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Orthopedic device-related infections are a significant health issue that Vi-Khanh Truong, Ph.D., and colleagues at Flinders University in Australia want to solve with a new implant coating that has antibacterial properties and stimulates bone growth.
The now-patented coating material consists of novel silver/gallium nano-amalgamated particles that significantly reduce the incidence of post-op infections, according to a recent study Dr. Truong co-authored in the journal Advanced Functional Materials.
The study showed that the technology promotes osteointegration, which is crucial for the success of joint replacement surgeries. It also demonstrated that the coating material can be easily applied to medical devices through spray-casting, a development that brings the technology one step closer to commercialization.
“Our latest testing indicates this combination of antibacterial protection and tissue integration properties can benefit many devices in the orthopedic and trauma areas,” said study senior author Krasimir Vasilev, Ph.D., Director of the Biomedical Nanoengineering Laboratory at the College of Medicine and Public Health at Flinders University.
“This is a significant advance compared to current materials and technologies available to surgeons and patients,” Dr. Truong added.
Solving a Stubborn Problem
One of the primary challenges in joint replacement surgery is the risk of postoperative infections, which can lead to severe complications that require additional surgeries and prolonged antibiotic treatment. In rare cases, complications can lead to limb amputation and even patient death. The total cost to treat an infection can exceed $100,000.
Current orthopedic device-related infection rates remain between 2% and 10%, despite the use of stringent infection prevention protocols and sterile surgical fields, according to the Advanced Functional Materials study. When infections occur, traditional antibiotic therapies are limited in efficacy and infections can reoccur after treatment.
“The high incidence of such infections poses immense challenges to medical professionals and patients, and adds enormous costs to healthcare systems,” Dr. Truong said. “Our team recognized the urgent need for breakthrough solutions to reduce infection rates that have been stubbornly stagnant for a long time.”
The antibacterial capabilities of compounds derived from silver have been extensively researched, but the element comes with inherent drawbacks.
“Silver ions, while known for their potent antibacterial properties, present cytotoxicity issues, which limit their use in medical applications,” Dr. Truong said. “We aimed to develop a material that harnesses the antibacterial capabilities of silver without its adverse effects. Our new formula ensures the sustained release of silver and gallium ions in a very controlled manner to eliminate these issues.”
In many applications, the toxicity associated with silver ions is due to their high concentration levels. The new coating’s nano-amalgamation ensures a controlled and sustained release of silver ions. By controlling the release rate, the formula ensures that the silver ions are present in quantities sufficient for antibacterial action, but below the threshold that would cause cytotoxic effects to human cells.
Gallium ions in the nano-amalgamation also play a crucial role.
Dr. Truong said that gallium ions are known for their role in bone formation and regeneration. They can stimulate osteoblast activity (the cells responsible for bone formation) and suppress osteoclast activity (the cells responsible for bone resorption). The controlled release of gallium ions and their anti-inflammatory properties directly contribute to bone growth and healing.
“The combination of silver and gallium in the nano-amalgamation reduces the required amount of silver, thereby lowering the risk of cytotoxicity while maintaining antibacterial efficacy. It also provides synergistic effects that are beneficial for bone growth,” Dr. Truong said. “While silver provides antimicrobial properties, gallium contributes to bone formation and reduced inflammation, collectively creating an environment conducive to bone growth and healing.”
He was surprised by the successful amalgamation of silver and gallium at the nano-scale level and its efficacy in addressing infection prevention and promoting bone growth. “Combining these two distinct functionalities in one coating is a significant achievement,” he said. “It creates the potential for the coating to be applied to various types of medical devices, not just orthopedic implants.”
Eyeing Future Opportunities
The coating’s formulation might need to be refined during extensive preclinical studies before human trials are conducted, according to Dr. Truong. “This could involve optimizing the controlled release of ions, enhancing the coating’s durability and ensuring its efficacy across a range of conditions,” he said. “Ongoing assessment of the long-term biocompatibility and potential toxicity of the coating in biological systems is crucial.”
Dr. Truong said the implant coating has the potential to apply to various implantable devices, catheters and other access devices, and even wound dressings where infections are also problematic.
Gaining regulatory approval from FDA or EMA will involve submitting detailed data that demonstrate the coating’s safety and efficacy, Dr. Truong noted. He also said that establishing partnerships with medical device companies and healthcare providers will be crucial for the market adoption of the coating.
“We have patented this new promising technology, which places us in a very good position to move to commercialization with a spin-out company, partnering with existing device manufacturers — or both,” Dr. Truong said. “Commercialization opportunities could make this solution available to clinicians and patients at a time when growing antibiotic resistance is yet another problem in global healthcare.”
