Friends who do cell -related experiments must often use cell freezing methods. In short, cell frozen storage is to save cells in a low temperature environment to achieve the purpose of long -term preservation. Cells will have a certain degree of mutation during the transmission process. In order to ensure that the cells can still be used in the case of cell pollution and mutation, some cells are usually used for freezing.
The principle of cell frozen
One principle in the process of cell frozen and recovery is "slow frozen fusion" to save the vitality of cells to the maximum. Simply put, it needs to be slow when frozen and cooling, and it needs to be heated rapidly when recovered from low temperature. The reason for slow freezing is that if the cells are placed directly in an ultra -low temperature environment such as liquid nitrogen, the cells form a large ice crystal, which will damage the cells.
If you freeze it slowly, the cells can be dehydrated slowly to achieve the purpose of protecting cells. In addition, when recovering, it is also to prevent small ice crystals from forming large ice crystals, that is, the heavy crystals of ice crystals. Therefore, when everyone usually does cell frozen, it always causes cells to suffer losses, which is likely to have an impact in the step of freezing.
Several methods of cell frozen
Manual method: Cell frozen is usually stored in liquid nitrogen. The manual operation method is to cool the gradient in the refrigerator. Save the cells in the frozen storage tube, and put them in a refrigerator environment of 4 ° C, -20 ° C, -80 ° C in order. Frozen for 24 hours at -80 ° C before transferring to liquid nitrogen. Manual cooling does not require additional supplements of other consumables. It can be manually operated. It is the simplest, but it is not simple. The actual operation is troublesome. And the effect is not very good, because this cooling method is still not uniform, and it is not necessarily applicable for more fragile cells.
Gradient cooling box : The gradient cooling box sold on the market is specially used in the uniform cooling of the freezing process. The cooling speed is usually -1 ℃/minute. Put the frozen storage tube into the gradient cooling box, and place the gradient cooling box directly in the refrigerator environment of -80 ° C to spend the night without manual gradient operation. Then lower the depository tube and put it in liquid nitrogen. The effect of using gradient cooling boxes is better, because commercial cooling boxes on the market can ensure a roughly uniform cooling rate.
There are two common gradient cooling boxes on the market. A need to add isopropyl, usually a PC box body. When use, adding isopenol to the scaling line in the box when using it. The isopropanol is used as a carrier for heat storage and distribution.
Another kind does not need to be added with isopropyl, foaming, and the freezer can be placed directly during use, which is more convenient to operate.
The cooling box of isopropanol is recommended to replace the liquid after using it several times, but because isopropanol is a harmful liquid, which causes harm to the experiments and the environment, it can usually be used several times. However, it is necessary to ensure that the liquid is in a certain amount.
Non -programmed frozen storage: Use non -program frozen liquids that can be purchased on the market. Compared with the traditional frozen liquid, the internal component can reduce the damage to the cells of the ice crystal, so that there is no need to use the gradient to cool down, nor does it require the gradient cooling box. Frozen storage can be placed directly in a refrigerator environment of -80 ° C.
Many cell samples are very precious. In addition to us, we must use it when doing experiments. You also need to choose good products as much as possible in related product selection. Select the frozen storage tube with qualified quality, try to use the gradient cooling tool for freezing, and maximize the guarantee of low damage to cells to avoid small loss due to minor.