Inactivation of endotoxin by low-pressure plasma

Endotoxin (ET) is known as the most powerful pyrogen in nature. ET induces ague, fever, or a shock state in humans, causes bacillemia or sepsis in severe cases, and can be fatal. Therefore, devising a method to produce ET-free products presents a significant challenge to control the quality of medical products.The two broad classes of depyrogenation method that may be applied to components and devices are inactivation and removal.However, it is difficult to inactivate ET in a dry state. ET is highly heat-stable and, hence, is not destroyed under regular heat sterilization procedures, dry-heat treatment for 30 min at 250°C, is essential. Namely, a practical method to obtain ET-free products has yet to be established. Plasma is used by the semiconductor industry to remove organic polymers such as photo resist from delicate electronic components. Currently, research on applied plasma technology has been extended to the microbiological fields, including sterilization and disinfection. Further, there are trends toward using low-pressure plasma to inactivate ET. Some study results have been reported, in which gas plasma discharge showed practical effectiveness in the inactivation of ET at a low temperature on short-term exposure non-toxic gas. In the future, for effective use of plasma technology, a multi-step process may be necessary, since the optimum conditions are different for sterilization and decontamination. This will contribute to methods for the inactivation of ET contaminating surgical products and medical implants.