Plastic fantastic for bug killing film

Scientists in Switzerland say they have created a plastic film that’s up to 1000 times more effective at killing E. coli bacteria than conventional methods.

The new film gives Ecoli the silver service

The team from the Swiss Federal Institute of Technology in Zurich have discovered that coating the film with a mix of silver and calcium phosphate nano-particles proves deadly to bacteria.

Wendelin Stark, the leader of the project, explained it had been previously impossible to apply silver in a targeted and measured way. However, by using a film and applying the silver to the calcium phosphate, he believes the problem has been overcome.

“Within 24 hours of the plastic film being applied to a surface, less than 1 bacterium out of 1 million bacteria will survive,” He said.

Because bacteria rely on calcium for their metabolism, the calcium phosphate particles are used by the microorganisms as nutrition. When the bacteria consume the calcium phosphate thousands of silver particles - only 1-2nm in diameter - are released. It is these tiny silver particles that kill the bacteria and prevent germs from growing and spreading.

The polymer film only emits silver if bacteria are growing in the vicinity. This can be assessed by the quantity of calcium phosphate that is taken up by the bacterium.

“It saves money and is much more efficient,” said Stark. “It also reduces the environmental impact of the process and we have developed a method that is easy to apply and could bring great benefits to patients in hospitals, as well as the food industry.”

The work has been praised by Dr David Brown, Chief Executive of the Institution of Chemical Engineers: “This is an outstanding example of how chemical engineers are making a crucial contribution to society”.

Silver was also used in medical treatments before being replaced by antibiotics but nanotechnology has allowed the metal something of a medical renaissance. The project is now being up scaled by a Swiss Company.