Dynamic gas mixtures with adjustable O2 and CO2 concentration in cell cultures study.
Starting from the pioneering studies made in the early 1900’s, the cell culture process has been developed and refined to become one of the most important and widely used experimental methods for the scientific research. The growth of cells is a complex process that requires appropriate and controlled conditions (such as pressure, temperature, and system pH) to be achieved. A crucial role is carried out by the gas mixture fluxed over the culture.
The instrument for the gas mixtures management must secure high precision outcomes over the whole experiment duration; high accuracy, great stability, and high repeatability are required. On the other hand, it’s also important to work with an instrument capable of creating gas mixtures dynamically adjustable since the variation of the conditions for a particular cell type can result in gene/protein/enzyme expression changes. For all these applications we propose the use MCQ Gas Blender 100 Series, an instrument specifically made to work with 3 components gas mixtures that offer a quick and easy way to efficiently manage the experimental condition of your cell culture.</p>
Common experimental setup.
One of the crucial aspects of the grown of cells in vitro is the complete control over the working parameters during the entire process. Even if the cell culture applications may vary widely from each other, growth medium represent one the most important of these parameters. The medium used is usually buffered with sodium bicarbonate/carbonic acid and for a proper cell grown the pH value must be strictly maintained constant. The amount of CO2 in the culture atmosphere directly affects the medium pH, therefore the control over the gas mixture in which cells are grown becomes another fundamental process parameter. Due to the low content of CO2 (<0,04%), the air isn’t a valid option for cell culture. In most of the common applications, the cells are grown in an atmosphere of 5-10% CO2, inside special CO2 incubators. The basic CO2 incubators make use of gas mixture cylinders (pre-mixed by the supplier) in which the amount of CO2 in the flow cannot be changed or adjusted by the user. Newer and more advanced incubators include a CO2 sensor for a feedback regulation of the amount of CO2 inside the chambers but are less common and more expansive than the basic ones.
Dynamic gas mixtures applications.
Working with static gas mixtures with a fixed or adjustable amount of CO2 represents now just the base of the cell culture applications. Since the last two decades until today many experiments have been successfully conducted with gas mixtures dynamically obtained and much more demands for instruments capable of controlling both O2 and CO2 relative amounts in the culture atmosphere. Fine control over the gas mixture allows those experiments, in which an induced hypoxic, hyperoxic or hypercapnic state is required, to be performed efficiently.
Dry air contains roughly 78.08% nitrogen, 20.95% oxygen, 0.92% argon, 0.04% carbon dioxide and other components in trace (mostly noble gases). A hypoxic gas mixture is by definition a mixture with a lower oxygen content compared with air. Basically, the amount of O2 in a hypoxic mixture goes from a minimum of 0% (this condition is called anoxia) to a maximum of 21%. On the contrary, a gas mixture that exceeds 21% oxygen is defined hyperoxic. Inducing hypoxic condition over the cell cultures is a common experimental technique for the cardiovascular disease studies , for the tumor research [2,3], for the apoptosis [3,4], the gene expression  and for enzyme studies , while the hyperoxic condition is primary induced over the cells for the lung injuries study . A hypercapnic mixture is prepared to vary CO2 concentration instead of O2. Basically, a hypercapnic mixture contains 21% oxygen and an increased amount of CO2 compared with air. Studies conducted over cell cultures in hypercapnic condition have been used for the collection of data about ischemia . A combination of hypoxic and hypercapnic mixtures is also a common mixture configuration in many experiments [9,10].
The MCQ solution.
Both the basic and the advanced CO2 incubator are good instruments for standard cell culture applications but are inadequate when a dynamic gas mixture is required. Moreover neither the basic nor the advanced CO2 incubators allow the control over the amount of O2 in the culture atmosphere. For all those applications that require a dynamic gas mixture preparation and a complete control over the gas mixture composition, MCQ instruments suggests the use of the MCQ Gas Blender 100 Series. This instrument has been appositely designed for the management of 3 components dynamic gas mixtures and has been created to be versatile and adaptable to many lab-applications. MCQ calibrates its instruments with native gases. For cell culture applications the standard configuration is N2 as the balance gas and O2 and CO2 as the solute gases but, under customer’s request, the instrument can be set with other desired non-aggressive gas media. For each channel, MCQ guarantees high accuracy (1.0% of setpoint), high repeatability (0.16% of reading value) and a fast response time for setpoint value change (50ms). Along with the instrument a software for the gas mixture management, the MCQ Gas Mixer Manager, is also provided. The Gas Mixer Manager, manageable with any common desktop or laptop pc, has been designed to allow the user to take a complete control of the instrument and its functions. Easy and intuitive the Gas Mixer Manager allows to start working with dynamic mixtures immediately.