How many bottles of 0.25% digestive juice can be mixed with 1g trypsin powder?

Dissolve 1 g in 400 mL. If only a few mL are used per digestion, it will last a considerable time; however, the laboratory should evaluate the actual consumption rate and contamination risk. The cost of self-prepared solution is usually lower than that of 100 mL ready-to-use, but it requires self-filtration, aliquoting, and quality control, and the time cost and sterility risk should also be taken into account. If weekly usage is several tens of mL or more, self-prepared is more cost-effective; if only occasional passaging or primary isolation is performed, 100 mL ready-to-use is more convenient and more consistent between lots. Primary cell isolation is more sensitive to trypsin activity and purity, and ready-to-use may be more controllable; self-prepared can be used for routine passaging.

0.25% is the mass volume fraction, which is 2.5 mg/mL. 1g=1000 mg， In theory, 400 mL of digestive solution can be prepared. In actual operation, use PBS or HBSS to dilute to 400 mL, do not fill 400 mL first and then add the powder. If you want a regular formula containing EDTA, you can add EDTA to a final concentration of about 0.02% (w/v) or 0.53 mM, dissolve it thoroughly, and filter it with 0.22 µ m for sterilization. Divide into 8 tubes using 50 mL centrifuge tubes. It is recommended to filter and package in a super clean table during preparation to avoid contamination of digestive fluids that may affect primary cells.

The price and delivery time of imported trypsin powder 1g are greatly affected by cold chain and spot inventory. Currently, I do not recommend giving a specific quotation. I suggest directly inquiring with the local agent and confirming whether it is of cell culture grade, whether it contains EDTA, and whether there is endotoxin data. The delivery time for imported big brands may be 2-4 weeks, while domestic substitutes generally arrive faster, but digestion efficiency and cell viability tests must be conducted. If it is only routine adherent cell passage, the risk of domestic legitimate sources is not high; If it is a precious primary cell, it is recommended to compare it with small packaging and cells from the same batch first. Pay attention to the batch number during procurement to avoid frequent changes that may affect digestion conditions.

Aliquot 50 mL/tube and store at -20°C; most aliquots remain usable within six months, but repeated freeze-thaw cycles reduce trypsin activity, which has a particularly significant impact on operations sensitive to enzyme activity, such as primary cell isolation. It is recommended not to repeatedly freeze and thaw the same tube; instead, aliquot into 5–15 mL/tube according to single-use volume, with no more than 1–2 freeze-thaw cycles. After thawing, it can be stored short-term at 4°C for 1–2 weeks, but if turbidity, precipitation, or obvious pH changes occur, do not use it for critical experiments. Before use, prewarm at 37°C and avoid prolonged placement at room temperature.