Question

-Why is it important to use a seperate serological pipette for media and cell solutions?
-What is the purpose of using Trypsin EDTA and what does EDTA and trypsin do specifically?
  

Answer 1

1. Serological pipettes generally come in disposable packing because in cell culture experiments it is very important to maintain sterile conditions and see that there is no chance for contamination.

          In cell culture experiments we should use the separate pipette for media and cell solutions because the media is first prepared which contains some solidifying agents like agar and plated first and allowed to solidify before adding the cell solution. If we use the same pipette for transfer of cell solution it may not assure the even flow or the pipette may be blocked because of the traces of the media components that were solidified in it.

2.      Calcium-EDTA is usually used in cell culture experiments to detach the cells from the plates or flasks and to remove cell-cell interactions.

EDTA acts as a chelating agent on adhesion molecules like cadherins make them loose their interaction by sequestering calcium ions.

Trypsin is a proteolytic enzyme that hydrolyses the peptides acts on these cadherins and hydrolyzes them and thus detaches cell-cell interaction in the cell solution.