Keeping bacteria out of implants without antibiotics
Professor Michael Gasik participated in the development of implant materials that reduce the risk of infection by up to 95 percent compared to a traditional surface material.
You might think that today's patients do not have to worry about infections due to modern hospitals, good hygiene and professional staff. You thought wrong.
‘The human body is never sterile’, says Professor Michael Gasik from the Department of Materials Science and Engineering. ‘Before an operation, we cannot know exactly what kinds of bacteria will be found within the person's body, within vicinity of the implant and which bacteria will turn up the operation.’
Race for living space
Patients are traditionally being treated with strong antibiotics to avoid post-operative complications due to infections, but approximately 10-15% of complications are still caused by antibiotics-resistant bacteria. Usually the biofilm formed by bacteria significantly weakens the effectiveness of antibiotics (even by 100 000 times) and thus prevents the proper treatment of infections. A solution to this problem may be available outside medicine. Professor Gasik and his research group participated in an EU project for developing safer implant materials.
‘Our focus was on the coating of materials and the interaction between the coated material, bacteria and cells’, Michael Gasik explains.
A titanium implant material using the optimised coating and technology developed in the project can reduce the risk of a bacterial infection by up to 65-95% compared to ordinary, porous titanium implants, even when no antibiotics are used.
‘The surface structure plays an important role’, Professor Gasik emphasises. ‘When an implant is placed in a human body, a "race for space" for living begins between cells and bacteria. Our task is to design the surface so that the cells win the battle and can quickly attach to the implant forming pre-tissue structure. This also weakens the bacteria's ability to form a biofilm, even some bacteria still manage to attach to the surface.’
Millions of implants every year
In addition to surface optimisation, the project resulted in a new, titanium-based material. The material does not contain any aluminium or vanadium which could elute and cause negative reactions: in the worst-case scenario, an elevated risk of cancer.
‘The U.S. Food and Drug Administration (FDA), for instance, does not recommend metal implants for patients with renal insufficiency, patients with HIV and immune system disturbances, young and fertile women or hypersensitive people’, Michael Gasik points out. "In the UK, several medical device alerts have been issued to put stricter monitoring on metal ions concentration in the blood."
The results of the project would have global significance, since millions of patients undergo some form of implant surgery every year. The European Commission selected the project as one of the most promising projects in the Sixth EU Framework Programme for Research and Technological Development (FP6) and the commercialisation of the developed technology is already under way. One of the continuation projects is the Tekes TUTL project whose participants include Aalto University, international companies, Oulu University Hospital and the Finnish Red Cross Blood Service.
‘One of the objectives of the continuation project is to develop a new method and device for the in vitro testing of biomaterials in order to improve the reliability and safety of materials’, Michael Gasik explains.
The test conditions have been designed to be as similar to the human body as possible.
‘The test conditions have been designed to be as similar to the human body as possible, which improves the reliability of the results, accelerates the development of biomaterials and reduces the need to use animal testing. It also creates opportunities for designing new materials, including materials containing a patient's own stem cells or new medicinal substances’, Gasik adds.
Professor (Full Professor)
Materials Processing and Powder Metallurgy
michael.gasik [at] aalto [dot] fi