Which can reliably determine size/polydispersity of sonicated liposomes (~200 nm target) for an undergraduate biotechnology project? Preferably low-cost and equipment-limited.
Mohammed Shadab Shah
1. Conducting sedimentation analysis by the gravimetric method on a torsion balance on a simple device. 2. Determining the average particle size in colorless ash by the turbidity spectrum method
https://kpfu.ru/staff_files/F248041034/Metodichka_kolloidnaya_khimiya_Art_.pdf
Hi!
Besides DLS, optical microscopy with image analysis (using phase-contrast or fluorescence if labeled) can give rough size estimates but lacks precision for ~200 nm liposomes. Nanoparticle Tracking Analysis (NTA) is more accurate but costly. UV-Vis turbidity measurements can indirectly assess size trends. For low-cost settings, gel filtration (SEC) or filtration through defined pore membranes can help estimate size distribution qualitatively.
Message me or contact on [email protected] for size estimation through DLS. May be i can help you with the instrument.
Alan F Rawle , I am anxious to know how Disc centrifuge can be an alternate to DLS.As per my practical experience-" A centrifuge does not measure particle size by itself. It separates particles based on their size, shape, and density, but it does not give an exact size measurement unless coupled with other analytical methods"
Also,i would agree to Yuri Mirgorod on his analytical suggestions for the same.
It would be wonderful to know your suggestions on this, as it can also help in my current research.
Mani Sharma A simple Google search will help. You are correct in that a disc centrifuge separates on the basis of size, shape, and (relative) density. A disc centrifuge simply increases the acceleration due to gravity ('g') as used in gravity settling as mentioned by Yuri Mirgorod . A simple Stokes' Law calculation will tell you what material is likely to remain in suspension. Many sizing techniques will require other parameters for derivation but, if the material is similar chemically and only differing in size, then comparison is easily effected. For example, take a look at Joyce-Loebl and also the attached.
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