Comparing Lab Sterilization Methods

Sterilizing equipment is a very important procedure in any lab. This has led to a proliferation of technology intended for the purpose. This technology can use a variety of sterilization methods, from gas sterilization to autoclaving. Each method has its strengths and weaknesses, so it is important that anyone managing a lab chooses their sterilization methods carefully.

Methods Of Laboratory Sterilization

So, are you ready to perform laboratory sterilization? You are sitting on one of your favorite lab stools. Right? Let’s dive deep into methods of laboratory sterilization!

Gas

Gas sterilization is often used as an alternative to autoclaving. It is more commonly used in medical facilities than in labs. This is because common medical devices like catheters and stents are sensitive to moisture, making them unsuitable for autoclaving. However, some labs do use gas sterilization when working with specialty equipment that is sensitive to moisture.

The gas most often used for this application is ethylene oxide. It is effective on a variety of microorganisms. However, it is highly toxic.

Radiation

Radiation is perhaps the second-most commonly used method of sterilization in modern labs, behind only autoclaving. The types of radiation used for labs include UV rays, x-rays, and gamma rays. UV rays are the safest but are relatively weak compared to gamma rays and x-rays. While gamma rays and x-rays are very effective at killing microorganisms, prolonged exposure to these rays can be extremely dangerous.

Solvents

Solvents were commonly used in labs before autoclaves became widespread. Isopropanol and ethanol are the most commonly used solvents in professional labs. These solvents cannot be used by themselves as they need water to create the chemical reaction that kills microbes. Isopropanol and ethanol are usually diluted to 90% strength for sterilization.

Solvents are effective at killing microbes. However, they have no effect on spores. Any lab that works with fungi cannot consider using solvents for sterilization.

Filters

Filters are only useful for specific applications in a lab. Most labs will only use filter sterilization to sterilize solvents quickly. Modern cellulose ester filters can effectively remove bacteria and spores. However, viruses and phages are small enough to pass through filters. Filter sterilization is not a good option for any lab that may have to deal with phages or viruses.

Dry Heat

Dry heat sterilization, also known as baking or flaming, is another sterilization method that was popular before the advent of autoclaves. Some labs still use this method for moisture-sensitive items. Unlike an autoclave, which uses steam, dry heat sterilizers simply use hot air.

Hot air does not carry as much latent heat as steam, making it a less efficient method of sterilization. This means that a dry heat sterilizer has to operate at a significantly higher temperature than an autoclave to achieve the same level of sterilization. For example, the standard temperature most often used in autoclave cycles is 121 degrees Celsius. However, many dry heat sterilizers use a temperature of 160 degrees Celsius to achieve the same level of sterilization.

Autoclaving

Autoclaving is easily the most popular method of sterilization in professional labs. A lab autoclave uses steam to sterilize items. Steam carries seven times as much latent heat as air, making it a far more effective method of sterilization. A steam autoclave can effectively kill all forms of microorganisms, including bacteria, viruses, and spores. Autoclaves are also very safe when operated correctly.

Combining Methods For Full Coverage

Some labs will be able to use autoclaves for all their sterilization needs. However, many labs have to sterilize items that are sensitive to moisture or are too big to fit in the autoclave. These days, it is common for these labs to use a combination of autoclaving and radiation sterilization to ensure that everything can be sterilized.