The primary function of a CO2 incubator is to provide an ideal growth environment for cultured cells. Since these may represent months, even years, of valuable research, incubator reliability and stability are essential. To avoid incubator failure and minimize risk to precious, often irreplaceable cultures, it is wise to establish and maintain a CO2 incubator preventive maintenance program. We spoke with Jon Pulse, product engineer at NuAire, Inc., to learn more about effective ways of achieving this.
“If an incubator stops running, or conditions are not kept stable, there is a greatly increased risk of cell death,” reports Pulse. “A good first step to establishing an effective CO2 incubator preventive maintenance program is to consult the information provided by the manufacturer. All NuAire CO2 incubators are supplied with a comprehensive checklist detailing both general and preventive maintenance steps and the suggested frequency with which these procedures should be carried out.” Checks recommended by NuAire include visual inspection to confirm displays and indicator lights are working normally, evaluation of the incubator’s ability to recover to correct gas % within a specified time, and examination for gas or water leaks.
The purpose of a CO2 incubator preventive maintenance program is to ensure optimal incubator performance and avoid contamination. However, with multiple end-users interacting with an incubator, this can easily be negated if best practices aren’t followed. These include the use of appropriate personal protective equipment (PPE), and adherence to good laboratory practice, aseptic technique, and standard operating procedures (SOPs) based on the laboratory’s biosafety level. “Training should focus on minimizing the risks to cell health, for example preventing disruptions to the growth chamber by keeping door openings to a minimum,” explains Pulse. “Documenting incubator use and preventive maintenance activities acts as a reminder to perform essential tasks.”
According to Pulse, the frequency of cleaning a CO2 incubator will vary according to factors such as the cleanliness of the laboratory environment, the number of people using the incubator, and the type of cells being cultured. “It is important to clean the exterior of the incubator to remove contaminants that have the potential to enter the growth chamber as the door is opened,” he says. “This may be required as frequently as once per week in high traffic laboratories, but it is easily accomplished using a solution of mild detergent or bleach in single distilled water.”
Pulse also recommends cleaning the interior of the incubator one to two times per month with a noncorrosive disinfectant such as 70% isopropyl alcohol or 70% ethanol. “Special attention should be paid to seams and crevices where contaminants may accumulate,” he notes. “For example, the door gasket is a high-risk area for contamination. Incubators designed with one continuous interior surface, or a removable, autoclavable door gasket can reduce the risk of contamination.” Pulse stresses that one of the most critical preventive maintenance tasks is to clean the water pan; this should be performed weekly to minimize contaminants and prevent the cells from drying out.
Modern incubators offer multiple features that reduce the risk of contamination, the most important of which is the closed loop HEPA filter. “Incubators without HEPA filtration are considerably more susceptible to contamination with bacteria, viruses, molds, or mycoplasmas,” reports Pulse, adding that NuAire incubators HEPA filter the entire growth chamber atmosphere once every 20 minutes to rapidly remove any such contaminants that may have been introduced during door opening.
“To maintain effectiveness, filters should be changed regularly according to the preventive maintenance program,” he says. “Air inlet HEPA filters have an average lifespan of three to six months and are compromised by extended use. We also recommend changing the gas supply line filters (CO2 and N2) every fifth tank or when the filter is discolored, and the air pump capsule HEPA filter every two years.”
To maximize the lifetime of a CO2 incubator, it is important to consider where in the laboratory it will be positioned. “The ideal location is a low-traffic area with a stable temperature, away from strong air currents such as air-conditioning vents that may be a source of contaminants,” says Pulse. “This will ensure the preventive maintenance program remains effective and will help to ensure many years of consistent, reliable service.”
To learn more about establishing a preventive maintenance program for your CO2 incubator, or to speak with one of the specialists at NuAire, please visit www.nuaire.com.