细胞污染,中洪博元 z-bo 2020-07-20 1389

 What are the methods to prevent and control cell contamination?

      Regardless of whether you are a newcomer or a familiar hand, cell contamination must be faced. For cell contamination, I think the best measure is to prevent it, because once the cell is contaminated, it is very difficult to save it. It will be much worse. Therefore, Zhonghong Boyuan will do some pollution prevention methods with them.

       First of all, all things entering the safety cabinet must be disinfected with 75% alcohol before entering. Special attention should be paid to our hands. As long as they leave the safety cabinet, they must be disinfected with 75% alcohol before entering the safety cabinet. Experiment consumables should be placed in a suitable container, wrapped in newspaper, and then sterilized. Other irregular consumables can be placed in an aluminum lunch box because the sterilization may not be able to remove the possible adhesion of grease or other impurities.

Secondly, the things in the safety cabinet should be placed in an orderly manner. This can be determined according to personal use habits (if you are using a public safety cabinet, you may need to temporarily adjust it before use). Take Zhonghong’s experiment as an example. Put the *head box (all specifications are available) on the right, the reagents to be used in the experiment on the right, and the waste tank on the left, and ensure a certain safety distance from the reagents. Place the petri dish in the right corner and other consumables in the left corner. (Such as test tubes, etc.), try to ensure that the most commonly used things are placed on the right hand side (the opposite for left-handed friends), and the second frequently used things are placed on the left hand side (the opposite for left-handed friends), the right operation area is the clean area, and the left is the unclean area ( Such as waste liquid tank and other leftover materials).

Thirdly, since the hands and forearms need to enter the safety cabinet during the use of the safety cabinet, friends with conditions should prepare at least one piece of special clean suit for the cell room (put it into a cloth bag for disinfection and dry it in the cell room. Take it out and don’t go out of the cell room unless it is replaced. Friends who are unqualified should prepare at least a pair of sleeves and put them in a safety cabinet for UV disinfection after each use.

　　Cell culture is inseparable from various reagents and consumables, such as culture media, serum, cell dishes/bottles, etc., so the second step to prevent cell contamination is to properly handle and use these reagents and consumables. If laboratory conditions permit, the safest thing is to buy commercial reagents and consumables directly, such as Gibco, Hyclone, ScienCell reagents, Eppendorf, Corning consumables, etc. As long as these brands of reagents and consumables are genuine, they are of no quality problem. If you need to buy a dry powder to prepare reagents yourself, then the aseptic operation in reagent preparation is also extremely important. In addition, it is recommended that the amount of reagent preparation should not be too much each time. For example, the medium should be used up within 1-2 weeks. When it is divided into vials, you can consider filtering it with a syringe filter again to reduce the possibility of bacterial contamination.

　　 After all the preparations are in place, everyone needs to pay attention to the processing of cells. Before cell processing, all reagents and consumables needed for the current experiment should be prepared to minimize the walking back and forth during cell processing. Before using the safety cabinet, it is best to sterilize by ultraviolet irradiation for 30 minutes, and then ventilate for 5 minutes to ensure proper ventilation. During the experiment, it is best to cover all the reagents with the caps when they are not used. If you need to open the caps, do not pass over the mouth of the bottle except for the clean head to prevent reagent contamination. If a petri dish is used for cell culture, it is best not to open the lid of the dish for a long time. In addition, pipettes are also a hidden way of cell contamination, especially those who use non-filter* heads. When drawing reagents, it is easy to accidentally pour the reagents into the pipette. If this happens, use alcohol in time. The cotton ball wipes off the sucked reagent, especially the culture medium, which can easily become a breeding ground for bacteria. A contaminated pipette can easily contaminate all the cells of the station, or even the cells of the entire laboratory, so it is recommended that qualified station friends must use a filter head when handling cells. Of course, even if you use a *head with a filter element, you should try to avoid reagent sucking, because it is very difficult to completely remove the reagent sucked into the pipette.

　　 Incubators, as a place for cell culture, also need to be careful. Because the temperature and humidity in the incubator are very high, it is very suitable for bacterial growth, so if there are conditions (the laboratory has 2 or more incubators), it is best to wipe the incubator with 75% alcohol regularly, and replace the incubator regularly in time Inner sink.

　　Early contamination is the deterioration of the cell condition, but it can still maintain growth. No obvious microorganisms or a small amount of microorganisms can be seen under the microscope (light microscope). At this time, we recommend washing with PBS for several times when changing the liquid, and then adding suitable antibiotics. As long as early pollution is discovered in a timely manner and handled properly, there is still a great possibility of rescue. Late pollution is a significant change in cell morphology, the cells stop growing, and microbes can be seen under the microscope. At this time, Zhonghong recommends that you clean up the relevant cells in time to avoid contaminating other cells, and resuscitate earlier batches of cells. Therefore, you will find that after receiving new cells, you should not rush to carry out the experiment. Instead, you should carefully cultivate and freeze 1 or 2 batches of early cells, and then carry out the experiment, so that if there is a problem with the experimental cells, you can have a stock The cell guarantees that the experiment can continue.