Biodegradable Electrodes Repair Damaged Brain Tissue Without Need for Surgical Removal

Neurological disorders often lead to irreversible cell loss and are a major cause of disability worldwide, with limited treatment options available. A promising therapeutic approach is the stimulation of neural precursor cells (NPCs) — rare cells that have the potential to repair neural tissue. While previous techniques, such as transcranial direct current stimulation, have shown promise, they lack the precision needed and can cause tissue damage. Now, newly developed electrodes address these issues by offering precise, safe, and temporary stimulation, eliminating the need for follow-up surgical procedures.

Researchers at the Faculty of Applied Science & Engineering at the University of Toronto (Ontario, Canada) have created a flexible, biodegradable electrode designed to stimulate NPCs in the brain. This device provides targeted electrical stimulation for up to seven days before naturally dissolving, eliminating the need for surgical removal. By tapping into the body’s natural repair processes, this innovation marks significant progress in the treatment of neurological disorders. In designing the biodegradable neural probe, the team focused on selecting materials that would offer both biocompatibility and adjustable degradation rates. Poly(lactic-co-glycolic) acid (PLGA), a flexible and FDA-approved material, was chosen for the substrate and insulation layer due to its predictable degradation based on monomer ratios and its minimal inflammatory response.

Image: Design and fabrication of biodegradable electrode for brain stimulation (Photo courtesy of Biomaterials, DOI:10.1016/j.biomaterials.2024.122957)

Molybdenum was selected for the electrode itself, as it is durable and dissolves slowly—two essential properties that ensure the electrode maintains its structural integrity during the intended one-week stimulation period. In research published in Biomaterials, the electrodes were implanted into animal models, where they successfully stimulated NPCs, boosting both their numbers and activity without causing significant tissue damage or inflammation. This testing confirmed the electrodes' safety and efficacy for stimulating neural repair within the targeted time frame.

“Our plan is to further develop this technology by creating multimodal, biodegradable electrodes that can deliver drugs and gene therapies to the injured brain,” said Professor Cindi Morshead, one of the researchers who led the study. “We have exciting data to show that activating brain stem cells with our electrical stimulation devices improves functional outcomes in a preclinical model of stroke.”