My fetal bovine serum contains flocculent precipitates, what is it?

Serum precipitation occurs for a number of reasons, the most common being the denaturation of lipoproteins in the serum. The presence of fibrin in serum is one of the main causes of precipitation after thawing. However, these flocculation precipitates do not affect the quality of the serum itself, if you want to remove these precipitates, the serum can be subpacked into a sterile centrifuge tube, slightly centrifuged at 400g, and the supernatant can be added to the medium and filtered together.

How to preserve serum?

The serum should be kept at -5 ° C to -20 ° C and not for more than one month at 4 ° C. If you are unable to use one bottle at a time, it is recommended that you sterile subpack and then return to freezing.

How do I defrost the serum?

After the serum is removed from the freezer, it is recommended that you thaw it in the refrigerator at 2-8℃ overnight, and then melt it at room temperature. The thawing process requires regular shaking and mixing. Use immediately once defrosted.

How do I know if my cells need heat-inactivated serum?

Most insect cell lines and embryonic stem cell lines require heat-inactivated serums. You can also consult the cell supplier to obtain the corresponding cell culture requirements.

Why the heat-inactivated serum? Is heat inactivation necessary?

Antipyretic can inactivate the complement system. The use of heat-inactivated serums is recommended in immunological studies, cultures of ES cells, insect cells, and smooth muscle cells. Experiments have also shown that heat inactivation is not necessary for most cells. The serum treated by this treatment has only a small promotion of cell growth, or no effect at all, but the high temperature treatment will affect the quality of the serum, and even cause a decrease in the rate of cell growth. Heat inactivated serum, precipitates will increase significantly, these precipitates under the inverted microscope observation like "small black dots", so that researchers mistakenly think that the serum is contaminated, and the serum at 37° conditions will increase the sediment, so that researchers mistakenly think that it is the proliferation of microorganisms. Therefore, it is recommended that you do not do heat treatment unless necessary! This not only saves your precious time, but also ensures the quality of the serum!

If the serum I get is partially thawed, can I still use it?

All serum is kept in dry ice during transport and you should get a frozen product. If the serum is partially thawed, it can continue to be used, but at least two-thirds should remain frozen.

How do I preserve my antibodies?

Antibody storage containers should be made of materials that do not adsorb proteins, such as polypropylene, polycarbonate and borosilicate glass. If the protein concentration of the stored antibody is very low (10-100 mg /L), an additional isolation protein should be added to reduce the adsorption of the antibody protein to the container, and the isolation protein is usually 0.1% to 1.0% bovine serum albumin.

Most of the antibodies that have been diluted should be kept at 4℃-8℃ to avoid harmful effects of freezing and thawing on antibody proteins. The antibody stock solution and the isolated immunoglobulin components should be kept at -20℃ and repeated freeze-thaw should be avoided. Frozen antibody solutions should be thawed slowly at room temperature, and rapid thawing at high temperatures should definitely be avoided.

Antibodies contaminated with bacteria often produce false positive results, and the contaminated antibody solution and other reagents should be discarded. To prevent bacterial contamination, 0.01% sodium azide can be added to the antibody solution. After vacuum freeze-drying, the antibody can be stored for 3-5 years below -20℃.

Dilute monoclonal antibody should be preserved with 0.1% sodium azide concentration. Most diluted antibodies can be cryopreserved, and a few antibodies may lose antigenic activity. Most monoantibodies, provided the protein concentration is appropriate, can be stored at 4 ° C for several months.

How do I choose the homotype?

Homologous controls were used to confirm that primary antibody binding was specific and not the result of non-specific Fc receptor binding or other protein interactions. Homologous control antibodies should be matched with the same host species, homologous type, and conjugate. For example, if the primary antibody is FITC-coupled mouse IgG1, then FITC-coupled mouse IgG1 homotype control needs to be selected.

What is CD antigen?

CD, or clusters of differentiation. At the Nomenclature Committee of the IV International Conference on Immunology (Kyoto, 1983), this antigen was named CD antigen based on the clustering of differentiation antigens on the surface of T cells. CD antigen not only exists in T cells, but also in B cells, macrophages and so on.

