Assembly of Protein Structures onto Liposomes by Using Non-specific and Specific Interactions


Three distinct interactions were used for this assembly:

  • Electrostatic attraction.
  • Specific avidin-biotin or streptavidin-biotin binding.
  • Specific polysaccharide/lectin binding.


TEM micrograph

Bar = 100 nm.

Ferritin structures assembled by electrostatic interaction and cross-linking. TEM of negatively stained samples.
a) Vesicle with adherent non-fixed ferritin array. The liposomes are positively charged by incorporating some amount of HTAB.
b) Ferritin shell cross-linked by glutaraldehyde over a liposome;
c) Ferritin aggregate obtained after the liposomes are dissolved by solubilisation with non-ionic surfactant (Tween 20).



TEM micrograph

Bar = 100 nm.

Liposome/ferritin assemblies obtained by "lock-and-key" binding.
a) Schematics of the avidin-biotin or streptavidin-biotin assembly;
b) Electron micrographs of vesicles covered with ferritin by avidin-biotin binding. The vesicles incorporate of biotinylated lipid and approximately equimolar amount of HTAB.;
c) Schematics of the assembly based on Concanavalin A-mannan binding. The liposomes are first coated with cholesterol-anchored polysaccharide layer;
d) Vesicle whose ferritin shell is attached by Concanavalin A-mannan binding.


Concluding Remarks

Complex microstructured particles could be assembled from liposomes and ferritin by using colloid interaction schemes including either non-specific or a combination between non-specific and specific interactions. The acquired data can find application in the future fabrication of microstructured, multicomponent or functionalised protein and liposome/protein assemblies. The knowledge, control, and multi-step modification of the colloid interactions in the system appear to be the real tool for "smart" particle assembly.



O. D. Velev, Adv. Biophys., 34, 139 (1997).



    © Copyright O. D. Velev 1998


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