Researchers at the Faculty of Applied Science & Engineering at the University of Toronto have developed a flexible, biodegradable electrode capable of stimulating neural precursor cells (NPCs) in the brain. This device delivers targeted electrical stimulation for up to seven days before dissolving naturally, eliminating the need for surgical removal.
By harnessing the body’s innate repair mechanisms, this innovation offers a step forward in treating neurological disorders, which are a leading cause of disability worldwide. The work, led by Professors Hani Naguib (MSE, MIE) and Cindi Morshead, who is from the Temerty Faculty of Medicine’s Department of Surgery and cross-appointed to the Institute of Biomedical Engineering, was published in a recent issue of Biomaterials.
Neurological disorders often result in irreversible cell loss, with limited treatment options available. A promising therapeutic approach involves stimulating NPCs — rare cells capable of repairing neural tissue. While previous methods, such as transcranial direct current stimulation, have shown promise, they lack precision and can damage tissue.
The newly developed electrode addresses these challenges by providing precise, safe and temporary stimulation without requiring subsequent surgical interventions.
“Neural precursor cells hold significant potential for repairing damaged brain tissue, but existing methods for activating these cells can be invasive or imprecise,” says Morshead.
“Our biodegradable electrode provides a solution by combining effective stimulation with reduced patient risk.”
To design the biodegradable neural probe, the team focused on materials that provided both biocompatibility and tunable 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 minimal inflammatory effects.
Molybdenum was selected for the electrode itself, due to its durability and slow dissolution, both qualities essential for maintaining structural integrity during the intended one-week stimulation period.
The electrodes were implanted in animal models and demonstrated the ability to stimulate NPCs effectively, increasing their numbers and activity without causing significant tissue damage or inflammation. This testing ensured the electrodes’ safety and efficacy for neural repair stimulation within the targeted time frame.
“Our findings demonstrate that this electrode can stimulate neural repair in a controlled, temporary manner, which is crucial for avoiding complications associated with permanent implants,” says Tianhao Chen, a BME PhD student and the lead author of the study.
“Our plan is to further develop this technology by creating multimodal, biodegradable electrodes that can deliver drugs and gene therapies to the injured brain,” says Morshead.
“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.”
