Have you heard of deep brain stimulation (DBS)? For certain neurological movement disorders like Parkinson’s disease, DBS is an effective treatment in which doctors directly stimulate the affected motor areas of the brain electrically. 

Traditionally, stimulating motor cells requires significant effort. Devices that directly stimulate these cells often need to be surgically implanted and removed, which carries risks such as infection, tissue damage, and complications when the implants are long-term. Devices that stimulate cells through the skull, on the other hand, are generally less accurate.

A group of researchers under Professor Cindi Morshead of the Department of Surgery have developed biodegradable electrodes capable of stimulating a type of brain cell known as neural precursor cells (NPCs). NPCs include two different cell types: endogenous neural stem cells and neural progenitor cells. These two cell types differentiate into most cells that populate the central nervous system, made up of the brain and spinal cord. 

NPCs respond to electrical stimulation by generating more cells, which can then migrate to areas in the central nervous system that need repair. This makes NPCs a valuable target following neural injury. 

Professor Morshead and her researchers’ biodegradable electrodes are part of a new and innovative method for neural repair, which the researchers are optimistic will aid in stroke recovery, as well as in repairing damage from other neurological disorders. 

The breakthrough

In their 2025 paper published in the scientific journal Biomaterials, the research team discussed the creation of the new device. The device is both precise and time-sensitive, but, best of all, it degrades in the body over the course of a week — an ideal timeframe validated by preclinical testing, which showed that the electrode activates NPCs and promotes neural growth without long-term complications. 

The electrodes are made from a conductive polymer containing molybdenum, a conductive element capable of transferring large electric charges into the brain with a current high enough to stimulate NPCs, but with less resistance to current flow. This feature reduces the risk of damaging sensitive brain tissue compared to other electrodes.

After this period, the electrode naturally biodegrades in the brain over the course of a few months, eliminating the need for surgical removal. While the idea of degradation inside the brain might sound uncomfortable, the process is painless and significantly reduces the risks linked to long-term implants, making it a safer and more convenient alternative to traditional neural repair strategies.

What’s next?

In recent years, scientists have been investigating non-invasive brain stimulation as a potential way to alleviate symptoms of various neurodegenerative disorders. Patients with conditions such as Alzheimer’s disease, depression, and Huntington’s disease have shown improvements with electrical brain stimulation. While the science behind neural repair is still developing, electrical stimulation has emerged as a promising path forward. 

In an interview with U of T News in January, Morshead said, “Our plan is to further develop this technology by creating multimodal, biodegradable electrodes that can deliver drugs and gene therapies to the injured brain.” 

Though the team is currently focused on improving stroke outcomes, they are hopeful that the technology could eventually be applied to other neurological disorders.