Summary Using Laboratory Consumables Problems

As we all know, it is essential to use laboratory consumables when doing related experiments, but we often encounter many problems, large and small. The following is a summary of several common questions and answers:

Summary using laboratory consumables problems:

cell culture dishes 100 mmSterile Pasteur Pipettes

1. Ask: What should I do if the cells are always clustered at the edge when seeded into a cell culture dish?
Reply:

  • How are your cells mixed? Is it pipetting or shaking the plate?
  • If it is the latter, if it shakes from side to side, it is very likely that the cells will be thrown to the surrounding parts due to the centrifugal force, resulting in fewer cells in the middle and more cells in the surrounding area!

Suggestion:

  • Before cultivating a seeded dish, place the dish in the incubator to soak for a few hours, then remove it.
  • Use light force when seeding cells. Add slowly to make the cell suspension flow into the wells of the plate, and the cultured cells grow basically evenly.
  • Remember to never shake the shaker or your cells will clump together as you said.

2. Ask: What I’m doing is a plaque formation experiment. Cells are best evenly distributed, but most wells are fine when inoculated with the virus, some are uneven. There are large differences between cell populations. If there is any way to add it?

Reply:

  • After cell digestion, pipetting into a single-cell suspension is critical! Make sure to have the same number of cells in each well when dividing!
  • Of course, the parallelism between holes is also an important processing factor. For example, when adding medicine, the medicine should be diluted and mixed to ensure that the concentration of each well is consistent!
  • In addition, when adding cells and drugs, the test group and control group should be added in order to avoid differences in cell density and drug concentration due to the order of adding samples!

3. Ask: Is there a good strategy for using Pasteur pipettes?

Reply:

  • If you use a Pasteur pipette, do not pipette too much at one time, because the cells in the pipette will automatically sink, and there are often more cells in the first few wells, and the cell suspension is more evenly distributed. route.
  • If using pipettes, handle and remove tips so as not to damage cells and so that each pipette corresponds to one well.
  • It is more accurate to add a one-to-one corresponding hole with a pointed tip. But also pay attention to the pause.
  • Do not shake after plating as shaking will cause cells to aggregate toward the center.

Some tips for cell culture:

1. Precipitation occurs in the culture solution, but the pH value remains unchanged
 Reason: Residual phosphate after washing with detergent precipitates media components
Countermeasures：

  • Should use more deionized water to rinse glassware, then sterilize
  • Warm the medium to 37°C and shake to dissolve it. If the precipitate still exists, discard the medium

2. Precipitation occurs in the culture medium and the pH changes at the same time
Reason: Bacterial or fungal contamination

Countermeasures: Discard cultures or sterilize with antibiotics

3. Cultured cells are not adherent

Reason: Trypsin over digestion and mycoplasma contamination

Countermeasures

  • Shorten trypsinization time or decrease trypsin concentration
  • Cultures were isolated and tested for mycoplasma. Clean the stand and incubator. If mycoplasma contamination is found, discard the culture
  • Change the composition of the cultural medium

 

There are more introduces about how to clean cell culture flasks, how to clean Petri dishes, etc.