I have prepared DPPC:Chol liposomes 10mg/ml 1:1 weight ratio with microfluidics nanoassemblr bench top with FR 1:1 and TFR 12ml/min. Solvents used (Ethanol: Distilled water).The size on Malvern Zetasizer was around 150nm.
Then I repeated the same experiment using PBS buffer instead of water and the particle size was 190nm. I increased the FR to 2:1 then 5:1 however the particle size jumped up tp 600 nm. Any ideas what's the reason behind the large particle size. In most papers even the ones by nano-assmblr stated that high flow rate decrease the size and 5:1 should produce a very small size.
-Why high flow rate didn't produce small size below 100nm as mentioned in papers?
-Also does using water reduce the particle size ?
Tia Mo
Liposomes self-assemble in a solvent. The solvent, pH, the size of the amphiphilic molecules change, the size of liposomes change. Self-organization occurs due to hydrophobic (solvophobic) interaction. If the flow rate is in laminar mode, then the size of the liposomes may not change. If the flow is in a turbulent mode, then the size of the liposomes may change.
the stability of some liposomal formulations is external physiological environment- and internal microenvironmental pH-dependent. These suggest that creating an acidic microenvironment in the internal chamber of liposomes is beneficial to the stability of some liposomal , as well as for other pH-sensitive molecules.
I don't think using buffer or water has any effect on particle size. the influence of other factors can be discussed.
Hello Tia Mo , it could be that the DLS data in water are just not ideal, i.e. your liposomes are aggregated, or air bubbles. Maybe you can add the data file (.dts) to this discussion? The other suggestion I would have would be to contact Precision Nano Systems directly. They do have an appnote showing higher flow rate does not always lead to smaller particles
http://www.precisionnanosystems.com/docs/default-source/pni-files/app-notes/pni-app-bt-012.pdf
Yes, this occurs with me when using the water and PBS.The liposome participation with PBS
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