Comparison of characteristics of monoclonal antibodies (McAb) and serum antibodies for routine immunization

item

Routine immune serum antibodies

McAb

Antibody-producing cell

polyclonality

monoclonal

The binding force of the antibody

Specific recognition of multiple antigenic determinants

Specific recognition of a single antigenic determinant

Immunoglobulins category and subcategory

Heterogeneity, mixed texture

Same genus, pure texture

Specificity and affinity

It varies from batch to batch

High specificity, uniform antibody

Effective antibody content

0.01 ~ 0.1mg/ml (mouse ascites)

0.5 ~ 5.0mg/ml(mouse ascites)

0.5 ~ 10.0μg/ml (culture supernatant)

For routine immunological experiments

usable

Monoclonal antibody in combination

Antigen-antibody lattice formation (precipitation reaction)

Easy to form

Generally difficult to form

Antigen-antibody reaction

Antibodies are mixed, forming a 2-molecule reaction is difficult and irreversible

Can form 2 molecular reaction, reversible

There is a significant difference in the color of the double antibody solution purchased before and after two times, is it a product quality problem?

The color difference is mainly caused by the difference of raw material batches, and the color difference will not affect the use of the product. Foreign countries have also issued a special document on this issue, if necessary, you can contact our sales to obtain.

How do you isolate and purify nucleic acids?

Nucleic acids exist in a variety of cells, such as viruses, bacteria, parasites, plant and animal cells; In a variety of specimens, such as blood, tissue, saliva, urine and other sources of specimens. Therefore, the separation methods are complex and varied. Due to the differences in the abundance of various DNA and RNA, various analysis methods have different requirements for the purity and amount of nucleic acid, so the method should be understood and selected before the experiment. In general, the separation and purification of nucleic acid is based on lysate cells, the use of phenol and other organic solvents extraction (nucleic acid dissolved in buffer, that is, water phase), separation, purification; Ethanol, acetone and other organic solvent precipitation, harvest. The methods used to dissolve cells vary with different specimens, such as SDS plus NaOH, protease, or ultrasonic crushing, etc. Phenol extraction mainly denatured proteins and precipitate them in the organic phase, while nucleic acids were retained in the aqueous phase to achieve the purpose of separating nucleic acids. Proteins are the most abundant in experimental biological specimens. In order to remove the residual organic solvent in the separation process, the common method is to add cold ethanol and salt to precipitate nucleic acid, recover nucleic acid by centrifugation, and then wash precipitation with 70%-80% ethanol to remove excess salt, so as not to affect the dissolution of nucleic acid and inhibit the enzymatic reaction in subsequent steps. In order to obtain pure nucleic acid, protein can be removed by protease, RNA can be removed by RNA enzyme, pure DNA can be obtained, DNA can be removed by DNA enzyme and RNA can be obtained. At present, many commercial nucleic acid separation columns have been developed, which can simply and quickly isolate DNA or RNA with high purity. Some of its separation principles use the molecular weight difference of nucleic acid, and some use the characteristics of nucleic acid to be separated and its specific combination to achieve the purpose of separation and recovery.

The color difference between different batches of purchased phenol-containing red pancreatic enzymes or part of the product turns yellow, is it a quality problem, can it continue to be used?

The yellow color may be caused by the uneven distribution of phenol red in the frozen storage process, which generally does not affect the performance of the product. The product is slowly cooled in the process of frozen storage, because the cooling rate between different bottles is not completely consistent, and the different components in the bottle can be solidified at different temperatures, resulting in different colors, which will not affect the use.

Is there a product qualification certificate or quality inspection certificate?

According to the product number and batch number, each batch of products has the corresponding COA inspection form, if necessary, you can contact the corresponding sales staff to obtain the COA of the product.

What is the shelf life of the product?

The shelf life or validity period of different products is different, if necessary, please contact us.

How do I get my invoice after ordering a product?

After you receive the goods, our finance staff will issue an electronic invoice for you.