Hi all!
I need some help, as I've been trying to troubleshoot and struggling with this for more than a few months.
I have DOPC + 05% Texas-Red-DHPE liposomes that I need to fuse into planar lipid bilayers, but the fusion doesn't happen once they are applied on my glass slides.
My liposomes are produced using the sonication, freeze-thawing and extrusion procedure. I have confirmed their size using Dynamic Light Scattering and they are < 100nm.
My supported bilayer formation were checked using FRAP and QCM-D, both indicating that there is liposome adhesion but NO fusion.
Additional relevant info:
- Lipids are rehydrated in PBS with and without Ca2+.
- Argon is used to avoid oxidation.
- Glass slides are cleaned with Piranha solution.
Thank you all for your help, it's greatly appreciated!
Dear Suwannee Ganguillet ,
I first recommend you to read the following paper: Jass, J., Tjärnhage, T., & Puu, G. (2000). From liposomes to supported, planar bilayer structures on hydrophilic and hydrophobic surfaces: an atomic force microscopy study. Biophysical journal, 79(6), 3153-3163.
https://www.sciencedirect.com/science/article/pii/S0006349500765490
I noticed that you try to use DOPC. This is a typical bilayer forming lipid according to the structure-shape concept, see for example:
Cullis, P. T., & Kruijff, B. D. (1979). Lipid polymorphism and the functional roles of lipids in biological membranes. Biochimica et Biophysica Acta (BBA)-Reviews on Biomembranes, 559(4), 399-420. (free in Google Scholar, see figure 7)
Seddon, J. M. (1990). Structure of the inverted hexagonal (HII) phase, and non-lamellar phase transitions of lipids. Biochimica et Biophysica Acta (BBA)-Reviews on Biomembranes, 1031(1), 1-69. (see enclosed file)
My estimate would be that DOPC might be too stable, and you need a certain portion of so-called non-bilayer forming lipid.
Furthermore, in principle PC is considered as a neutral lipid, perhaps you need a certain portion of anionic (negatively charged) lipid.
My suggestion would be to first try a, in the literature, well-described mixture (in terms of composition and method) to make that work in your hands as well and then start to vary.
Hope this helps you somewhat.
Best regards.
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