Sterilizing medical implants may be easier, more convenient, cheaper, and faster now that researchers have found a superior option: ozone gas.

Every year, millions of people in the United States go through inpatient surgery. In 2010 alone, 51.4 million surgical procedures were performed in the United States, of which 332,000 were hip replacements, 719,000 were knee replacements and 454,000 involved the insertion of a stent to the heart, according to the Centers for Disease Control and Prevention.

Many of these procedures will require implants such as pins and screws, which may now be made of polymer. The same material may also be utilized for tissue engineering, regeneration medicine and the delivery of drugs.

Indeed, polymer medical devices have gained popularity over the years because of their biocompatibility, more clearances from Food and Drug Administration and lower costs than other materials like ceramic or titanium.

But even then, polymer implants can be problematic for hospitals for many reasons.

"Maintaining sterile manufacturing facilities is extremely costly, so the ideal scenario is to sterilize the matrix post-manufacture," said Paul De Bank, pharmaceutics lecturer at the University of Bath in England.

However, the existing sterilization methods, which include radiation by electron beams, are challenging since they can potentially change the physical and chemical properties of the material. They also need additional training for the staff due to the complexity of the procedure, making these processes time-consuming and inconvenient.

The researchers from the University of Bath, in partnership with the University of São Paulo and the National Council of Technological and Scientific Development of Brazil, are currently recommending a more viable option: ozone gas.

Using ozone gas, produced by splitting oxygen to monoatomic molecules, for sterilization is not new. However, it had only been used to disinfect water and medical devices made of metal.

For the experiment, the team worked with nanofiber scaffolding made of specific polymer called poly(lactic-co-glycolic) acid (PLGA) and with Geobacillus stearothermophilus, a common biological indicator, to validate the sterilization process.

When the heat-resistant bacteria were exposed to pulsed ozone gas, they died. But the process didn't change any of the components of the scaffolding, and cells continued to grow as should happen.

Moreover, since the gas is just a by-product of oxygen in the atmosphere, it is cheaper to acquire and maintain. It is also convenient since it can be used to eliminate other types of pathogens like fungi and viruses.

The researchers believe that ozone gas can become a standard for sterilizing polymer implants. Not only that, "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," expressed De Bank.

The study is published in the journal Tissue Engineering Part C: Methods.

Photo: Austin Samaritans | Flickr

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