Ethylene oxide “gas” sterilisation
- Mode of action: microbicidal activity results from the alkylation of protein, DNA, and RNA. Alkylation, or the replacement of a hydrogen atom with an alkyl group, within cells prevents normal cellular metabolism and replication.
- The main disadvantages associated with ETO are the lengthy cycle time, the cost, and its potential hazards to patients and staff; the main advantage is that it can sterilise heat or moisture-sensitive medical equipment without deleterious effects on the material used in medical devices.
Hydrogen peroxide gas plasma
- Gas plasmas are generated in an enclosed chamber under deep vacuum using radio frequency or microwave energy to excite the gas molecules and produce charged particles, many of which are in the form of free radicals.
- Free radicals within a plasma field are capable of interacting with essential cell components (e.g. enzymes, nucleic acids) and thereby disrupt the metabolism of microorganisms.
- Uses: materials and devices that cannot tolerate high temperatures and humidity, such as some plastics, electrical devices, and corrosion-susceptible metal alloys.7