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Bacteria insight to improve implants

Date posted: Tuesday 9 Mar 2010

Researchers from Swinburne University of Technology have made a discovery that could go a long way to improving the success rates of artificial implants and reduce the risk of bacterial outbreaks in hospitals.  

In a paper published in Langmuir, the journal of the American Chemical Society, the researchers debunked a common theory about the way bacteria adhere to surfaces.

Up until now scientists believed that bacteria attach more easily to rough surfaces, based on the theory that microscopic valleys provide shelter from disinfection processes. Some implant manufacturers have even made their products ‘nano-smooth’ to prevent bacteria from finding protection from the sterilisation process.

However, using nano-smooth titanium and microbiological analysis techniques, the Swinburne team, including microbiologist Professor Elena Ivanova and surface chemist Professor Russell Crawford, disproved this theory.

According to Crawford, the researchers were able to show smooth surfaces are actually more attractive to some problematic bacteria, meaning a higher degree of bacterial colonisation on smooth surfaces than on rough. 

“The way bacteria attach to nanosmooth surfaces is different to the way they adhere to rough surfaces,” said Crawford. “The bacteria adhere to these surfaces by secreting a substance containing sugars and proteins – making it easier for the bacteria to attach to the surface. This is the first time that it has been shown that this ‘sticky’ substance is produced in much greater quantities when bacteria come into contact with nanosmooth surfaces, causing a greater amount of bacterial attachment.”

The discovery has significant implications for one of the most troublesome issues of modern medicine, infection-related implant failures.  

According to Ivanova, up to 67 per cent of implants are troubled by bacterial problems. Despite thorough sterilisation processes, this high percentage of medical implants, commonly hips and knees, fail because some types of bacteria attach to the implant as a biofilm, causing infection.

The Swinburne research suggests that hospitals may have to rethink their disinfection techniques and that implant manufacturers may have to develop new disinfectants and review their production methods.

The scientists’ work is still in the early stages. “We are really looking at what causes biofilms to form and how well they form on a range of different surfaces. Eventually we hope our findings will be used by companies to produce more effective disinfection processes and surface coatings,” Crawford said.

The Swinburne team, working with specialists from Monash University, combines the skills of scientists from numerous specialisations – microbiology, nanotechnology, engineering and industrial sciences.

Read more about this research in the latest edition of the Swinburne magazine.