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Antimicrobial plastics play role in disease prevention

By: Jeremy Carroll

September 13, 2013

GURNEE, ILL. — As the health-care industry grapples with the best ways to stop the spread of infectious diseases within hospitals, the plastics industry may be an important ally in the fight.

One potential weapon: antimicrobial plastics.

Plastic surfaces, those touched by patients and doctors regularly, could have built in resistance to bacteria and other disease.

"Not a whole lot of inherently antimicrobial plastics have been adopted so far [for touch surfaces]," said Manish Nandi, senior product developer for Sabic Innovative Plastics.

Nandi spoke about hospital acquired infectious diseases, and how plastics can play in a role in the prevention and spread of diseases at the Society of Plastic Engineers Medical Plastics MiniTec, held Sept. 9 in Gurnee.

The antimicrobial plastics won't be the cure-all, he said.

"The primary control is still going to be cleaning," Nandi said. "What the inherently antimicrobial plastics are going to give you is some sort of insurance policy. If you miss a spot, then you have a material that is self, sort of, killing the bacteria."

While each hospital has a cleaning protocol, the system is a human effort and not uniform.

"It's not the same from hospital to hospital," he said. "So there is something that may be missing from a cleaning protocol."

Those potential missed spots are where the antimicrobial plastics could play a part. It could also play a part while the patient is still in the room.

"The room only gets cleaned when the patient leaves, they don't spray down the room on top of a patient," Nandi said. "So having an insurance policy in place while the patient is there won't be bad."

There are different types of inherently antimicrobial plastics including those that would repeal the bacteria or those that would kill the bacteria, he said.

In addition to inherently antimicrobial plastics, Nandi said developing plastics that hold up color and structure to chemical cleaners also is a difficult task.

"The cleaners, they are good inventors," he said. "And so to kill these really resistant bugs, they are coming up with harsher and harsher chemicals. And that is putting pressure on folks like us who are making the materials and surfaces because these materials are not friendly to the harsher chemicals."

So Sabic has started a study to look at different polymers with different cleaners to see how they react. And what might be the best solution for surfaces that come into constant contact with patients.

"It's an ongoing study, so we don't have any results right now, but we hope to have something by the end of the year," he said.

Other items can be sterilized in a number of ways: gamma rays; ethylene oxide; autoclaving; or low-temperature hydrogen peroxide gas. All have advantages and disadvantages, and various plastics hold up in different ways to each — polycarbonates will discolor with gamma rays, for instance — he said.

Nandi said a polyetherimide resin has proven to hold up to all different types of sterilization.

"The claim to fame for this material is it is resistant to all four sterilization types, which is a very big advantage for the device designer," he said. "You have a universal choice."