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BEIJING, Dec. 9 (Xinhua) -- Chinese scientists have developed a targeted delivery system that can bring gene-editing tools to colon cells, offering a precise cure for inflammatory bowel disease.

The study, published on Thursday in the journal Science Advances, reported a CRISPR-Cas9 prodrug nanosystem that can transport a gene-editing protein exclusively to inflammatory lesions in mice colons and then "switch on" the protein.

CRISPR-Cas9 is a gene-editing tool that can be used to edit genes within organisms. One shortcoming of the popular therapeutic tool however is that it can be imprecise, causing unwanted editing at other DNA sites.

Researchers from China's Zhejiang University coated the Cas9 protein with a layer of biomimetic cell membrane where they anchored a small molecule "switch," according to the study.

They found that in mice, a chemical arm of the switch would be activated by stimuli in ulcerative colons, thus activating the Cas9 tool to tone down the expression of disease-causing proteins.

The study revealed that the delivery tool maintains Cas9's high gene-editing level in mice colons while noticeably reducing editing in the liver, lung and spleen.

Using the tool, the unwanted editing in the liver decreased from about 13 percent to 2.6 percent, according to the study.

Yan Xiaojie with Zhejiang University, the paper's first author, told Xinhua that the system might provide a new way to cure refractory colon diseases.

The genome-editing prodrug also presented a proof-of-concept example to precisely regulate CRISPR-Cas9 by particular pathological stimuli in vivo, suggesting therapeutic potential for other diseases like cancers, Yan said.