Intranasal delivery of microrobots could trigger new possibilities in treating neurological diseases

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Hongsoo Choi (L) and Seongwoong Jeon (R) of the Department of Robotics Engineering at DGIST in Daegu, South Korea (Credit: DGIST)

A research team in South Korea has developed and successfully implanted a microrobot device into the brain tissue of mice through the intranasal pathway, potentially opening up new possibilities in the treatment of intractable neurological diseases in the future.

Hongsoo Choi (Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology [DGIST], Daegu, South Korea) and Sung Won Kim (Department of Otolaryngology-Head and Neck Surgery, Seoul St Mary’s Hospital, The Catholic University of Korea, Seoul, South Korea) developed a magnetically powered, human nuclear transfer stem cells (hNTSC)-based microrobot.

They also produced a method for the minimally invasive delivery of therapeutic agents into the brain via the intranasal pathway, which bypasses the blood-brain barrier, and were able to transplant their stem cell-based microrobot into the brain tissue of mice with this method.

According to a DGIST press release, the proposed method is superior in efficacy and safety compared to the conventional surgical method, and is expected to enable new possibilities in the treatment of various intractable neurological diseases—including Alzheimer’s disease, Parkinson’s disease and brain tumours.

A key limitation of stem cell therapy is the difficulty in delivering an exact amount of stem cells to an accurate targeted location deep in the body, where the treatment is associated with a high level of risk, the release adds. Another limitation is that both the efficacy and safety of the treatment are low, owing to a large amount of the therapeutic agent being lost during delivery, while the cost of the treatment is also high. In particular, when delivering stem cells into the brain through blood, the efficiency of cell delivery may decrease owing to the blood-brain barrier, which is a unique and specific component of the cerebrovascular network.

To overcome these limitations, the joint research team developed a hNTSC-based microrobot that can be freely and reliably be manipulated within the human body using an external magnetic field. More specifically, it can perform rolling motion by an externally controlled, rotating magnetic field and translational motion by a magnetic field gradient, enabling efficient transport in various physiological environments in vivo. This enables the microrobot to be remotely controlled within the microfluidic channel, facilitating quick and accurate delivery to the target point.

To further verify that the newly developed microrobot could be reliably transplanted into the brain tissue, the research team injected it into mice via the intranasal passage—for the first time in the world, according to the release—and moved the microrobot within their brain tissue using an external magnetic field. This allowed for precise delivery to the cerebral cortex, accomplishing a successful transplantation.

“This research overcomes the limitations in the delivery of a therapeutic agent into brain tissues owing to the blood-brain barrier,” Choi stated. “It opens new possibilities for the treatment of various intractable neurological diseases, such as Alzheimer’s disease, Parkinson’s disease, and brain tumours, by enabling accurate and safe targeted delivery of stem cells through the movement of a magnetically powered, hNTSC-based microrobot via the intranasal pathway.”

The research was supported by the National Research Foundation of Korea, the Ministry of Science and ICT, and the Ministry of Health and Welfare. These results have also been published in Advanced Healthcare Materials.


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