[jeffmoonchop]

Hi all, might be a hard question. I work with lipid nanoparticles and one of the best ways to look at the morphology of the particles is to do CryoTEM which is very expensive as I don't have my own to run routine analysis.

However, I did look at a couple of my samples and found that some of the particles have blebs or bubbles, probably due to excess phospholipid. I want to get rid of the blebs and I know that exchanging the phospholipid to a different one will help based off literature, and I want to vary the ratio of phospholipid to try and reduce the number of blebs.

I want to do these experiments but I don't have the money to send all the samples off for Cryo TEM. Does anyone know of any other methods I could use to detect blebs without looking at them?

I use a Zetasizer to measure Zavg and polydispersity so I was thinking polydispersity would be a good measure, as the blebs would increase poly, but we do also get a variety of particle sizes on the non bleb particles.

thanks for any input.

[Corribus]

What are they filled with? If you can deliberately fill them with something, there would be a whole lot of methods you could use.

[jeffmoonchop]

I'm assuming they are filled with water. The centre is a solid amorphous lipid core. I was thinking of maybe a fluorescent dye that is water soluble. The problem is most dyes intercalate with RNA (which is inside the centre). So a fluorescent dye that doesnt bind with RNA but remains in water. Might be hard to find.

Did you have any ideas?

[Corribus]

Some ideas:

Water soluble QDs (big, would depend on how big your nanoparticles and these "blebs" are)
Lanthanide ions
Ru(bpy)32+ (water soluble derivative)

Alternatively, you could label with a metal ion and do time-resolved (single particle) ICP-MS