Chitosan-coated magnetic nanorods and nanospheres: physicochemical characterizations and potential as methotrexate carriers for targeted drug delivery

Abstract Spherical magnetite nanoparticles were employed in the almost all magnetic based drug delivery studies. But as we all know the shape of employed particles is one of the major deterministic properties that can significantly affect the physicochemical and biological features of nanostructures and so can fluctuate efficiency of drug delivery. However, it is worthy of consideration that so far no study has investigated the effect of the shape of nanoparticles in drug delivery. To some extent this deficiency in publications may be due to the fact that the synthesis of other forms of magnetite nanoparticles is not as developed as spherical nanoparticles. But recent experiments paved the way for the synthesis of magnetite nanoparticles specially magnetite nanorods (MNRs). So, for the first time, in the current experiment magnetite nanospheres (MNSs) and MNRs were compared in the potential for drug delivery. Chitosan is a natural and biocompatible compound that widely employed as coating material for the fabrication of anticancer drug nano-carriers. So in the present study this carbohydrate was chosen as coating material for the magnetic nanostructures. MNSs were synthesized via a co-precipitation reaction, and MNRs were obtained from the chemical reduction of iron oxide hydroxide (FeOOH) nanorods. Both nanostructures were loaded with methotrexate (MTX), and the release of the drug was measured. The chitosan-coated MNSs (C@MNSs) were 7–18 nm in diameter, and the chitosan-coated MNRs (C@MNRs) were 5–21 nm in width and 29–108 nm in length and had a porous structure. The C@MNSs had a magnetic saturation of ∼80 emu/g, whereas that for the C@MNRs was ∼45 emu/g. The synthesized nanostructures exhibited low toxicity and were able to release the drug inside the cells. The findings of this study demonstrate the suitability of C@MNRs as an alternative to spherical nano-carriers for the efficient and contained delivery of anticancer drugs to designated target cells.