Chinese scientists develop nanozymes to target tumor cells

BEIJING - Nanozymes, nanomaterials with intrinsic enzyme-like activities, have been widely used in cancer diagnosis in recent years, but controlling their performance in treating a target tumor cell remains a challenge.

A research team, jointly led by Yan Xiyun from the Institute of Biophysics under the Chinese Academy of Sciences and Gao Lizeng from Yangzhou University, has for the first time developed a strategy to coordinate nanozymes to target tumor cells and selectively kill tumors. Their findings were published in Nature Communications last week.

During tumor growth and development, elevated levels of hydrogen peroxide (H2O2) are often exhibited in solid tumors, which render tumor cells more resistant to therapeutic treatment.

This situation reduces the effect of chemotherapy. If the accumulated H2O2 can be combined with oxygen to be converted into a toxic reactive oxygen species, this may enable more effective means of tumor therapy, according to Yan.

Previously natural enzymes were used, however, they were less sensitive and not as stable, so enzyme mimics or artificial enzymes were developed, but the efficiency of enzyme mimics was often insufficient.

Therefore, the team has developed a nanozyme which has shown excellent bio-compatibility.

To optimize its performance for tumor therapy, scientists used ferritin, an intracellular protein found in most human tissue, to modify the surface of the nanozymes to enable them to target tumors.

Tests demonstrated that ferritin-modified nanozymes suppressed tumors in animal models, and proved the feasibility of using nanozymes for tumor therapy.

"If modified, nanozymes can function as Trojan horses, transporting cell-destroying compounds into tumor cells," said Yan.

Nanozymes can be fine-tuned via size, dosage, and surface modification. In addition, they have multiple functions, high stability, and are easy to scale up at a low cost, according to the study.

"We hope this nanozyme-based tumor therapy can enable new strategies for cancer treatment," Yan said.