Diatoms are unicellular, porous single-celled organisms, typically ranging from several to tens of micrometers in size. As one of the smallest photosynthetic organisms on Earth, they are widely found in marine, freshwater, and wetland environments. A diatom cell resembles a tiny, porous box. Its outer cell wall, known as the frustule, is composed of colorless, transparent, and rigid silica. Under a microscope, diatom frustules display a rich variety of structures featuring uniform micropores.

Recently, a research team from the Laboratory of Robotics at the Shenyang Institute of Automation (SIA), Chinese Academy of Sciences(CAS), in collaboration with Shengjing Hospital of China Medical University, has developed a novel diatom-based microrobot for the treatment of brain glioma. These microrobots exhibit excellent magnetic responsiveness and programmable motion capabilities, enabling them to precisely target and navigate to glioma lesion areas. Furthermore, they can utilize endogenous chlorophyll inherent in the diatoms as a natural photosensitizer, achieving photodynamic therapy (PDT) against glioblastoma without the need for additional drug modification. Animal experiments have shown that the diatom robot produced a significant killing effect on primary glioma cells and demonstrated good biocompatibility.

Schematic illustration of Mag-Diatom-mediated PDT (Image by SIA)

The researchers fabricated micro/nano-scale robots from diatoms using acid treatment technology. The inherent porous structure of the diatoms allows for drug loading, while an external magnetic field is employed to control their movement, granting them the capability for precise drug delivery. During the fabrication process, the natural chlorophyll carried within the diatom cells was intentionally preserved, serving as a natural "drug." By leveraging artificial intelligence algorithms, the diatom robots achieve autonomous closed-loop motion, enabling controlled navigation along preset trajectories. The microrobots also demonstrated the ability to traverse narrow gaps and target cancer cells within a cellular environment.

The researchers conducted animal experiments by injecting the diatom robots into the intracranial glioma lesions of mice and activating photodynamic therapy using a laser. The experimental results showed that the laser-activated diatom microrobots produced a significant killing effect on primary glioma cells, reducing the survival rate of primary cells to 19.5%. The experiments further validated that the diatom microrobots could effectively inhibit tumor growth without causing significant systemic toxicity.

The findings were published online in the international academic journal Bio-Design and Manufacturing on February 16, 2026.

"This type of microrobot, which does not rely on exogenous drug loading, can potentially circumvent the risks of drug leakage associated with targeted delivery, thereby reducing the risk of damage to healthy tissues and cells," said Professor JIAO Niandong, a researcher at SIA. In the future, by combining this technology with intraoperative navigation systems and techniques for long-distance in vivo delivery, the team aims to enhance its targeting capability and therapeutic efficacy.