I wanted to know the range (in micro seconds) of decay time for proteins up to at least 200 kDa (or proteins in general) in Dynamic Light Scattering (DLS) experiments.
I had gone through many articles where they mentioned the decay time is very faster for small molecules whereas decay time is slower for larger molecules or aggregates. However in many articles from the Correlogram graphs for smaller and lager molecules, I figured out for smaller molecules, the decay time is far less than 10 micro seconds.
If anyone can tell me the approximate range of decay time for proteins (up to 200 kDa) in DLS would be a great help.
Thanks in advance!!
The decay time depends on the solvent are using as well as the radius of the polymer (or protein in your case).
You could use eq. 8 in the attached paper to model different particle sizes and viscosities to get a better idea of your system.
Article Conformation and Interactions of Polystyrene and Fullerenes ...
Hello, I attached an example of protein nanoparticles. I don't know molecular weight but they are polymers of denatured ovalbumin molecules (43 kDa).
@ Rajeev Dattani: Thanks for your paper.
@ Osvaldo Sponton: thanks for your reply and the decay time is well under 10 micro seconds. The Size distribution chart depicting the intensity shows a broader peak.. Did you check the % polydispersity??
The decay time Tau depends on the diffusion coefficient D and wave vector q, Tau = 1 / ( D * q2 ) { where D = k*T / ( 6 * pi * eta * RH ) and q=2 pi n sin(theta/2) / lambda }.
Just for guidance, a BSA monomer [66kDa] has a hydrodynamic radius of about 3.6nm, a diffusion coefficient of about 60 micron2 / sec and in a Zetasizer Nano S at scattering angle 173 degrees and laser wave length 633nm a decay time of about 20 micro seconds [intensity autocorrelation function and distribution of relative intensity weighted relaxation times in attached figure]
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