Before describing the product differences, a brief description of the mesenchymal stem cell serum-free medium is described.

How is the serum-free medium of mesenchymal stem cells developed?
Researchers According to recent decades, researchers in China and abroad have made some achievements in mesenchymal stem cell research, such as what kind of substances can promote stem cell growth and what substances can inhibit mesenchymal stem cells. Differentiation, what kind of substance has a better adherence effect, and so on.
Based on this, a preliminary mesenchymal stem cell serum-free medium formulation was developed.
Then, the corresponding mathematical model is constructed, combined with a large number of experiments, to determine the optimal ratio of various component combinations.
Finally, by applying human tissue (umbilical cord or fat) from different sources, extracting and culturing mesenchymal stem cells, fine-tuning the product formula, the medium can be more widely applied to the extraction of tissue mesenchymal stem cells from different sources of human body and to cultivate.
In a word, it is a culture product for mesenchymal stem cells that has been specially developed based on people's understanding of stem cells.

What is the condition of serum medium?
Generally use DMEM/F12, or a-MEM, plus fetal bovine serum.
In a word, it is a naturally formed product that cannot be adjusted and optimized according to the characteristics of stem cells.

What is the difference between serum-free MSC medium and serum MSC medium?
In the big picture, there are roughly nine different aspects.

1. In terms of safety of use <br> Serum-free MSC medium is safer.
The medium was not supplemented with serum, nor was it added with any animal-derived components, chemically defined. Therefore, the medium does not have any animal-derived components, and the cells cultured in the serum-free medium of the mesenchymal stem cells do not cause allergic and fever symptoms frequently caused by human immunological rejection after entering the human body.
In addition, since there are no components derived from animals, naturally there are no pathogenic bacteria or viruses associated with them, such as mad cow virus.

2. In terms of ease of use
It's more convenient and requires fewer steps.
The MSCs can be cultured in a serum-free medium with a friend's mesenchymal stem cell. The stem cells can be digested with mild digestive enzymes (also defined by chemical components, no animal-derived components), and do not need to be digested after digestion (traditional practice generally uses serum medium). Or the serum is terminated, and it can be removed by direct dilution with PBS.
Less operation means less work and a lower probability of contamination.

3. From the perspective of stem cell production
The yield (amplification factor) of MSC is higher than that of serum.
The amount of stem cells obtained by culturing in MSC medium depends not only on the nutrient components that the medium can provide, but also on whether the cells differentiate.
MSC serum-free medium makes full use of scientific research results in recent years, especially the research on stem cell differentiation and aging mechanism, and can better inhibit cell differentiation through component adjustment.
In terms of the number of cells, generally a 20CM umbilical cord can obtain 1E7 of primary cells. The amplification ratios of the first three generations were all more than 10 times. (Inoculation density 8000 cells/cm2).

The serum medium, because it is derived from animal blood, has both a component that inhibits stem cell differentiation and a component that promotes stem cell differentiation, and there is no way to manually select it.
For example, the serum contains glucose, together with the sugar in the medium, the total content is higher, the high concentration of sugar is easy to promote aging and differentiation; in addition, the serum generally contains exosomes, which is a kind of vesicle secreted by the cells. Structure, which contains substances that regulate cell growth and differentiation. The ratio of these substances in different serums is different, so it is easy to cause differentiation; serum contains metabolic waste, which is generally harmful to cells and easily leads to aging and differentiation.
In addition, many users currently use a medium with phenol red, and phenol red is a common hormone component, which has obvious differentiation and differentiation effects on stem cell growth.

In fact, the high yield of cells using serum-free MSC medium is the main reason for the current Chinese customers to switch to serum-free medium. Not security.

4. In terms of cell quality (morphology, activity, dryness and phenotype)
From the microscope, the stem cells of serum-free MSC culture were short in shape and showed a standard three-dimensional fusiform shape, and the cell edges were clear and translucent. This is a visual representation of the less aging and differentiation of cells.
In contrast, MSC cells cultured in serum medium have a flat cell shape, a larger volume, and an unclear edge.
The serum medium is complex in composition and contains many substances that promote differentiation. The cells are prone to spontaneous differentiation, and the cells lose their dryness. In addition, when directed differentiation in vitro, it is easy to have residual media, which may interfere with directed differentiation.
However, the serum-free medium formula is clear, the amount of each substance is certain, and there is no interference component. The cells are not easy to spontaneously differentiate, and the dryness is maintained well. Even if there is residue, it will not interfere with the directed differentiation.
The phenotype of MSC serum-free medium is more in line with the definition of MSC cells.

5. In terms of cost of use<br> Using MSC serum-free medium, the cost tends to be lower and lower.
Serum-free medium, each of which is synthetically synthesized. Including amino acids, inorganic salts, recombinant proteins, and the like. As technology advances and capacity expands, the production costs of all manufactured components will drop significantly.
In particular, as media research and development companies continue to improve their products, such as through formulation optimization, the use of expensive recombinant proteins is continuously reduced, and stem cell culture media are gradually developing toward fully chemically defined media (CD media), CD culture. The base does not contain expensive recombinant proteins, and the cost will naturally drop dramatically.
From the user's point of view, especially for stem cell drug companies, the choice of serum medium or serum-free medium is the choice of the core production process. Once selected, it is extremely difficult to change in the future. Therefore, they are more inclined to choose a serum-free medium that will become less and less expensive in the future.

6. From the perspective of stem cell drug declarations <br> Since serum-free media has a clear product formula, the regulatory requirements for the safety of cell-retaining media components are very easy to accomplish.
Due to the serum medium, there are more than 150 known components in serum, and there are many unknown components. The safety verification of the medium residue in the cell preparation is extremely difficult to complete, if not impossible.

7. From the perspective of controlling stem cell secretion factors <br> The serum-free medium is artificially added because all components are artificially added. Therefore, it is convenient to adjust the content of proteins secreted by stem cells by adjusting some components. For example, PEG2 secreted by stem cells, MSC serum-free medium can greatly improve the expression of PEG2 by adjusting the contrast of different components. Of course, other expression levels of secreted cytokines involved in stem cell preparations can be achieved by adjustment of the MSC serum-free medium formulation.

8. From the perspective of cell aging <br> Serum-free media will of course not add substances that will accelerate cell aging.
The serum components in the serum medium are complex, with more than 150 known component components and multiple unknown components. Some of these components are beneficial for cell growth, some have no effect on cell growth, and some are detrimental to cell growth. Studies have shown that MSCs induced by hydrogen peroxide have aging characteristics. When cultured in vitro, these reactive oxygen species (ROS) damage cells by oxidizing biological macromolecules such as DNA and proteins, and accelerate cell senescence. Stem cells are particularly sensitive to the accumulation of ROS in the microenvironment, and serum contains ROS, which may lead to a large accumulation of ROS in the cells and cause stress-induced premature senescence in the cells.

9. In terms of performance stability <br> The serum-free medium has a clear formulation, so the difference between batches is extremely small, almost no.
While the serum comes from different individuals, the various components in the serum vary greatly due to the different constitution of the cattle. For example, EGF in serum, some content is 10ug / ml, and some are only 2ug / ml, a difference of 5 times. Batches between different brands and even branded products may vary greatly. The training effect is not guaranteed.