3 High-Efficiency Tips for Cell Culture Media Filtration

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Filtration is an important step when preparing cell culture media, its main purpose is to remove microorganisms, cell debris and other particulate contaminants that may be present.

Traditional clarification and filtration methods consider using gauze to intercept particulate impurities or high-pressure steam sterilization.

However, culture media containing macromolecule nutrients such as proteins may cause protein denaturation after high-pressure sterilization, thereby destroying the active ingredients.

This article introduces 3 efficient methods of media filtration, and provides an in-depth analysis of what needs to be paid attention to during filtration.

Why Does Culture Media Need To Be Filtered

Why Does Culture Media Need To Be Filtered

During the preparation of culture media, there are impurities and microorganisms that cannot be removed by ordinary sterilization. Here are some of the main reasons to filter cell culture media.

Microbial Contamination Prevention

Cell culture requires sterile conditions because the presence of microorganisms may cause cell infection and affect experimental results. Through filtration, harmful microorganisms such as microorganisms, bacteria and fungi can be effectively removed from the air.

By employing filtration methods, laboratories can create and maintain a controlled environment where the risk of microbial intrusion is significantly minimized.

This preventive measure not only protects the health and vitality of the cultured cells but also upholds the scientific rigor and accuracy of experimental outcomes in cell culture studies.

Remove Particles And Cell Debris

Particles and cell debris present in culture media can exert detrimental effects on cell culture systems. These contaminants have the potential to interfere with experimental results, compromise cell health, and impede proper cell growth.

Inconsistent cell culture conditions can lead to skewed findings and hinder the reproducibility of experiments, making the removal of particles and cell debris a crucial aspect of maintaining a high-quality cell culture environment.

Filtration effectively removes these particles and debris, ensuring the purity of the culture medium.

Improve Culture Medium Transparency

Improve Culture Medium Transparency

In cell culture research, improving the transparency of the culture medium through filtration is instrumental for precise microscopic observation.

A clear culture medium enhances the contrast and clarity of cell images under the microscope, allowing researchers to more accurately assess cell shape, structure, and activity. Transparent culture media contribute to obtaining reliable data and results in cell biology studies.

Filtration also helps improve the clarity of the culture medium. This is critical for observing cell growth and performing microscopy, as clear media better supports observation of cells.

3 High-Efficiency Tips for Cell Culture Media Filtration

Some of the conventional methods of media filtration that we would normally use are inefficient and in some cases costly, this section will delve into three key techniques aimed at improving the efficiency of cell culture media filtration.

By exploring these strategies, we aim to shed light on how these practices can significantly enhance the outcomes of cell culture research and bioprocessing applications.

Use high-flux filters instead of gauze

The culture medium often appears sediment or turbid after preparation and needs to be filtered to make it clear and transparent before use. When performing coarse filtration, you can consider using gauze to intercept particulate impurities.

The first is liquid culture medium: use filter paper to filter to ensure that the culture medium is clear. Egg whites diluted with water can be added and filtered after heat treatment to remove insoluble materials.

The second is solid culture medium (such as agar culture medium): after heating and melting, filter it through flannel or absorbent cotton sandwiched between two layers of gauze while it is still hot.

Using the natural precipitation method, after melting with high-pressure steam, let it stand overnight to remove the sediment at the bottom, and then melt it again to obtain a clear agar medium.

The above two are common clarification operations, but if higher precision is required, polypropylene (PP) filters or glass fiber membrane pleated filter elements can also be used.

The filter elements of these two membrane materials have extremely high sodium content. The pollution capacity and interception rate, high throughput, can not only quickly intercept impurity particles and small microorganisms, but also speed up the filtration speed and improve the filtration quality.

When encountering a large number of culture media, using polypropylene filters can be effective Reduce filtering time.

Dual Filter Elements For Pre-Filtration: Optimize Culture Medium Purification And Extend Filter Element Life

Prefiltration is a critical step during media preparation, especially before downstream purification. This step is designed to remove colloids, aggregates, non-target proteins, lipids, and particles while protecting the downstream sterile filter.

This process is often called sterile filtration and is an important protective step before final filtration. Using a filter element within 1 μm is a common choice, and adding a filter element of about 2 μm before the 1 μm filter element can further improve the effect.

Two Filter Elements

Why Do We Need Two Filter Elements With Different Precisions?

The composition of different culture media varies greatly, especially for culture media rich in proteins, sugars and other macromolecules. Using a single-precision filter element may face two main problems:

Obstruction of filtration flow: The presence of large molecules may cause the filter element to be clogged quickly, reducing filtration efficiency, and even affecting subsequent steps.

The life of the terminal sterilization filter element is short: The precipitation of macromolecules can easily clog the filter element, greatly reducing its lifespan and increasing the need for more frequent filter element replacement.

Advantages of multi-stage gradient filtering

By using multi-stage gradient filtration, even using two filter elements with different precisions, the following advantages can be obtained:

Ensure filtration flow: The combination of filter elements with different precisions can more effectively remove various impurities, maintain the clarity of the culture medium, and help maintain appropriate filtration flow.

Extend the life of the terminal sterilization filter element: The lower precision filter element is responsible for removing macromolecular impurities, effectively reducing the burden on the terminal sterilization filter element, extending its service life, and reducing maintenance costs.

High-Pressure Sterilization

Use Membrane Pleated Filter Elements Instead Of High-Pressure Sterilization

There are two main methods for sterilizing culture media, high-pressure sterilization and filter sterilization.

Compared with filtration, high-pressure sterilization has less work intensity and lower cost, but it is easy to cause the loss of nutrients, and it is easy to add samples (sterile glutamine solution, sterile sodium bicarbonate solution, etc.) during multiple additions. Cause secondary pollution.

Medium-containing macromolecule nutrients such as protein may denature the protein after high-pressure sterilization, thereby destroying the active ingredients.

To ensure the stability of the medium components, sterilization and mycoplasma removal must be performed through filtration.

Most culture media usually use filter membranes with pore sizes of 0.22 μm and below for filtration sterilization, and this has become the development direction of culture medium sterilization.

It can ensure that the finished product is free of bacteria and mycoplasma and minimizes the nutrient loss of the culture medium.


The preparation of cell culture media is a crucial step in bioprocesses such as microbial fermentation and cell culture. Maintaining the sterility of the culture medium is crucial to the success of the entire bioprocess, and filtration, as a key step in culture medium preparation, is an indispensable part of ensuring the quality of the culture medium.

These three efficient methods not only ensure the clarity and purity of the culture medium, but also improve the filtration efficiency, extend the life of the filter element, reduce production costs, and provide new opportunities for cell culture and microorganisms.

While you pursue culture media clarity, purity and efficiency, we provide you with professional solutions. Please contact us and let us work together to provide high-quality technical services for your research and production.

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