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Magnetically Actuated Microrobots: A New Mode for Stem Cell Transplantation

For the first time, scientists successfully transplanted stem cell-based microrobots efficiently, non-invasively, and safely into mice brain tissues to treat neurological diseases.

A joint research team, led by Professor Hongsoo Choi at Daegu Gyeongbuk Institute of Science and Technology and Professor Sung Won Kim at Seoul St. Mary’s Hospital, has developed a magnetically powered human nuclear transfer stem cells (hNTSC)-based microrobot that can be used to deliver therapeutic agents into the brain via the intranasal pathway. The team successfully bypassed the blood-brain barrier and transplanted the developed stem cell-based microrobot into the brain tissues in an efficient and minimally invasive fashion.

Stem cell therapy, also known as regenerative medicine, is designed to repair the response of damaged, diseased, or dysfunctional cells in the body by reducing inflammation and modulating the immune system. In recent years, this form of therapy has become a very promising and advanced field of scientific research and raised great expectations for potentially curing presently untreatable diseases like leukaemia and other types of cancer.

However, translating stem cell therapy into clinical practice has been difficult as many aspects of the treatment have raised concerns. For one, delivering a precise amount of stem cells to a targeted location deep in the human body accurately is an incredibly challenging task. The efficacy and safety of stem cell therapy are also reportedly low since large amounts of the therapeutic agent are often lost during delivery. In the specific case of delivering stem cells into the brain via the bloodstream, the blood-brain barrier may reduce therapeutic efficiency. Moreover, the cost of treatment is high.

To solve these problems, Prof. Choi, Prof. Kim, and colleagues developed an hNTSC-based microrobot that can be freely and reliably controlled within the human body using an external magnetic field. The team developed the microrobot by internalising iron oxide nanoparticles that exhibit high biocompatibility and superparamagnetism into stem cells that were derived from human nasal turbinate.

Through a series of tests, they found that the microrobot can be directed to perform rolling and translational motions using an externally-controlled rotating magnetic field and a magnetic field gradient respectively. This would enable the microrobot to efficiently transport substances in physiological environments in vivo and allow for its remote control within the microfluidic channel, thereby facilitating quick and accurate delivery to specific target points.

To test the efficacy and safety of their technology, the team injected the microrobot into mice via the intranasal passage that bypasses the blood-brain barrier. Using an external magnetic field, they moved the microrobot within the brain tissue and precisely delivered the stem cells to the cerebral cortex.

As the first attempt of its kind, their experiment successfully demonstrated that new microrobots could be reliably transplanted to the brain tissue. By overcoming the challenges currently faced in the delivery of therapeutic agents into brain tissues, the scientists are hopeful that their innovation could pave the way towards more efficient treatment approaches.

“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,” said Prof. Choi. [APBN]

Source: Jeon et al. (2021). A Magnetically Powered Stem Cel-Based Microrobot for Minimally Invasive Stem Cell Delivery via the Intranasal Pathway in a Mouse Brain. Advanced Healthcare Materials, 10(19), 2170089.