simple question- please help me - (Apr/15/2010 )

Hello,
I am a beginner so please help me to understand following:

I centifuge my cells and dissolve the pellet in 5 ml media.

In 5ml cell suspension I have 250 mil cells/ml
In this 5 ml cell suspension I counted the cells and I have 1,8 mil cells/ml

I want 1 mil/ml and want to make 10 ml cell suspension

So I have 250 mil cells in 1ml
10 ml *10^6 cells= 10 mil cells ( in 10 ml I have 10 mil cells)

10 mil cells/ 250 mil cells = 0,04 ml= 40 ul. So I take 40 ul from my 5 ml cell suspesnion, but I need 10 ml in total volume so to the 40 ul cells ( I took from my 5ml cell suspension) I will add 9,96 ml media.

Is this calcultation right or this one below:

In 5ml cell suspension I have: 5ml *250 mil cells/ml= 1250 mil cells

1250 mil/10 mil = 8 ul I will take from the 5 ml cell suspension and I will add around 9,92 ml media

Thank you!

See this post in general biology subforum

bio08 on Apr 15 2010, 03:48 PM said:

The way you are phrasing your question is very confusing. So, to start, do you have TWO cell samples that you need to dilute to 1 mil/mL?? I bolded the confusing part of your post. You say that you have a cell pellet that you
resuspend in 5mL media and it is 250 mil/mL but then your next line says that you counted the cells and have 1.8 mil/mL. It's not clear what your samples really are and what you are trying to do but I'm going to try to help. You want a final cell suspension of 1 million cell/mL, right? And, you need 10mL of this 1 mil/mL, so you need 10 million cells. If your cell suspension is 250 mil/ml you need to figure out what volume will equal 10 million. Divide 250 million by 1000 tells you how many cells you have per uL. This is 250,000 cells/uL. Divide 10 million by 250,000 and you get 40. You need 40uL of the 250mil/mL cell suspension to get 10 million cells. Add this to 9960uL media and you have a 1 mil/mL suspension. Now, if you counted your cell suspension and saw that you actually only have 1.8 mil/mL this means you only have a total of 9 million cells in the 5 mL and you are not going to be able to make 10mL of a 1 mil/mL sample. Sorry, not enough cells. I hope this helped and didn't confuse you more!