic applications. Chitosan is a natural polymer, which is non-toxic, biodegradable and biocompatible. It has been extensively explored for use as a polymer of choice, and recently in combination with magnetic NPs.
In this study, the glycol-thermal method was employed to synthesise MgFe2O4 and Mg0.5Co0.5Fe2O4 NPs. Comparative analysis was conducted, following coating of the synthesised NPs with chitosan. Analytical characterisations were performed using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), High Resolution TEM (HR-TEM) and Scanning Electron Microscopy (SEM). Magnetisation properties were analysed using the Vibrating Sample Magnetometer (VSM). Nanoparticle Tracking Analysis (NTA) was employed to measure stability of the NPs.
Synthesis of NPs was confirmed to be single phase formation. XRD revealed spinel structure of MgFe2O4 and Mg0.5Co0.5Fe2O4 with the average crystallite size diameter of 13 nm. The chitosan layer on the surface of NPs was confirmed by FTIR with additional peaks characteristic of chitosan and ferrites. TEM, SEM and HR-TEM results for both coated and uncoated NPs showed spherical morphology and sizes not more than 20nm in diameter. VSM indicated superparamagnetic characteristics of the nanoparticles with magnetisation saturation of up to 70 emu/g. These were marginally reduced in coated NPs, also attributed to chitosan. NTA results revealed relatively stable NPs where agglomeration was reduced in coated NPs. The naked and coated NPs were better tolerated in some cell lines at varying concentrations. In conclusion, all NPs hold much potential as nanocarriers of choice for targeted gene and drug delivery. By enhancing biodegradability and biocompatility of these NPs through chitosan-coating, this allows for a more attractive and feasible bio-application for these nanoferrites.
