CO2 Incubators: Precision Tools Driving Drug Discovery Success

CO₂ incubators are essential for cultivating cells or tissues under controlled conditions in drug discovery labs. This article explores the significance of CO₂ incubators with an emphasis on the importance of rigorously maintaining and monitoring incubation conditions. Effective cell culturing techniques require precise, real-time control of numerous environmental metrics. Maintaining sterility is also paramount to prevent contamination and downtime. 

From environmental stability monitoring to regular quality checks, there are practical strategies that can be implemented to ensure the reliability of cell cultures. Understanding and maintaining these conditions are key factors in building the foundation for drug discovery pipeline success.

Defining the importance of CO₂ incubation conditions

Several primary environmental parameters require stringent monitoring and control during cell culture incubation to ensure cell viability, proliferation, and an accurate representation of in vivo conditions. Deviations from these parameters (within or between incubators) can result in noisy, inconclusive data or even cell death. Furthermore, cell culturing conditions can vary per experiment and cell type, so it is important to be well-informed about the requirements of the cells in your care. In the drug discovery pipeline, there is typically a focus on maintaining consistent atmospheric and human physiological conditions, including:

• Carbon dioxide (CO₂) concentration: Commonly used at five percent CO₂ but may vary based upon culture medium pH buffering system¹
• Oxygen (O₂) concentration: Can vary from 1-20 percent depending on cell- or tissue-specific conditions like hypoxia or hyperoxia¹
• Temperature: Maintained at approximately 37 degrees Celsius (98.6 degrees Farenheit)¹
• pH level: A slightly acidic pH of 7.2-7.4 is typically used to emulate bloodstream biochemistry but may vary when studying health conditions such as cancer¹
• Osmolarity: osmotic stress is prevented by adjusting cell culture osmolarity in a cell- or tissue- specific manner (typically 260–320 milliosmole)1
• Humidity: Maintained at 85-95 percent to prevent evaporation and maintain osmolarity of cell culture media²
• Gas flow and distribution: Even dispersal of CO₂ and O₂ levels must be maintained throughout the incubator to prevent localized variation across cultures¹
• Sterility: Typically maintained via HEPA filter and UV decontamination methods in combination with aseptic techniques and regular cleaning¹

Effective incubator and cell culture monitoring solutions

Success in a drug discovery pipeline lab requires a combination of tools and software for monitoring and controlling cell culture conditions. A holistic approach to monitoring both the environment and the cell cultures is fundamental to guarantee precision, reproducibility, and data integrity.

Incubators with integrated sensors, controls, and data logging

Most modern CO₂ incubators come equipped with controls for temperature, humidity, and gas concentrations. Gas sensors are crucial for continuous monitoring of atmospheric conditions. Osmometers and pH meters may also be integrated to validate the osmolarity and pH levels of culture media. These features allow real-time monitoring and adjustment of the incubation environment as needed. Some advanced models also offer data logging capabilities that record the important metrics over time, which supports data reproducibility and validation. This is especially important for experiments or trials with a long duration.

Environmental monitoring systems (EMS) and software

An EMS integrates multiple sensors to monitor key parameters such as gas concentrations, relative humidity, and temperature. These systems provide a centralized platform for real-time data collection. They can be configured to provide alarms when triggered by changes in the culturing environment.  Additionally, laboratory information management system (LIMS) software can be integrated into the EMS to manage and track experimental data, including cell culture conditions and experimental results. Incubators may also be equipped with automated culturing systems using control software that communicates with equipment, like robotic arms and liquid handlers. This software reduces human error and ensures proper coordination of experiments during high-throughput screenings. Together, these three systems can improve reproducibility, data organization, traceability, and demonstrate adherence to regulatory standards and guidelines.

Cell culture monitoring methods

CO₂ incubators can be equipped with inverted microscopes that enable digital imaging capabilities for monitoring cell morphology, density, and behavior in real time. Alternately, instead of adding an inverted microscope into your incubator, some companies have developed small incubation chambers that are staged directly upon the inverted microscope. This method facilitates the use of automated live-cell imaging systems that can capture time-lapse images or gather data for long-term experiments. Aside from cell visualization, contamination must also be monitored. The most likely incubator infection is caused by mycoplasma due to their small size (0.1-0.3 microns) and ability to slip through the incubator’s HEPA filtration systems. Currently, PCR is the most used method for detecting mycoplasma and specialized kits exist for this purpose.

Are you ready to scale up? 

The process of scaling up from small-scale cell culture to bioreactors can be daunting. To reduce stress upon yourself and your cell lines, some preliminary quality control work must be done. First, prepare a blueprint of expected results by optimizing your culturing conditions and ensuring that your experimental data is rigorously gathered and well-reviewed. Next, authenticate your cell lines via DNA and karyotype profiling, determine cell viability and purity, and test for contaminating organisms like mycoplasma. Ensure that the monitoring methods you’ve established in the small-scale will be feasible and available in the bioreactors. Enter the process with specific expectations about metrics like expected cell density and growth rates, product quality or consistency, and devise methods for ensuring comparability with your small-scale results.

In drug discovery labs, CO₂ incubators are indispensable tools used in the meticulous process of controlled cell or tissue cultivation. The emphasis on rigorous maintenance and monitoring of incubation conditions can’t be overstated as they are crucial for reliability and reproducibility of experiments. Establishing reliable conditions is required prior to scaling up production in bioreactors. With an unshakeable commitment to quality control, CO₂ incubators can serve as the basis for groundbreaking experiments and the development of novel pharmaceuticals.

References:

1. Bal-Price, Anna, and Sandra Coecke. 2011. “Cell Culture Techniques.” Neuromethods, 1–25. doi:10.1007/978-1-61779-077-5_1.
2. Pamies, David, Marcel Leist, Sandra Coecke, Gerard Bowe, David G Allen, Gerhard Gstraunthaler, Anna Bal-Price, et al. 2021. “Guidance Document on Good Cell and Tissue Culture Practice 2.0 (GCCP 2.0).” ALTEX 39: 30–70. doi:10.14573/altex.2111011.