Novel Nanocomposite Developed for Magnetic Resonance Tumor Imaging (Physics)

A research team led by Prof. LIANG Changhao from the Institute of solid State Physics of the Hefei Institutes of Physical Science (HFIPS) successfully obtained Mn3O4/PtOx nanocomposites (NCs) which paved the way for the practical clinical applications for Mn3O4 nanosturctures in magnetic resonance (MR) imaging.

Manganese oxide (Mn3O4) nanoparticles have received widespread attention as Contrast agents (CA) of MR imaging. However, for better bio-safety, Mn3O4 nanoparticles must have small hydrodynamic particle size and compatible surface modification, which possibly make it difficult for Mn2+ ions on the particle surface to chemically exchange with water molecules under the magnetic field. Thus, the contrast performance of Mn3O4 nanoparticles in MR imaging is often not qualified for clinic use.

In this research, the researchers used laser fabrication technology to obtain defect-rich Mn3O4 nanoparticles as precursors to obtain Mn2+-based porous nanostructure with payload of the platinum oxide (PtOx) nanoparticles via the ion exchange reaction.

Schematic of the MR contrast affected by q and τr before and after ion etching. (Image by CAI Yunyu)

They called it Mn3O4/PtOx NCs whose longitudinal relaxivity (r1) and transverse relaxivity (r2) ratio (1.46) was proved much lower than the value 2.61 for the commercial Gd-DTPA.

“It indicates that Mn3O4/PtOx NCs show obvious superior contrast performance than commercial product in MR imaging experiment.” said LIANG Changhao, who led the team.

The team further analyzed the reason behind the phenomenon based on the structure-relaxivity relationship for inorganic nanostructure. They found that surface morphology could increase coordinated number of water molecules and surface payload could prolong the tumbling time. Both could benefit to increase the T1 relaxivity.

As the higher porosity of the NCs indicated more PtOx payload, the surface morphology and the payload synergistically increased the T1 imaging contrast potency of the Mn3O4/PtOx NCs.

These novel findings showcase a brand-new strategy for fabricating excellent manganese-based CAs on the basis of the surface structure.

The research was supported by the National Natural Science Foundation of China.

Featured image: Schematic of formation for Mn3O4/PtOx NCs by laser fabrication in liquids technology. (Image by CAI Yunyu)


Reference

Surface morphology and payload synergistically caused an enhancement of the longitudinal relaxivity of a Mn3O4/PtOx nanocomposite for magnetic resonance tumor imaging


Provided by Chinese Academy of Sciences

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