New professor aims to kill bacteria on orthopaedic implants with tiny knives

1 May 2020• NEWSITEM

Infections of orthopaedic implants are hard to treat with antibiotics. Therefore, Professor Amir Zadpoor works on alternative ways to prevent and treat implant-associated infections. As of May 1st 2020, Zadpoor has been appointed professor of Orthopaedics, in particular orthopaedic implants, in Leiden.

Zadpoor is already professor at TU Delft and has been collaborating with the LUMC for almost 10 years now. “Over the years, there has been a natural fusion of my activities in Delft and the research at the Orthopaedics Department of the LUMC, now we just formalized it.” 

Alternative for antibiotics 

Zadpoor’s research within the LUMC’s Orthopaedics Department will focus on developing new implants and replacing the use of antibiotics for the treatment of implant-associated infections. 

“Like any other ‘foreign’ object to the human body, one huge problem of orthopaedic implants is that they make infections easier to occur and more difficult to treat.” Bacteria that found their way to the implant will form a protective layer, a biofilm. Due to this layer, antibiotics cannot easily reach the bacteria. One solution would be to increase the dose of antibiotics, but since you would need up to a 1000 times higher concentrations, this is not an option. Zadpoor is working on alternative ways to kill bacteria on implants. “We developed a nanopattern that covers the implant. This pattern consists of many very small knife tips which physically kill bacteria. It looks pretty brutal under the microscope.”       

Origami

However, this nanopattern can only be applied on a flat surface and not on a bone-shaped implant. Therefore, Zadpoor and his team are working together with the LUMC to use 4D printing. “It is actually very simple”, Zadpoor explains, “you 3D-print a flat object, then apply the nanopattern and teach this object to change its shape upon a stimulus, such as light or temperature, into a 3D implant, just like origami.” 

Patient-specific implants

Besides infections, patients can encounter mechanical problems with their implants. Therefore, Zadpoor is working together with the Orthopaedics Department to develop patient-specific 3D-printed implants, which match the patient’s anatomy better and could, therefore, last longer. This will be applied to, for example, cancer patients who lost a big piece of bone due to a bone tumour. “Usually they do not have that much bone left to anchor the implant. In addition, the risk of infections is even higher in those patients since their immune system is often compromised. Therefore, implant loosening usually happens earlier. By developing patient-specific implants, implant longevity could greatly improve.”   

Corona crisis

Currently, Zadpoor and his team, together with clinicians of the LUMC, are developing a ventilator that can be assembled from cheap and local parts. The design will be shared with the rest of the world in order to fight the shortages of ventilators during the corona crisis.  

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