How to Use an Incubator in the Laboratory: A Step-by-Step Guide

The laboratory incubator is a cornerstone of biological and medical research. Whether you’re cultivating cell cultures, growing microorganisms, or conducting biochemical assays, knowing how to use an incubator in the laboratory is a fundamental skill for any scientist or technician. This is because this controlled environment chamber provides stable conditions—primarily temperature, humidity, and CO₂ levels—to support and promote the growth of biological samples.

It’s important to note that incorrect usage can lead to contaminated experiments, unreliable data, and wasted resources. To help you avoid these pitfalls, this comprehensive guide will walk you through the essential steps and best practices for operating a laboratory incubator effectively and safely.

What is a Laboratory Incubator?

Before diving into the “how,” let’s quickly define the “what.” In essence, a laboratory incubator is an insulated chamber that maintains optimal environmental conditions for the growth of cells, tissues, or microorganisms. The most common types are:

• Standard Thermal Incubators: For general microbiological use.
• CO₂ Incubators: Essential for mammalian cell culture, which requires a specific CO₂ concentration (typically 5%) to regulate pH.
• Shaking Incubators: Combine incubation with agitation for growing bacterial cultures in liquid broth.
• Refrigerated Incubators: For lower temperature applications.

Step-by-Step Guide: How to Use an Incubator

Now, let’s get into the detailed process. Follow these steps to ensure you are using your laboratory incubator correctly.

Step 1: Pre-Use Preparation and Checks

1. First, consider the Location: Ensure the incubator is placed on a stable, level surface away from direct sunlight, drafts, and heat sources. Additionally, leave ample space around it for ventilation.
2. Next, Inspect the Chamber: Visually inspect the interior for any spills, contamination, or damage. Clean it if necessary (see Step 5).
3. Then, Check the Water Reservoir (for humidity): If you are using a humidified CO₂ incubator, check the sterile water reservoir. To prevent contamination and maintain humidity, fill it with sterile, distilled water to the indicated level.
4. Finally, Power On: Switch on the incubator and allow it to stabilize.

Step 2: Setting the Parameters

1. Set Temperature:Begin by using the control panel to set the desired temperature. Common temperatures are:
   • 37°C: For human and mammalian cell cultures and many human pathogens.
   • 25-30°C: For fungal cultures.
   • 65°C: For thermophilic bacteria.
2. Set CO₂ Level (for CO₂ incubators): Following that, set the CO₂ level, usually to 5%. The incubator will automatically regulate this using a sensor (e.g., thermal conductivity or infrared).
3. Allow for Stabilization: This is a critical but often overlooked step. After setting the parameters, allow the incubator to run empty for several hours or overnight. Furthermore, use independent thermometers and CO₂ sensors to verify that the chamber has reached and maintains the setpoints before introducing your valuable samples.

Step 3: Loading Your Samples

1. First and foremost, Personal Hygiene: Wear appropriate personal protective equipment (PPE)—a lab coat, gloves, and safety glasses.
2. Then, Organize the Interior: Arrange samples logically, leaving space between them to ensure proper air circulation. Most importantly, avoid blocking vents or sensors.
3. Work Quickly and Efficiently: The key here is to open the door only when necessary and for the shortest time possible. This is because every time the door opens, there is a rapid loss of temperature, CO₂, and humidity, which can stress your cultures.
4. Finally, Use Proper Labeling: Ensure all culture vessels (plates, flasks) are clearly labeled with your name, date, and sample ID.

Step 4: Routine Monitoring and Maintenance

1. Daily Checks: On a regular basis, monitor and record the temperature, CO₂ level, and humidity (if applicable) at least once a day. Fortunately, many modern incubators have data logging capabilities.
2. Weekly/Monthly Maintenance:
   • Water Reservoir: Similarly, top up or replace the sterile distilled water regularly to prevent the growth of algae and biofilm.
   • Cleaning: Likewise, perform routine cleaning to prevent contamination.

Step 5: Cleaning and Decontamination

It cannot be overstated that regular cleaning is non-negotiable for how to use an incubator in the laboratory successfully.

1. First, establish a Schedule: Set up a strict cleaning schedule (e.g., monthly or quarterly, depending on use).
2. Then, follow this Procedure:
   • To start, turn off and unplug the incubator.
   • After that, remove all shelves and accessories.
   • Next, clean all interior surfaces, shelves, and the water pan with a mild detergent or a laboratory-grade disinfectant like 70% ethanol or a diluted bleach solution.
   • Subsequently, rinse thoroughly with sterile water (if using bleach) and wipe dry with a clean lint-free cloth.
   • Finally, allow all parts to dry completely before reassembling and restarting the incubator.

Best Practices and Safety Tips

To further enhance your practice, keep these points in mind:

• Above all, Avoid Contamination: Never place non-sterile items inside the incubator. As a best practice, wipe down the outside of all culture vessels with 70% ethanol before placing them inside.
• Calibration: Similarly, have the incubator’s temperature and CO₂ sensors professionally calibrated at least once a year.
• Emergency Plan: It’s also wise to know what to do in case of a power outage. In other words, have a plan to save critical cultures.
• Safety First: Always remember to be cautious when opening the door of a hot incubator. Moreover, be aware that incubators can harbor potential pathogens—therefore, always treat contents as potentially biohazardous.

Conclusion

In summary, mastering how to use an incubator in the laboratory is more than just setting a temperature. Instead, it involves careful preparation, precise operation, diligent monitoring, and rigorous cleaning. By following this step-by-step guide and adhering to best practices, you can create a stable and contamination-free environment for your biological samples, thereby ensuring the integrity and reproducibility of your scientific experiments.

Do you have any tips or questions about using a lab incubator? Share them in the comments below!