This is the claim from a team at Washington State University whose work is detailed in the International Journal of Extreme Manufacturing
The team’s work could lead to better infection control in many common surgeries such as hip and knee replacements. Bacterial colonisation of the implants is one of the leading causes of their failure and unsatisfactory outcomes after surgery.
In a statement, Amit Bandyopadhyay, corresponding author on the paper and Boeing Distinguished Professor in WSU’s School of Mechanical and Materials Engineering, said: “Infection is a problem for which we do not have a solution. In most cases, the implant has no defensive power from the infection.
“We need to find something where the device material itself offers some inherent resistance - more than just providing drug-based infection control. Here we’re saying, why not change the material itself and have inherent antibacterial response from the material?”
Titanium materials used for hip and knee replacements and other surgical implants were developed over 50 years ago and are not well suited to overcoming infections. Although surgeons often treat pre-emptively with antibiotics, life-threatening infection can occur following surgery, or weeks or months later as a secondary infection.
Doctors try to treat infected implants with systemic antibiotics, but in around seven per cent of implant surgery cases, doctors must perform a revision surgery where they remove the implant, clean the area, add antibiotics and replace the implant.
Using 3D-printing, the WSU researchers added 10 per cent tantalum, a corrosion-resistant metal, and three per cent copper to the titanium alloy typically used in implants.
When bacteria encounter the material’s copper surface, almost all of their cell walls rupture. Meanwhile, the tantalum encourages healthy cell growth with surrounding bone and tissue.
According to WSU, the researchers spent three years on a comprehensive study of their implant, assessing its mechanical properties, biology and antibacterial response in the lab and in animal models. They also studied its wear to make sure that metal ions from the implant will not wear off and move into nearby tissue causing toxicity.
“The biggest advantage for this type of multifunctional device is that one can use it for infection control as well as for good bone tissue integration,” said co-author Susmita Bose, Westinghouse Distinguished Professor in the school. “Because infection is such a big issue in today’s surgical world, if any multifunctional device can do both things, [then] there’s nothing like it.”
The researchers are continuing the work, hoping to improve the bacterial death rate to the standard of more than 99 per cent without compromising tissue integration. They also want to make sure that the materials offer good performance under real-world loading conditions that patients might use.
The researchers are working with WSU’s Office of Commercialization and have filed a provisional patent. The work was funded by the US National Institutes of Health and included collaboration with researchers from Stanford University and WSU’s College of Veterinary Medicine.
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