Villanova and Pulse Technologies innovate antimicrobial coating for implantable devices

Implantable neurostimulation devices assist patients in managing neurological and chronic conditions by delivering targeted electrical stimulation to influence nerve function. However, implant contamination can occur during or after surgery, leading to infections and severe health complications. To address this issue, Pulse Technologies, Inc. (Quakertown, PA), a leader in medical device manufacturing, partnered with Villanova University to develop an antimicrobial surface coating for implantable electrodes to reduce the risk of device-related infections.

Implantable neurostimulation devices are a special class of medical devices implanted under the skin, offering a minimally invasive way to manage symptoms and improve a patient's quality of life. Implanted devices have electrodes that sense signals from the body and stimulate the nervous system. These neural-interfacing devices are commonly used to treat a range of neurological disorders, including Parkinson's disease and epilepsy, and they also assist in pain management.

For safe, long-term application of implants, it is essential to incorporate antimicrobial properties to resist microbial-induced infection. Currently, most implantable electrode devices lack antibacterial properties, resulting in unmet specialized needs within the medical device manufacturing market.

“There is growing demand for manufacturing devices and components that can kill bacteria in situ, from within the body,” says Shahram Amini, director of R&D at Pulse. “Antibiotic resistance is a global threat because, over time, the body becomes less responsive to antibiotics.”

As bacteria mutate, new strains emerge, requiring the development of new antibiotics to treat each type of infection effectively. Amini explains that the demand arises from a desire within the medical community to combat antibiotic resistance by reducing the reliance on creating new antibiotics for every infection. Instead of giving patients antibiotics to kill bacteria resulting from surgery, the implanted device can fight the infection itself. Patients may even recover faster by eliminating barriers to wellness, such as the need for antibiotic prescription compliance.

Gang Feng, associate professor of mechanical engineering at Villanova, says that the intent of the coating technology is twofold: to provide a protective barrier on the device before implantation and to actively prevent the formation of harmful microbial clusters on the medical devices after implantation. Once implanted, the coated device can generate a local environment that, while safe for humans, releases an antibacterial substance that can kill bacteria or minimize the possibility of post-surgery infection.

This problem [of implant-device-induced infections] raises an opportunity to bring together industry and academia to investigate solutions. Many facets of expertise and knowledge are needed to solve difficult problems like these, and we certainly benefitted from the complementary collaboration on this project.

Gang Feng, associate professor of mechanical engineering, Villanova University

To impart antibacterial properties to the electrodes, Feng explains that a uniform and relatively thin antibacterial coating must be applied to their hierarchical surfaces to maintain high performance.

“The technique we used is called atomic layer deposition, which produces a very thin and uniform coating,” Feng states. “This is the expertise the Villanova team brought to the project.”

Typically, antibacterial materials are incompatible with electrodes. Moreover, electrodes themselves lack antibacterial properties. According to Feng, the project's challenge was integrating these elements using Pulse’s proprietary laser technology. The research team demonstrated that by combining the two technologies into a single platform, they could manufacture multifunctional electrodes for medical devices that enhance device performance while also providing antibacterial properties.

Feng and Amini believe that this technique, which uses Pulse’s higher-performance electrodes,  can have a broad impact on the larger medical device community. Having achieved proof of concept, their initial findings were published in Scientific Reports, a Nature journal.

“We’ve had very promising results and are working to continuously improve upon the performance of these electrodes and the types of materials that potentially can be applied onto surfaces,” says Amini. “The work is ongoing.”