Fighting bacteria with nanostructures – Titanium implant surfaces given bactericidal properties in the Nano Argovia project TiSpikesSNI INSight May 2020
In the Nano Argovia project TiSpikes, an interdisciplinary team is investigating how a nanostructure can deter bacterial growth and the formation of biofilms on titanium implants. Researchers from the University of Basel’s Department of Physics and Department of Dental Medicine are working closely with the School of Life Sciences (FHNW) and Institut Straumann AG (Basel). Dr. Laurent Marot and Dr. Khaled Mukaddam (both from the University of Basel) lead the project.
Avoiding biofilm formation
Bacteria are everywhere – including in and on the human body. Most of them are beneficial, but in some cases they can cause serious problems – for example on implants, when bacteria adhere to them and form thin layers known as biofilms. This causes infections that can ultimately lead to the loss of the implant.
Bacterial growth can be suppressed to some extent by antibiotics. However, more and more bacteria are acquiring resistance to antibiotics. Once a biofilm has formed, even powerful antibiotics are often of no use as only the outer layer of bacteria comes into contact with them. It is therefore desirable to find a solution that prevents bacteria from colonizing the implant in the first place.
Learning from nature
Nature offers multiple examples of surfaces that remain sterile with no need for antibiotics. The wing surface of cicadas, for example, is covered in minute pillars, while the skin of a gecko is equipped with nanostructures that stop biofilms from forming on it. It makes sense to structure the surface of implants in such a way that bacteria cannot grow on them and form biofilms.
The focus of the TiSpikes Nano Argovia project is on surfaces made from titanium and titanium alloys already used in implants. The University of Basel’s Department of Physics has developed a process that can be used to structure the surface of these alloys in a variety of ways.
The researchers are now testing which structures are most effective at thwarting bacteria of different sizes. This is achieved by recourse to different microscopic methods, including scanning probe microscopy to determine the adhesive forces in place between the bacteria and the various surfaces.
Suitable foundation for tissue cells
Yet, the ideal nanostructure – particularly when it comes to dental implants – is not just one that prevents bacterial growth, but one that promotes adhesion of the surrounding tissue cells. The researchers anticipate that this will help minimize bacterial colonization in the space between implant and tissue, thereby preventing infections.
“We are very excited about this project, which will bring together partners with very different areas of expertise. We aim to test the structured implant surfaces in vivo for preclinical assessment with the clear goal of providing our customers with the best possible solutions.”
Dr. Raphael Wagner, Head of Surfaces Research, Institut Straumann AG