A collaborative study team with Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science (CASHIPS)  and Shanghai Jiao Tong University School of Medicine developed a pH-responsive drug-free theranostic agent which could be not only a good replacement for traditional chemotherapeutics but also a promising candidate for the visualization therapy of tumor by magnetic resonance imaging (or MRI).

This work was done by WU Zhengyan of CASHIPS and his colleagues. They made the theranostic nanoplatform via nanoselenium-coated manganese carbonate-deposited iron oxide nanoparticles (MCDION-Se).

The traditional chemotherapeutic drugs are significantly limited in terms of clinical application for high prices and serious side effects. Therefore, drug-free therapeutic agents with low cost and less side effect are in high demand for cancer treatment.

In WU’s work, they integrated chemical dynamic therapy (CDT) with limotherapy and tumor-specific MRI to make the theranostic nanoplatform which could be a help hand in cancer treatment.

According to their study, MCDION-Se showed multiple functions, namely, CDT, limotherapy and pH-responsive MR imaging for cancer.

It effectively released Mn²⁺ ions in the tumor microenvironment, making it a precise diagnostic platform for tumor.

The loaded nano-Se could rapidly activate superoxide dismutase (SOD) and promote the generation of superoxide anion radicals (SOARs), which triggered a cascade reaction to form H₂O₂.

Meanwhile, Mn²⁺ ions and ION further catalyzed the decomposition of H₂O₂ into highly toxic ·OH, which would cause the fast oxidation and deterioration of proteins and enhance the therapeutic efficiency of CDT.

In addition, the Mn²⁺ ions and nano-Se in tumor cells also significantly limited the generation of ATP, thus starving the tumor cells.

This research was supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences, the Science and Technology Major Project of Anhui Province, the Natural Science Foundation of Anhui Province, and the National Natural Science Foundation of China.

Schematic illustration of the cascade reaction of MCDION-Se in the intracellular environment. (Image by XIAO Jianmin)