Sterilizing implants with oxygen may save time, money

The risk for implants to be damaged during sterilization is far lower when using oxygen, researchers say.

By Stephen Feller

BATH, England, April 29 (UPI) -- Polymer implants such as screws, pins and stents need to be sterilized before being used in surgical procedures, but standard methods have the potential to damage them -- leading researchers to find a sterilization method they say is far superior in every way.

Ozone gas, made by passing electricity through oxygen, was shown in a recent study, published in the journal Tissue Engineering: Part C, to not damage the physical or chemical properties of implants.


Standard methods of sterilization such as gamma or electron beam radiation are expensive and damage the implants, made of polylactic-co-glycolic acid, or PLGA. They also are more expensive and require special training for medical staff. Ozone, on the other hand, is a byproduct of atmospheric oxygen, and is cheap and safe.

"Sterility is a critical attribute of implantable materials that needs to be met in order to be applied in vivo," Carolina Rediguieri, a doctoral student at the University of Bath, said in a press release. "Our findings suggest that sterilisation by ozone gas is very likely to work for other implantable polymers as well, especially other polyesters."


For the study, researchers tested the efficacy of pulsed ozone gas to sterilize PLGA nanofiber scaffolds, which are increasingly being used for drug delivery and tissue engineering.

The researchers found geobacillus stearothermophilus spores, a common biological indicator for sterilization, died when exposed to the ozone treatment, and the scaffolds were not affected when exposed to ozone pulses.

With increased use of PLGA polymers for implants and other medical tools, all of which must be sterilized, the researchers think ozone gas could become a standard for preventing infection while also protecting the shape and makeup of implants.

"Maintaining sterile manufacturing facilities is extremely costly, so the ideal scenario is to sterilize the matrix post-manufacture," said Dr. Paul De Bank, a professor of pharmaceutics at the University of Bath, adding, "the fact that ozone performed so well suggests it could be routinely used to sterilize not only PLGA, but a wide range of materials used in clinical implants."

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