I've been trying to disperse HA nano particles in 10% FBS, and to quantify the size of the nano particles in solution. I've tried using DLS but couldn't get any reliable data on hydrodynamic size or distribution. I believe this is due to the polydispersity of my solution caused by a multitude of various proteins being present.
I've read about using Nano particle tracking and analysis as an alternative, which has much better resolution than DLS, but has worse repeatability compared to DLS since it looks at less particles. So I was wondering what other alternatives are there for assessing particle size and distribution of nano particles in biological media?
Of the publications that i've read that report on same parameters, the majority have used the DLS technique, but with the issues that arise when using this technique on nano particles dispersed in serum how reliably can I trust the data that has been published?
Any thoughts or ideas would be greatly appreciated.
Thanks
Dear Dominic, I mede my PhD at the Department for Physical Chemistry at Uppsala University, where The Svedberg got his Nobel prize for experimentally veryfying Einstein's theory for colloidal diffusion. You could repeat his experiments, performed almost 100 years ago, using an ultra-microscope and an ultra-centrifuge (his invention). 2) You could also use Fourier Transform Pulsed Gradient Self-Diffusion NMR, which I did, in my PhD work. With this method, you can obtain the individual Self-Diffusion Coefficients in multicomponent systems. There are surely other methods, but, at present, I must go do some work in the lab, so I'll be back later. / Johan Carlfors at www.ontargetchemistry.com, Uppsala, Sweden.
Hi Dominic,
I would recommend you have a look at the research of Prof. Günter Allmaier at TU Vienna in Austria; see: www.cta.tuwien.ac.at/iac/biopa/staff/guenter_allmaier/ . His research group has used many techniques, amongst others Gas-phase Electrophoretic Mobility Molecular Analysis (GEMMA), which is now commercialized as MacroIMS Macroion Mobility Spectrometer.
Cheers,
/Oliver
Hi Dominic,
I would like to recommend you a purification or separation step prior to DLS analysis.
The multiple sized components in a solution often cause high PDI, reporting "poor" quality criteria. Please take a filtration, chromatography, or centrifuge to remove the other proteins out of NP solution, as possible as you can. Then, you may get a lower PDI value, which shall be successful for the DLS.
Hi Dominic,
SAXS is also a good alternative. From these experiments you can get the mean value and polydispersity too.
SALUT!
Tony
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