For as long as humans have performed surgery, we have suspected that we should go out of our way to keep equipment free of infectious materials. While early methods were expectedly primitive—the ancient Egyptians favored petroleum derivatives such as tar as their antiseptic of choice—there has always been an emphasis on keeping instruments exceptionally clean. Sterilization took its quantum leap in the late 17th century with the invention of the pressure cooker, which not only cooked but also cleaned using pressurized steam. Developments in effective sterilization have continued to this day. There are four primary methods of sterilizing medical instruments in use today, and if you’re considering starting a practice of your own, they will all be imperative in your operations.
Pressurized Steam
The medical-grade development of Denis Papin’s pressure cooker, the autoclave, indeed shuts itself to the outside world in order to achieve extremely high pressure. Under this pressure, high-temperature steam denatures the cells of microorganisms such as viruses, bacteria, and mold spores, causing cell death and lending medical instruments the safety they require. Settings ranging from laboratories to tattoo parlors make use of the autoclave to sterilize metal and glass equipment.
Radiation
Legendary American jurist Louis Brandeis once wrote that “sunlight is the best disinfectant.” Justice Brandeis spoke of sunlight figuratively in terms of legal transparency, but nevertheless, the disinfecting properties of ultraviolet light, along with other forms of radiation, are a prevalent means of medical sterilization. Radiation sterilizes by degrading DNA, which rapidly kills microorganisms. Non-ionizing forms of radiation for sterilization, such as infrared and ultraviolet light, are popular in high school science laboratories. Meanwhile, ionizing radiation such as X-rays and gamma rays is typically limited only to hospitals and manufacturing facilities that are qualified to deal with radioactive material.
Gas Sterilization
In some cases, exposure to powerful chemicals achieves the sterilization necessary for medical instruments without having to employ radiation or pressure. Ethylene oxide gas kills microorganisms without necessitating the high temperatures of an autoclave, making it an ideal choice for plastic instruments that could not withstand high heat without melting, such as syringes. Ozone gas, the form of oxygen that insulates our planet, has powerful disinfectant properties that medical facilities use regularly.
Plasma Sterilization
Plasma sterilization combines two methods of sterilizing medical instruments, namely chemical gas and steam, into one highly effective form. A plasma sterilizer heats hydrogen peroxide to a gaseous phase, then further destabilizes it by elevating it to plasma, the rare and unstable fourth phase of matter. The ions that plasma creates rapidly oxidize any cells inside the chamber, causing cell death and resulting in sterilized instruments.
