Nanoscale engineering of hybrid magnetite–carbon nanofibre materials for magnetic resonance imaging contrast agents

Abstract

Magnetic nanomaterials show significant promise as contrast agents for magnetic resonance imaging (MRI). We have developed a new highly efficient one-step procedure for the synthesis of magnetically-functionalised hollow carbon nanofibres, where (i) the carbon nanofibres act as both a template and a support for the nucleation and growth of magnetite nanoparticles and (ii) the structural (size, dispersity and morphology) and functional (magnetisation and coercivity) properties of the magnetic nanoparticles formed on nanofibres are strictly controlled by the mass ratio of the magnetite precursor to the nanofibres and the solvent employed during synthesis. We have shown that our magnetitenanofibre materials are effectively solubilised in water resulting in a stable suspension that has been employed as a "negative" MRI contrast agent with an excellent transverse relaxivity (r 2 ) of (268 ± 13) mM/s, surpassing current commercial materials and state-of-the-art magnetic nanoscale platforms in performance for MRI contrast at high magnetic fields. The 2 preparation and evaluation of this unique hybrid nanomaterial represents a critical step towards the realisation of a highly efficient "smart" MRI theranostic agent -a material that allows for the combined diagnosis (with MRI), treatment (with magnetic targeting) and follow-up of a disease (with MRI) -currently in high demand for various clinical applications, including personalised nanomedicine.

Interplay of cell death signaling pathways mediated by alternating magnetic field gradient

“…In recent years, magnetic nanoparticles (MNPs) have rapidly gained traction in the biomedical fields as magnetic resonance imaging contrast agents 1 , 2 , biosensors 3 , 4 and controlled drug delivery 5 , 6 . In addition, MNPs with engineered magnetic properties and high biocompatibility have been shown to be a promising candidate for cancer treatment.…”

Recent progress in imaging technology combined with nanomaterials for medical applications

“…According to the magnetic composition, MRI contrast agents can be divided into three categories: paramagnetic, ferromagnetism, and superparamagnetism. Metelkina et al [5] developed a magnetite‐nanofiber material which was tested as an MRI contrast agent. The relaxivities r 1 = (0.7 ± 0.3) mM s −1 and r 2 = (268 ± 13) mM s −1 were determined by linearly fitting the data.…”

Carbon Nano-Allotrope/Magnetic Nanoparticle Hybrid Nanomaterials as T2 Contrast Agents for Magnetic Resonance Imaging Applications

“…The silica coating layer introduces many benefits, including preventing the leakage of the nanoparticles from the GNF hollow cavity, protecting the Fe 3 O 4 NPs from damage in harsh acidic conditions, and increasing the biocompatibility and stability of the nanocomposites. In another work, Khlobystov et al performed a detailed study on the controlled preparation of Fe 3 O 4 -GNF nanocomposites [ 69 ], in which hollow CNFs acted both as a template and a support for the nucleation and growth of Fe 3 O 4 NPs. The influence of solvent type and the mass ratio of the magnetite precursor on the structures (size, dispersity, and morphology) and physical properties (magnetization and coercivity) of the Fe 3 O 4 -GNF products were systematically studied.…”