What is Autoclaving?
Autoclaving is the most effective method of sterilizing the lab equipment specially for liquid handling products to kill harmful bacteria, viruses, fungi, and spores. The autoclaving process takes advantage of the phenomenon that the boiling point of water (or steam) increases when it is under high pressure. It is performed in a machine known as the Autoclave where high pressure is applied with a recommended temperature of 250°F (121°C) for 15-20 minutes to sterilize the equipment. Autoclaving or steam sterilizer is used in several industries including medicine, dentistry, microbiology and veterinary science.
The Steam Digester, now commonly known as a pressure cooker, was invented by French physician Denis Papin around 1681 for food preparation. The autoclave was re-invented for medical and scientific use by Charges Chamberland in 1879.
Finally, modern autoclave technology was introduced with the first pressure steam sterilizer in 1933 that controlled sterilizing performance by measuring the temperature in the chamber. Over time, many technologies such as pre-vacuum cycles in 1958, and steam-flush pressure-pulse in 1987 have been introduced with an enhanced version of autoclave.
How Does an Autoclave Work?
When the autoclave door is locked with a sealed chamber, a vacuum pump removes all air present in the chamber and replaces it with steam. Now, pressure is applied on steam to achieve desired sterilization for the desired time duration. Once the cycle is complete, the steam is exhausted and lab equipment removed from the chamber carefully.
For more detailed explanation of the various phases of a sterilization cycle, please refer to the list and image shown below:
- Purge Phase: The air must be removed from the chamber during the first phase of sterilization cycle known as Purge Phase. The vacuum system given in the autoclave machine, is designed to replace the air with steam in the sealed chamber.
- Exposure (Sterilization) Phase: After the air is removed, the sterilizer drain closes and steam is continuously admitted in the chamber, which results in the increment of pressure and temperature inside the chamber at desired level. Now the cycle enters the exposure phase and the lab equipment is held at the sterilization temperature for a recommended period of time.
- Exhaust Phase: In the last, pressure is released from the chamber through an exhaust valve and the interior is restored to ambient pressure.
Advantages/ Disadvantages of an Autoclave
- Economical or cheap
- Short procedure time
- Provides good penetration on all surfaces
- No additional chemicals or disposables required
- Moisture retention
- Carbon steel can get damaged due to moisture exposure
- Only stainless steel instruments and plastics which can bear the heat be sterilized
How is the autoclave process relevant to liquid handling instruments?
It is important to keep all lab equipment free from microorganisms, bacteria, fungi and other hazardous contaminants for the safety of lab technicians and prevent cross contamination between experiments. In some cases, spot sterilization or external cleaning is not enough to ensure sterility of the instruments. Steam Sterilization or autoclaving is a simple and quick way to decontaminate. Sterilization is achieved by exposing liquid handling products to saturated steam at high temperature (approx. 121°C) for desired period of time.
Autoclaving process is not appropriate for many materials due to the high temperature involved. Before autoclaving, ensure that the liquid handling device to be placed in the autoclave is compatible for steam sterilization at the recommended temperature.
Microlit products: Conveniently autoclavable
Microlit has designed liquid handling products which can be easily autoclaved to ensure technician safety and prevent cross-contamination in experiments. Microlit micropipettes are fully autoclavable at 121°C, 15 psi for a duration of 15-20 mins, which means that our pipettes can be placed in an autoclave without disassembling any parts or components. This enables convenient autoclaving in the lab.
Microlit bottle top dispensers can also be autoclaved for sterilization at 121°C, 15 psi for a duration of 15-20 mins. However, the piston needs to be disassembled from the assembly before autoclaving. The housing and the piston can then be sterilized separately. For complete autoclaving instructions, please refer to the instruction manual of Scitus bottle top dispenser.
To learn more about Microlit products and their autoclavability, please visit the Microlit products page https://www.microlit.us/shop/.