CO2 Incubators

Humidity control plays an important role in many basic cell culture applications. Passive humidity control in a CO₂ incubator relies on a water pan at the base of the chamber to naturally evaporate water, maintaining stable but unregulated humidity levels. Active humidity control, on the other hand, uses advanced sensors and systems to regulate precise humidity at the desired level. One example of such a system routes chamber air through an RH reservoir to become humidified. Active systems recover to 90% ± 5% RH within 25 minutes of a door opening. These systems are ideal for critical applications such as stem cell research or tissue engineering where maintaining a highly controlled humid environment is essential.

Proper cleaning of a CO₂ incubator involves these steps:

• Turn off the CO₂ incubator and disconnect it from the power source.
• Remove shelves, water pans, and other removable components. Clean these parts separately with 70% isopropanol or ethanol.
• Wipe down all interior surfaces with a lint-free cloth and a disinfectant solution approved for use in laboratory equipment. Avoid using bleach unless specifically recommended.
• Refill and clean the water pan weekly to reduce microbial growth.

Decontamination Cycle: Run the high-temperature decontamination cycle (145 °C) every 3–6 months, or whenever contamination is suspected. This process decontaminates all internal surfaces, helping to minimize bacteria, fungi, and spores. Components such as shelves can remain inside the chamber during the cycle.

References: NuAire Maintenance Guide, CO₂ Incubator Surface Cleaning Video 

Filter Maintenance: HEPA filters in CO₂ incubators should be replaced every 12 months under normal use to maintain clean airflow and reduce contamination risk. For CO₂ gas supply lines, disk filters should be replaced every fifth tank or when discoloration is visible. Regular filter replacement ensures proper airflow, contamination prevention, and optimal performance for cell culture research.

References: NuAire Maintenance Guide, Changing Capsule HEPA Filter Video, Changing HEPA Filters Video 

To prevent contamination in a CO₂ incubator, follow these best practices:

• Clean the chamber and components weekly with non-corrosive disinfectants specifically approved for use in laboratory CO₂ incubators.
• Use NuAire’s in-chamber HEPA filtration system, which removes 99.99% of airborne contaminants, ensuring clean conditions for your cell cultures.
• Avoid frequent door openings, as this disrupts the controlled environment's temperature range, humidity control, and increases the risk of contamination.
• Use distilled or deionized water in the water pan to prevent scaling and microbial growth.
• Add copper sulfate (0.5 ppm) to the water pan to inhibit microbial cell growth before contamination can occur. Copper is a natural antimicrobial agent and offers an additional layer of protection against mold and bacteria.
• Consider using copper alloy shelves in your NuAire CO₂ incubator. Copper surfaces naturally reduce microbial loads, which reduces risk and helps to maintain cleanliness, making them ideal for contamination-sensitive environments like stem cell research and microbiology.
• Regularly run the high-temperature decontamination cycle to decontaminate all internal surfaces, ensuring the chamber is ready for optimal cell growth experiments.

References: NuAire Buyers Guide to Contamination Prevention, Closed-Loop HEPA Filtration Video 

Use single distilled or deionized water with a maximum purity of 1 megaohm in your CO₂ incubator water pan. This prevents scaling, mineral deposits, and microbial growth. For additional contamination prevention, you can add copper sulfate (0.5 ppm). Replace the water weekly and clean the water pan to maintain a clean environment for cell cultures.

References: NuAire Proper Maintenance Guide, Filling the Water Pan Video 

• Direct Heat CO₂ Incubators: Utilize heating elements to warm the chamber. These models recover faster after door openings and are lightweight, making them ideal for high-frequency access workflows.
• Water Jacket CO₂ Incubators: Use a water-filled jacket to distribute heat evenly. These models offer greater thermal stability and retain heat longer during power outages, making them ideal for long-term experiments or sensitive applications.

Choosing between the two depends on your lab's needs: frequent access or mobility favors direct heat, while water jackets suit critical, long-term studies.

Reference: NuAire White Paper: Direct Heat vs. Water Jacket CO₂ Incubators 

A decontamination cycle in a CO₂ incubator involves heating the chamber to 145°C for 8–14 hours. This process decontaminates all internal surfaces and components by significantly reducing the presence of bacteria, fungi, and spores. The cycle is fully automated, and internal components such as shelves can remain inside throughout. This feature is essential for maintaining a clean, controlled environment in laboratories focused on cultivating cancer cell lines, advancing tissue engineering, and conducting preclinical drug screening—where minimizing contamination risk is critical to experimental integrity.

• CO₂ Calibration: Use a gas analyzer to measure the CO₂ level. Adjust offsets on the incubator’s control panel to match the analyzer’s readings. NuAire’s Service team recommends performing an “Open Door Zero-Span Calibration,” which involves opening the chamber during part of the process for increased accuracy.

• Temperature Calibration: Verify chamber temperature with a certified thermometer and adjust settings if necessary.

Calibration should be performed by a trained professional every 6–12 months or after major maintenance. Improper calibration can significantly affect incubator performance and lead to inconsistent cell culture results. For assistance, contact your NuAire sales representative or technical support.

References: OM0246 Rev 9, Section 9, Relative Humidity Calibration Video, RH Sensor Calibration Video, Temperature Sensor Calibration Video, O₂ Sensor Calibration Video 

Answer: Troubleshooting steps include:

• Ensuring the door isn’t being opened excessively, which can destabilize internal conditions.

• Verifying that the CO₂ gas supply is properly connected and functioning.

• Inspecting and replacing filters if airflow appears restricted.

• Calibrating sensors to correct inaccuracies.

For persistent issues, contact NuAire technical support at 1-800-328-3352 or consult your local NuAire representative.

Reference: OM0246 Rev 9, Troubleshooting Section 

A CO₂ incubator creates an optimal environment for cell culture growth by precisely controlling temperature, humidity, and CO₂ levels. Temperature is regulated using direct heat or a water jacket, while a CO₂ gas supply maintains pH balance in the culture medium. Humidity, maintained via a water pan or active system, prevents media desiccation. HEPA filters ensure clean airflow, reducing contamination risks. This controlled environment is essential for cell culture applications like tissue engineering, stem cell research, and microbiology.

Reference: NuAire Buyers Guide 

• Capacity: Match chamber size to your lab’s workload; smaller units suit compact spaces, while larger ones handle high-throughput needs.

• Contamination Control: Choose models with HEPA filtration, decontamination cycles, and cleanable surfaces for clean environments.

• Special Features: Opt for active humidity control or hypoxia capabilities for advanced applications like aging studies or cancer research.

For a comprehensive guide, refer to the NuAire Buyers Guide.