washing of attached bacterial cells - (Jun/08/2013 )

I have read many papers on bacterial attachment on metal/glass samples and there live and dead staining afterwards to see the number of live cells and dead bacterial cells attached on the samples.


In most of the papers the procedure followed is given below:

The sample (metal/glass) is exposed to some medium containing bacterial cells. After each experiment the samples were removed from the medium gently rinsed with sterile 0.85% (w/v) NaCl (or PBS) solution to remove the unattached bacterial cells, followed by two rinses with sterile deionized (DI) water.

QUESTION: Are dead bacterial cells are more easily removed than live bacterial cells?

Any help on this is highly appreciated. Thanks

You are familiar with live/dead staining - was that not useful?
Removed by what? Your initial rinsing step was intended to remove "unattached " cells so what was the objective of the other 2 rinses with DI? btw - suggest you be more specific about protocol than a subjective "gentle" rinsing.

Thanks for your comment Phil. Actually I want to ask that the initial rinsing step which people use to remove "unattached" cells, will that unattached cells include both dead and live cells?

Fiaq Khan on Mon Jun 10 12:30:15 2013 said:

It will contain both yes.
I dont know the details about what you are doing, but you will rinse away all the cells that are not yet attached "good enough" to stay attached.
BTW: the attached cells are also both living or dead cells. Dead cells dont just go "away" (if you wait long enough, yes they will be gone, but its a ongoing proces: cells will die the entire time.. so any time you take sample, you will have dead cells too.. or cells that are damaged and die while you progress them etc...

Its pretty easy to understand: if you have biofilm formation, it grows and grows.. well the cells in the deepest parts of the biofilm are surrounder by millions of other cells and extracellulair saccharides etc.. those cells arent going anywhere.. they are stuck... (they will break down, "be eaten" by the others, but this takes time...)
I hope you understand what I mean.