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Q：What is the efficiency and toxicity of the transfection reagent?
Some cells, such as 293T and Hela, have high transfection efficiency, and cationic polymer transfection reagents have little cytotoxicity to cells and can be metabolized as cells grow, transfection efficiency was further improved.
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Q：What is the difference between fetal bovine serum and other bovine serum?
1. Serum is a complex mixture, which is produced by removing fibrin from plasma, and provides various kinds of support and protection for cell culture and growth. 2. Fetal bovine serum was taken from fetal cows delivered by caesarean section; newborn bovine serum was taken from newborn cows within 24 hours of birth; calf serum was taken from calves born between 10 and 30 days of age. Because fetal bovine serum has not been exposed to the outside world, fetal bovine serum contains harmful components such as antibodies and complement is the least, so its quality is better than other types of bovine serum.
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Q：What are the main roles of serum in cell culture?
Provide hormones that maintain cell index growth, nutrients that are absent or minimal in basic media, and major low-molecular-weight nutrients. 2, provide binding protein, can recognize vitamins, lipids, metals and other hormones, can bind to or adjust the vitality of the substances they bind. 3. In some cases, binding proteins can bind to toxic metals and pyrogen and play a role in detoxification. 4, is the cell adheres to the wall, spreads on the plastic culture medium the necessary factor source. 5. Acting as ph buffer. Provide Protease inhibitor that inactivate the remaining trypsin during cell passage and protect the cell from damage.
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Q：What is Annexin V/PI assay?
The Annexin V/PI assay is used to distinguish early apoptotic cells through Annexin V labeling and necrotic/dead cells through propiconazole (PI) labeling. In the early stage of apoptosis, the cell membrane begins to lose asymmetry, leading to the translocation of phosphatidylserine (PS) to the outer surface of the membrane, where it can be detected by annexin V conjugates. However, in the case of membrane rupture, such as necrosis, annexin V conjugates can enter and bind to PS residues in the inner membrane, leading to false positive results. Therefore, it is recommended to use non membrane penetrating nuclear dyes (such as PI) in combination with annexin V conjugates. This allows users to distinguish between early apoptotic cells (Annexin V staining), late apoptotic cells (Annexin V and PI staining), and necrotic cells (PI staining only).
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Q：What is the difference between Annexin V and TUNEL?
Terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) is a staining method used to identify DNA fragmentation sites within cells - a hallmark feature of late stage cell apoptosis. It uses enzyme terminal deoxynucleotide transferase (TdT) to connect modified dNTPs (such as dUTP) to the 3 '- hydroxyl end of fragmented DNA strands. DNTPs are typically modified with fluorescent groups to facilitate quantification and/or visualization.
Annexin V staining identifies the early stages of cell apoptosis by binding to PS residues exposed outside the cell due to loss of membrane asymmetry. Annexin V is commonly labeled with fluorescent groups such as FITC to promote the detection of apoptotic cells.
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Q：Is the cell reactive oxygen species detection experiment applicable to all types of cells?
Cell reactive oxygen species detection experiments are typically applicable to most types of cells, including mammalian cells and microorganisms. However, different types of cells may have differences in the production and treatment of reactive oxygen species, so optimization and validation should be carried out for different types of cells when conducting experiments.
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Q：How to choose appropriate reactive oxygen species detection reagents?
When selecting reactive oxygen species detection reagents, factors such as cell type, experimental objectives, and detection methods should be considered. DCFH-DA is suitable for fluorescence microscopy observation, while ROS Glo reagent is suitable for flow cytometry analysis. Select appropriate reagents according to experimental requirements.
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Q：Can liquid culture media be stored at -20 ℃?
may not! Because at -20 ℃, salts in the culture medium are prone to precipitation. After the culture medium melts, some salts may not be able to dissolve again, resulting in a decrease in osmotic pressure of the culture medium. When cultivating cells, they are prone to rupture and death.
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Q：What is the difference between serum-free culture medium and regular culture medium?
Serum-free culture mediumIt is a synthetic culture medium that can maintain cell growth without the need for serum, and may contain small or large amounts of protein components.Ordinary culture mediumIt is usually necessary to add fetal bovine serum or other animal serum to promote cell growth.
The basic components of serum-free culture medium include basic culture medium and added components such as fibronectin, insulin, transferrin, etc., which are used to maintain the nutrients and factors required for cell growth.
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Q：How long can fetal bovine serum be stored at 4 ℃?
Fetal bovine serum can generally be stored for 6-12 months at 4 ℃. But this is not absolute, the actual storage time will be affected by various factors, including the quality of the serum, the sealing of the container, the stability of the refrigerator, etc. To ensure the quality of the serum, it is recommended to use it within 3 months after purchase. If long-term storage is required, it is best to freeze it at -20 ℃ or lower, which can last for 1-2 years or even longer. However, please note that repeated freezing and thawing should be avoided during each use to prevent loss of protein and nutrients. Before use, carefully read the product manual and follow the supplier's recommendations for operation.
"Heyuan Liji" is a joint venture between Heyuan Biotechnology (stock code: 688238) and Liji Biotechnology, specializing in the "Liji Biotechnology" and "Life-ilab" reagent brands
