The Shenyang Institute of Automation of the Chinese Academy of Sciences, in collaboration with Shengjing Hospital of China Medical University, has successfully developed a diatom-derived magnetic biohybrid microrobot for photodynamic therapy of glioblastoma.

Glioblastoma is a highly aggressive, malignant and fast-growing brain tumor. The research result was published online by the international academic journal Bio-Design and Manufacturing in February.

Through deep integration of life science and robotics technology, the breakthrough marks an important step for Liaoning province in the research and development of high-end medical equipment. It also provides a new Chinese solution for the precise treatment of glioblastoma, a challenge that has long been faced by the medical community due to the complexity of lesion areas and the difficulty for drug delivery.

The research team innovatively used diatoms, a porous and single-celled organism found in nature, as the structural base for the microrobots. They are among the smallest photosynthetic organisms on the planet and are widely distributed in environments such as oceans, lakes and wetlands.

Diatom cells resemble small porous boxes, with an external shell composed of silicon dioxide that is colorless, transparent and hard. Under a microscope, the diatom shell exhibits a variety of structural patterns with uniform micropores, making it a natural container for drug loading and targeted delivery.

Applying artificial intelligence algorithms, researchers endowed the diatom microrobots with autonomous closed-loop motion capabilities. The microrobots then exhibited excellent magnetic responsiveness and programmable motion capabilities, enabling them to precisely target and navigate to glioblastoma lesion areas.

According to Jiao Niandong, a researcher at the institute, endogenous chlorophyll inherent in the diatoms is utilized as a natural photosensitizer, achieving photodynamic therapy against glioblastoma without the need for additional drug modification.

Animal experimental results have shown that laser-activated diatom microrobots had a significant killing effect on primary glioblastoma cells, reducing their survival rate to 19.5 percent. The experiment further verified that the microrobots, which possess excellent bio-compatibility, can effectively inhibit tumor growth without causing significant systemic toxicity.

"This type of microrobot that does not require exogenous drug delivery can, to some extent, avoid the risk of drug leakage in targeted delivery and reduce the risk of damaging normal tissues and cells," Jiao said.

"Under precise control of an external magnetic field, they can navigate through narrow tissue gaps and move along a preset trajectory to the glioblastoma lesion area. Once the diatom microrobots reach the lesion, laser activation of the chlorophyll induces a photodynamic effect, precisely killing cancer cells."

Jiao added that the achievement could be combined with intraoperative navigation and in vivo remote delivery technologies to further enhance targeting and efficacy, providing a novel automated solution for the clinical treatment of glioblastoma.

Contact the writers at zhouhuiying@chinadaily.com.cn