Is it scientific to select fetal bovine serum suppliers based on the global ranking of biological reagent companies?

Beyond brand rankings, actual procurement should focus more on supply stability, whether specific lots can be reserved, cold-chain transportation temperature records, and whether there is local stock in China. You can simultaneously ask sales representatives from BI, Sigma, and other brands to send trial samples, and clarify whether they support try-before-you-buy and returns or exchanges for unopened products. After arrival, inspect the bottles first for leaks, check whether the color is clear, and look for precipitates, and record the lot number. Request virus testing reports from the supplier, pay attention to whether endotoxin, hemoglobin, and other levels match your cell type, and then decide whether to make a bulk purchase.

Both Biological Industries and Sigma sera are widely used in many laboratories, but when selecting, it is essential to clarify the source and grade. BI has many models, so it is necessary to confirm whether the source is Australian, South American, or New Zealand, and whether it has undergone screening for tetracycline, hemoglobin, etc.; Sigma serum batch quality is generally relatively stable, but lead time and price need to be confirmed separately. 293T is more sensitive to serum, so it is recommended to prioritize premium fetal bovine serum or low-endotoxin grade, and require a COA to be provided. HeLa is relatively robust, but after changing serum, adherence and morphology should still be continuously observed for several passages.

Serum cannot be solely based on brand ranking, batch differences have a greater impact on cell status than brand differences. We previously used Gibco Australian sources because of their relatively stable inter batch conditions, but we have tried BI and Sigma for long lead times, so we suggest starting with small samples. We suggest that after receiving the trial package, you test for endotoxins, hemoglobin, appearance, pH, and osmotic pressure, and use your Hela and 293T to create growth curves, doubling times, and adhesion morphology. Buying a quantity of six months to a year at once and locking it with the same batch number can determine the ranking based on the company's size and source of goods, but it cannot replace actual batch inspection.

When the inventory is approaching its bottom, do not wait for the stock to run out before making a last-minute replacement. After the arrival of the new serum, it is recommended to first mix it with the old serum in a 1:1 ratio for 2 to 3 passages, and then gradually transition to the new serum, focusing on observing the 293T transfection efficiency, Hela adhesion, and proliferation. If cells become round, vacuoles, slow proliferation or abnormal morphology occur, the batch may not be suitable, and unopened bottles should be returned or exchanged in a timely manner. A weekly volume of around 50 mL is not particularly large, but it is recommended to prepare at least two different batches. Do not eliminate the old batch until the new batch is validated and keep one bottle as a minimum.