Basic Introduction to Flow Cytometry

Hi guys, it’s the 5th week already, everyone still going great? Hope you are =)

Anyway, it’s not my turn to post this week, but I decided to still post something this week so to help everyone understand more about the principle of Flow Cytometry which I am fortunate enough to be working with one.

Why would I want to do this, is because I am worried if everyone understand what I was posting during my 1st week where I bombarded everyone with tons of information.

First, over the weeks, I am going to introduction on the following basic principles:
1) Hydrodynamic focusing of the sample
2) Light collection & how they are measured
3) Sorting principle of Fluorescent Activated Cell Sorter (FACS)
4) Data analysis for flow cytometry

For this posting, I will only be explaining about hydrodynamic focusing of the sample:

I am sure all of you know that Flow Cytometry is used to analysis the cells profile based on varying factors (I’ll touch more about the factors under point 2 for next posting – refer to above).

However, before the data could be obtained, the cells have to first be loaded into the Flow Cytometry for sample processing. How the sample is load into the Flow Cytometry is very important, as the sample stream has to be in single cell line in order to record single cell profiles.

Figure 1: Cross-sectioned laser beam focused by laser optics lens
Retrived, July 25, from:
http://biology.berkeley.edu/crl/flow_cytometry_basic.html

The above diagram shows how the sample is being focused into a single cell stream before passing through the laser beam, which is the interrogation point where data about the cells are collected. As you can see, the flowing sheath fluid cause the focusing of the sample stream into single cell line.

Hydrodynamic focusing:
A higher pressure from the flowing sheath fluid causes the lower pressure from the sample to form a single flowing cell line.

That is why the surrounding sheath fluid has to be higher in pressure than the sample fluid, else hydrodynamic focusing could not occur.

That’s all for this posting, will post the next topic the following week.

Please do tell me if you find this useful for you in understanding, as this is something extra I plan on blogging to help everyone understand Flow Cytometry. Because I worried that my first post was too much in the content and hard for everyone to understand.

So, is it okay if I continue the postings to explain the basic principles of Flow Cytometry?

Everyone! Have a nice day =)

Posted by:
Low Quan Jun (0607243C)
TG02
Group 08
25 July 2008