Ozone Effective for Sterilizing Medical Implants

A new study demonstrates how ozone (O3) can be effectively used to sterilize poly(lactic-co-glycolic acid) (PLGA) nanofibers, one of the most common polymers used in implants.

Researchers at the University of São Paulo (USP; Brazil), the University of Bath (United Kingdom), and other institutions conducted a study to investigate pulsed O3 gas as an alternative method for sterilizing electrospun PLGA nanofibers. To do so, they assessed the morphology, mechanical properties, physicochemical properties, and response of cells to PLGA nanofiber scaffolds following different degrees of O3 gas sterilization.

They found that the treatment effectively killed Geobacillus stearothermophilus spores, the most common biological indicator used for validation of sterilization processes. In addition, the O3 gas sterilization method preserved all of the characteristics of nonsterilized PLGA nanofibers at all degrees of sterilization tested. In contrast, other methods, such as gamma beam, electron beam, and autoclave sterilization can damage the polymer, due to the heat, pressure, and toxicity involved.

“Sterility is a critical attribute of implantable materials that needs to be met in order to be applied in vivo,” concluded lead author PhD student Carolina Rediguieri, MSc, of USP. “Our findings suggest that sterilization by ozone gas is very likely to work for other implantable polymers as well, especially other polyesters.”

“Polymer implants, such as screws, pins and stents, are commonly used in surgical treatments, and there is an increasing use of implantable polymers in fields such as drug delivery, regenerative medicine and tissue engineering,” added senior author Paul De Bank, PhD, of the department of pharmaceutics at the University of Bath. “Maintaining sterile manufacturing facilities is extremely costly, so the ideal scenario is to sterilize the matrix post-manufacture. Unfortunately, many sterilization techniques adversely affect the physical or chemical properties of the materials used in the scaffolds, and this can alter their overall performance.”

Ozone is a pale blue gas with a distinctively pungent smell reminiscent of chlorine. It is an allotrope of oxygen, formed from dioxygen (O2) by the action of ultraviolet light as well as atmospheric electrical discharges, and is present in low concentrations throughout the stratosphere. Ozone is a powerful oxidant and has many industrial and consumer applications. Many hospitals around the world use large ozone generators to decontaminate operating rooms between surgeries.

Related Links:
University of São Paulo
University of Bath