Implant infection protection twofolded

A new hybrid implant coating composed of antibacterial silver and an antibiotic will prevent infection in implanted patients. The antibiotic fits the patient’s unique requirements for enhanced protection.

An artificial knee, shoulder, or hip joint at the hospital brings the expectation of the best possible treatment and high-end medicine. But implantation has its risks. Approximately, 1 to 2 percent of all patients will develop an infection following the operation. If the discomfort level is drastic and it requires a second surgery, an infection can be expected with a ¼  ratio. 1. Even if the individual risk is low, it affects the surgery frequency affects the patients.

 In view of demographic developments, prosthesis operations numbers will also increase steadily. In the case of antibiotics, the administration remains unhelpful, it could be a long and painful process. And in the worst case, the implant will have to be replaced.

Hybrid coating

This new approach promises to significantly reduce the risk of infection. A hybrid coating consisting of antibacterial silver and an antibiotic that fits the patient’s requirements or more precisely to the bacteria is applied to the implant. The idea was developed four years ago at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen.

Kai Borcherding, Head of Medical Technology and Life Sciences at Fraunhofer IFAM, states: “Surface treatment is one of the areas our institute specializes in. Applying this expertise to medicine was a natural choice.”

Fraunhofer researchers developed, tested, and implemented this in the AntiSelectInfekt Project, cooperating with researchers of the Julius Wolff Institute and the BIH Center for Regenerative Therapies (BCRT) of Charité in Berlin.

The results are bright. “The preclinical studies have demonstrated that the hybrid implant coating effectively reduces the rate of infection,” explains Prof. Britt Wildemann. Prof. Wildemann conducts the studies on effectiveness and biocompatibility in Berlin and is now Head of Experimental Trauma Surgery at Jena University Hospital.

Old Idea, New Invention

Coating implants is not a new idea. The ability of silver and antibiotics in fighting infections related to implants has been studied for a long time. The new thing is the approach of combining the two and thus improving the active protection.

The benefits are not over. Researchers have developed a process allowing them to use an antibiotic fitted to the patient’s requirements. The special coating technology developed by Fraunhofer IFAM also regulates the release of the antimicrobial substances: while the antibiotic is released in full once the implant is in place, the silver particles take effect gradually close to the surface over a longer period of time, hence providing durable protection that keeps on to healing phase.

Laser coating technology: A Bremen Production

The coating process is based on tried-and-true technologies developed especially for the project.

The first stage is to apply a structure to the titanium implant surface using a laser. This creates a porous layer,” explains Borcherding. Tiny invisible pores of mere micrometers in size appear on the titanium surface.

These pores are amphora-shaped. In the second stage, researchers use the process of physical vapor deposition for applying a layer that contains silver particles.

During the surgery, these amphora-shaped pores can be filled. Before implantation application, the surgeon immerses the sterile silver coating implant in a solution containing the antibiotic.