How to Check if the Filter Membrane is Qualified?

1. Perform integrity test before filtration: This method requires the use of a syringe filter, first soaking the filter membrane with liquid, and then using a syringe to blow air to the filter. If the air cannot pass through the filter, the filter membrane is good.

2. If the filtration culture medium uses a large filter membrane, it is not feasible to perform the above-mentioned integrity test before filtration, and it can only be observed by the naked eye. Therefore, it is very important to do the post-filtration integrity test. The specific method is:

(1) After the filtrate is filtered, slowly open the filter to see if it has any problems such as cracks and small holes.
(2) Aspirate a small amount of culture medium for the test. A small amount (2 ~ 5ml) of the culture solution is added to the small culture flask, cultured in the incubator, 24 to 48 hours without turbidity, air bubbles, can be used with confidence; or a small amount of culture medium for cell culture, 24 hours of good cell growth, indicating that this culture solution is no problem, and you can use it with confidence. There is no problem with the culture solution, indicating that the filter membrane is qualified, and the contamination during cell culture is greatly reduced.