A novel method using carbon-coated magnetite nanoclusters has been suggested as suitable in cancer synergistic therapy

Recently, Professor Wang Hui, together with Professor Lin Wenchu and Associate Professor Qian Junchao from Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Sciences reported a NIR- II -responsive carbon-coated iron oxide nanocluster which was guided by magnetic resonance image and capable of combined photothermal and chemodynamic therapy (CDT).

As a promising treatment strategy, CDT has become a hot spot in treating cancer because of its simple operation and low side effects.

The basic principle of CDT is that the nanozymes activate intracellular Fenton reaction, leading to the over-production of hydroxyl radicals that are toxic to cancer cells.

Magnetite nanocrystals are widely used as Fenton reagents due to their non-invasive imaging ability and good biocompatibility.

However, the ferromagnetic behaviour and easy oxidisation of magnetite nanocrystals bring about colloidal instability as nanozymes and limit the imaging-guided cancer therapy in practical application.

See also: Heat-efficient nanoparticles for treating cancer developed

one-stop solvothermal method

In this research, the team used a one-step solvothermal method to produce carbon-coated magnetite nanoclusters (CCMNCs) with optical absorption in the NIR-II(1000-1100 nm) by tuning the cluster structure and carbon coating of magnetite nanocrystals.

Wang Hui, who led the team, said: “The CCMNCs possess superparamagnetic nature and a rapid magnetic response for separation, enabling them as a contrast agent for T2-weighted MRI.”

He further explained how the CCMNCs worked.

  • Fe2+and Fe3+ could be found in the dissolution of CCMNCs in tumour microenvironment.
  • Fe2+produced ·OH in situ in cells and mice, which in turn killed cancer cells and inhibited tumour growth through CDT effects.
  • Fe3+could reduce intracellular glutathione (GSH) levels and enhance the deleterious effects caused by ·OH, thus improving CDT efficiency.

The authors concluded that the CCMNCs could effectively absorb and convert NIR-II irradiation into cytotoxic heat, enhancing tumour CDT efficiency and producing synergistic therapeutic effects.

The research results are published in Science China Materials.

Image: Schematic diagram of the CCMNCs for MR imaging, NIR-II-induced PTT-enhanced CDT. © Lin Yefeng.