During cell culture, microbial contamination is the main cause of cell culture failure. Therefore, the cell culture environment, equipment, media and other materials must be kept sterile. The medium used in the cell culture process, as well as the sterilization of the reagents that are easily destroyed by heat, must be sterilized by filtering through a microporous filter. This device, which is equipped with a microporous membrane to sterilize, becomes a filter.
How filters work?
Microporous filter membrane is a kind of high molecular membrane filter material. There are many micropores on it. The pore size ranges from 0.025um to 14um. The area of membrane pores accounts for 80% of the entire area. It is mainly used for filtration of aqueous solutions. According to the size of the microorganism, filter membranes with different pore sizes are selected. Most microorganisms are micron-sized, so microporous membranes can isolate most bacteria. The advantage of this method is that it can not destroy the chemical components of various substances in the solution, and is suitable for the filtration of enzymes, nucleic acids, serum and other active molecules. However, due to the limited filtration capacity, it is only suitable for a small amount of solution.
In the process of cell culture, all-glass microporous membrane filters are mainly used, including: a set of sand core filter devices (dust cover, cylindrical glass funnel, conical flask, sand core filter, microporous membrane, aluminum alloy clip ) And one oil-free vacuum pump. The complete set is connected using standard interfaces.
Dust cover: prevents dust or magazines from entering the solution during filtering.
Cylindrical glass funnel: high-quality glass material, no bubbles, commonly used specifications are 250ml
Standard mouth sand core filter: ultra-hard glass material, no air bubbles, fast flow, pressure resistance, good sealing. Available for autoclaving.
Triangular bottle: good sealing, commonly used size is 1000ml
Microporous membrane: There are many different types of materials, with different specifications of pore size of 0.025-14um.
Aluminum alloy clip: Fix the sand core filter device and connect it with the cylindrical glass funnel.
Oil-free vacuum pump: provides a completely clean vacuum environment, and the pump itself does not generate any pollutants.
Operation method of all-glass microporous membrane filter
- Autoclave the microporous membrane and sand filter.
- In a sterile environment, install the microporous membrane into the sand core filtration device, and connect it to an oil-free vacuum pump.
- Vacuum filter the microporous membrane slightly before suction filtration to make it fit tightly with the filtering device.
- Turn on vacuum filtration and introduce the solution to be filtered into the cylindrical glass funnel.
- At the end of the filtration, first disconnect the vacuum pump and close the vacuum pump switch.
- Pour the filtrate into a sterile container.
- There are two types of microporous membranes: hydrophilic and hydrophobic. The material of the membrane depends on the nature of the filter liquid.
- The filtration and sterilization are generally performed on a clean bench. The pore size of the filter membrane is generally 0.22um or 0.45um.
- Tighten the filter when filtering to prevent outflow
- Filtration should be laborious. If it feels easy, the filter membrane is broken.
- The 0.45um filter is generally used for the first time of two filtrations to prevent the 0.22um filter from clogging.