In a professional lab setting, you can never be too hygienic or safe. Scientific industries often present specific safety challenges in the handling of biological specimens and hazardous materials.
In order to ensure laboratories and lab personnel remain as safe as possible, we have specific services in place. Services like lab equipment disposal, biosafety cabinet maintenance and cleanroom repairs are all dedicated to upholding cleanliness and safety.
In addition to these, procedures such as lab equipment decontamination and sterilization are also established to keep labs hygienic. Sterilization is essential to keeping lab equipment, materials and samples clean and functional. In this post, we’ll identify and discuss the five methods of lab sterilization that will keep you and your materials safe.
1. Wet Heat (Autoclaving)
Autoclaving is the most popular method of lab sterilization. This process uses pressurized steam to heat the item that must be sterilized. Autoclaving is an incredibly effective procedure. It will kill all microbes, spores and viruses. However, for some specific biosafety levels, higher steam temperatures or longer incubation periods are necessary.
The pressurized steam generated from autoclaves holds seven times more heat than water at the same temperature. Additionally, when it comes in contact with the material, the heat is instantly delivered and even penetrates a more dense, thick surface.
The speed and efficiency at which autoclaving sterilizes materials is what makes it the most popular choice. Since these are vital to a lab’s daily operations, it is important to service and repair your autoclaves regularly.
2. Dry Heat (Baking or Flaming)
Dry heat sterilization is considered the most effective method for fats, oils, powders or materials more likely to rust. Essentially, the main difference between dry heat and autoclaving is the absence of water or steam in dry heat sterilization.
Basically, dry heat sterilization involves raising the temperature of an item to 325 degrees Fahrenheit or higher under normal air pressure. We use dry heat sterilization on a daily basis, and not just in lab settings. When we cook meat or poultry in an oven, we’re utilizing dry heat sterilization to remove the bacteria and microbes.
With dry heat, higher temperatures of heat are required to properly sterilize the item.
Filtration is a method of lab sterilization that does not require heat. Additionally, it is the only method of sterilization that relies on force to separate microbes or bacteria in liquid rather than kill. Filters function by passing the liquid solution through a filter with pore diameters too small for microbes to move through. Essentially, the filter removes the organisms from the solution.
When it comes to proper sterilization, the filters used are usually membranous filters made from cellulose esters. In order to remove bacteria, they usually have an average pore diameter of 0.2um. However, if viruses or phage is a concern, filters are not a good technique for sterilization. These organisms can usually travel through even the finest of filters.
Heating and filtration can be effective methods of sterilization. However, in many cases the heat can damage the materials that need to be sterilized. This is where the uses of chemicals and solvents can come in handy.
While the chemicals used to sterilize are hazardous to humans, they won’t damage the items that must be sterilized. Even gases are solvents that can sterilize items. They provide swift sterilization by quickly penetrating the materials without the use of accelerated heat.
Chemicals and solvents sterilize by denaturing proteins through procedures that require water. In order to be effective, they must be diluted by 60-90% in water.
Hydrogen peroxide, nitrogen dioxide, glutaraldehyde and formaldehyde solutions are some of the most common chemical sterilizers. While these solvents are excellent at killing microbial cells, they have no effect on spores.
Radiation use can make excellent techniques for lab sterilization. Ultraviolet light, x-rays and gamma rays are the kinds of electromagnetic radiation that swiftly pulverize DNA.
In air, UV has limited penetration capabilities. Basically, what this means is that the sterilization will only occur in a relatively small area directly within the lamp. However, it’s one of the more safe methods of sterilization. It’s often used in small areas such as laminar flow hoods.
Gamma and x-rays have excellent penetration capability. While this makes them inherently more dangerous, it also means they’re effective for sterilization on a much larger scale.
At S.E.P.S., we’ve made lab safety and hygiene our practice and our top priority. Lab equipment sterilization is absolutely essential to keeping labs safe and operational. Some lab environments can present certain risks, and we make it our mission to eliminate them.