SV: [3dem] PCS vs cryoEM

[Kimberley Cheng]

Thank you all for responding so quickly to my e-mail! 

The cryoEM images show that the liposomes have different shapes, everything from spherical to elongated. A colleague of mine suggested that the difference in size determined by the two methods could be due to this issue. She said the PCS method works best on samples that are spherical, and results from samples containing different shapes could be misleading. 

Any thoughts about this?

Thanks!
/Kimberley



________________________________________
Från: fabian.kebbel at unibas.ch [fabian.kebbel at unibas.ch]
Skickat: den 31 oktober 2011 11:50
Till: Kimberley Cheng
Ämne: Re: [3dem] PCS vs cryoEM

Hi,

did you take the viscosity of the sample into account? This is part of
the Stokes-Einstein equation. When you enter a viscosity, which is too
low, you would yield too big hydrodynamic diameters.

All the best,

Fabian

Zitat von Kimberley Cheng <Kimberley.Cheng at ki.se>:

> Dear all,
>
> I recently got the following question "The particle size of our
> liposome product determined by cryoEM is about 75 nm, but the
> particle size determined by photon correlation spectroscopy (PCS) is
> about 110 nm. So we were wondering why the size determined by cryoEM
> is smaller than by PCS method?".
>
> Does anyone have a good explanation to this?
>
> Many thanks in advance!
> /Kimberley
>
>



Fabian Kebbel, PhD student
Center for Cellular Imaging and Nano Analytics (C-CINA)
Biozentrum, University of Basel
Mattenstrasse 26
CH-4058 Basel
Switzerland

fabian.kebbel at unibas.ch
http://www.c-cina.unibas.ch

phone: +41 61 38 73214


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