I am using a lipid film technique where the lipids are dissolved in chloroform, dried into a lipid film and then rehydrated in tris buffer. The micelles are giving me three populations on the DLS, where I can see the small sized population (probably the micelles) but can also see presence of larger sized populations (indicating maybe I have formed large complexes, liposomes, or aggregates).
Does anyone have any tips to prevent this?
Dear Jane Doe ,
I presume you did more than ‘just’ hydrating the lipid film? There is/was some filtering or better sonication step involved. Where does your expectation of 20-30 nm come from? Perhaps the following is a good read:
Takayama R, Inoue Y, Murata I, Kanamoto I. Characterization of Nanoparticles Using DSPE-PEG2000 and Soluplus. Colloids and Interfaces. 2020; 4(3):28. https://doi.org/10.3390/colloids4030028
Like in this paper (Figure 2l), the three peaks are most likely small particles (1), the intended size (2) and aggregates (3).
Best regards.
Rob Keller thank you for your reply! I will be sure to check out that paper. And yes sonication without heat for 30 mins. Should I do longer? Some papers have overnight shaking. Also I have read that micelles are 10-70 nms with DSPE-PEG2k around this size and 5k a little larger
Dear Jane Doe ,
you have mentioned you have 3 different population on the size distribution of your liposomes.
Could you please specify it was distribution by intensity or volume/number? Since big nanoparticles scatters much more light, it changes interpretation of the results (check Mie theory).
First, filtration should help you to remove the possible impurities you could have in your Tris buffer. Filter it with 0.2 or 0.45µm cutoff sire to prevent to have some big impurities in your final solution (such as dust for example).
Then you can filtrate your liposomes after sonication. For sure, it's better to use glass vials during sonication to prevent the possibility to have microplastic in your suspension after sonication.
I hope you will find my advices useful.
Jane Doe
DSPE-PEG2k micelles are formed due to hydrophobic interaction, that is, water-mediated interaction. We observed the same peaks with the usual surfactant sodium dodecyl sulfate.
Preprint Supplementary information for Nuclear quantum effect in aque...
The formation of such micelles is accompanied by quantum fluctuations of water with a nuclear quantum effect.
Preprint Nuclear quantum effect in aqueous micellar surfactant solutions
Quantum fluctuations can be removed by adding an inorganic electrolyte if this does not interfere with your research.
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