Ethylene oxide (EtO) is a suspected human carcinogen. EtO exposure is associated with an increased risk of miscarriages. Large doses can cause vomiting, cyanosis and pulmonary edema. EtO mixtures can displace oxygen and lead to asphyxiation.
EtO is usually diluted with some other gas (carbon dioxide or flurocarbons) so it can't form explosive mixtures with air.
EtO mixtures are usually humidified to make them more effective.
The first step in most EtO cycles involves drawing vacuum.
EtO is absorbed by paper and plastic. Items must be aerated after sterilization to remove residual EtO.
EtO attacks some adhesives.
EtO works by alkylating biomolecules like DNA and enzymes.
Packaging must be gas permeable.
Heat can deform some medical plastics
Moisture can effect some products.
Moist heat generally works by denaturation of enzymes and hydrolysis of DNA and RNA.
Packages must be gas permeable.
Common autoclaves use steam sterilization.
Most systems operate at 121C (15 psig).
Often used to sterilize air and surfaces.
Most common wavelength 253.7 nm and 184.9 nm. The 184.9 nm radiation can produce ozone. UV light can damage the eyes. and cause "sun" burn.
Works by damaging DNA (cross linking).
Packages (if any) must be transparent to UV.
Effectiveness depends on energy of beam. Energy range from 1 to 12 MeV.
Penetration into surfaces is somewhat limited.
Radiation can discolor and damage some plastics (including acetals and PTFE).
Radiation can cause PVC polymers to release Cl2 gas.
Exhibits good penetration of most materials.
Works by damaging DNA (chain breakage).
Can be used to sterilize metal items (like culture loops).
Commonly used for heat sensitive liquids and gases.
Filtation is often an absolute, reather than problistic process.