Multifunctional iron oxide-carbon hybrid nanoparticles for targeted fluorescent/MR dual-modal imaging and detection of breast cancer cells

An efficient method for the highly sensitive and specific detection of cancer cells is crucial for the early diagnosis of cancer. In this work, we propose a one-pot approach to fabricating magnetic-fluorescent iron oxide-carbon hybrid nanomaterials (MCNP) with excellent stable, high quantum yield and excellent magnetic properties for breast cancer cells recognition and detection via magnetic resonance and multicolour fluorescence imaging. MCNPs were efficiently synthesised via one-pot, multi-component reactions of FeCl3, FeCl2•4H2O, citric acid and ethylenediamine in diethylene glycol. The MCNPs showed strong excitation wavelength-dependent fluorescence in the blue-red region with a high quantum yield of 58.4%, and they presented higher stability and T2 relaxivity than pure iron oxide nanoparticles. After conjugating with CD44 monoclonal antibodies, the fabricated targeting nanoprobe, MCNPs-CD44, demonstrated a specific fluorescence/MRI dual imaging contrast effect in 4T1 breast cancer cells. Biological transmission electron microscope imaging showed a significant preferential uptake of the nanoparticle conjugates by the 4T1 cells. By taking advantage of the high binding affinity and specificity of the CD44 antibodies to the overexpressed CD44 on the cancer cell surface, the developed MCNPs-CD44 probe distinguished 4T1 breast cancer cells from normal cells and detected as low as a few hundred cancer cells, thus indicating the potential application of multifunctional nanocomposites in the MR diagnosis and fluorescence positioning of breast cancer at cellular-level resolution.