Lab Incubator Maintenance and Care

Keeping a lab incubator in prime working condition requires a commitment to regular maintenance and cleaning. Here, we review what needs to be done and when. We also share best practices from experts that can help make lab incubator maintenance and care less arduous.

Importance of regular maintenance and cleaning

CO₂ incubators provide an optimal environment for cell growth by maintaining a humidified atmosphere with controlled temperature and CO₂. They have utility for applications spanning drug discovery and stem cell research through to tissue engineering and in vitro fertilization, any of which can be compromised by incubator malfunction or contamination.

“To ensure trouble-free functioning of CO₂ incubators, proper and timely maintenance is essential,” reports Alex Atmadi, Technical Sales Manager at Esco Technologies. “This should include regular checking of the CO₂/N₂ gas tank levels; routine calibration of gas, temperature, and humidity sensors; and replacement of expendable parts such as filters or UV lamps as required.” Derek Sokolowski, Product Manager–Cell Culture at PHC Corporation of North America, adds that users should also ensure that CO₂ incubators are operating within the correct inlet pressure range. “Under or over pressurization can cause damage to the internal components, which leads to cell culture failure,” he says.

Implementing a regular cleaning and disinfection schedule is equally important. “Contamination can result from carelessness in aseptic techniques and unnoticed splashes from cell culture vessels,” reports Rodrigo Ribeiro da Silva, Ph.D., Regional Marketing Manager at Eppendorf Group. “To minimize the risk of contamination, regular cleaning and disinfection is essential. This process can be simplified by good functional design of equipment, which also helps to prevent contamination from occurring in the first place.”

Maintenance best practices

While the type and frequency of maintenance that is required will vary depending on the incubator model and how heavily it is used, several best practices prevail. First, the incubator should never be placed directly on the floor since this will allow dust and dirt to enter the chamber every time the door is opened. Positioning within the lab should also be considered. “A CO₂ incubator works properly when it is installed in a location that reduces the chances of airborne contaminants entering it,” says Sokolowski. “A low foot traffic location away from drafts, such as those coming from air-conditioning vents, is recommended.”

Researchers are also advised to regularly check the tightness of the glass door seal and any hinge screws, and to confirm that the glass door latch is working properly. A build-up of condensation on the glass can indicate a problem. In addition, Atmadi suggests regularly performing a quick functional check of the operating panel and device control. “Other things to look for include discoloration of gas supply line filters and signs of corrosion within the humidity pan, which can be caused by using chlorinated tap water,” he says. “Sterile distilled water is recommended for refilling the humidity pan; other types of water are unsuitable for incubators and should be avoided.”

Cleaning best practices

In general, cleaning a lab incubator involves transferring samples to another unit, removing parts such as shelves, racking, and the humidity pan, and wiping everything down with 70% ethanol. Removable parts may also be autoclaved. The incubator can then be reassembled prior to activation of the decontamination/sterilization cycle program. A common mistake here is to use neat ethanol instead of a 70% solution. “Neat ethanol coagulates and dehydrates proteins so quickly that a layer of relatively impermeable denatured protein forms at the exterior of bacterial cells to prevent further alcohol diffusion,” explains Sokolowski. “With 70% ethanol, the process is slow and thus more effective at killing contaminants than higher concentrations.”

Decontamination/sterilization cycles are typically based on UV light, hydrogen peroxide (H₂O₂) nebulization or high temperature disinfection. “A main drawback of hydrogen peroxide nebulization is that it requires handling of a toxic reagent,” cautions Ribeiro da Silva. “It also has a high associated risk of recontamination due to manual repositioning of the chamber components and the need to wipe down water vapor once the disinfection process is complete. If available, high-temperature disinfection with 140–180^oC dry-heat is often preferred since it requires only minimal preparation time and has the lowest chance of recontamination as the chamber can be used directly afterward.”

General recommendations for maintenance and cleaning

Daily

• Check the CO₂/N₂ gas tank levels
• Visually inspect the incubator for signs of wear and tear, malfunction or contamination

Weekly

• Perform a quick functional check of the operating panel and device control
• Empty the humidity pan, clean it, and refill with sterile distilled water

Monthly

• Check the tightness of the glass door seal and hinge screws, confirm that the glass door latch is working properly
• Inspect gas supply line filters for discoloration
• Carry out full cleaning and disinfection

As recommended by the manufacturer (or more frequently if required) and to be performed by a qualified service engineer

• Calibration of gas, temperature, and humidity sensors
• Change gas inlet filters
• Change HEPA/ULPA filters (if present)
• Change the UV lamp (if present)
• Change door gaskets
• Full functional testing of the operating panel
• Electrical safety check in accordance with regulations

Contamination-reducing design features

Modern incubators have various design features to minimize contamination and simplify the cleaning and disinfection process. These include seamless inner chambers with round corners, which leave nowhere for contaminants to hide, and easily removable shelves and racking, which make cleaning and disinfection less onerous. Other contamination prevention features to consider when purchasing your next incubator include split inner doors, which can especially be useful if frequent door openings are unavoidable, and the types of sterilization cycle options that are offered.