Charged Polypeptide Vesicles with Controllable Diameter

Contribution from the Materials Department, University of California at Santa Barbara, Santa Barbara, California 93106, USA.
Journal of the American Chemical Society (Impact Factor: 12.11). 10/2005; 127(35):12423-8. DOI: 10.1021/ja053557t
Source: PubMed


We report the preparation and characterization of charged, amphiphilic block copolypeptides that form stable vesicles and micelles in aqueous solution. Specifically, we prepared and studied the aqueous self-assembly of a series of poly(L-lysine)-b-poly(L-leucine) block copolypeptides, KxLy, where x ranged from 20 to 80 and y ranged from 10 to 30 residues, as well as the poly(L-glutamatic acid)-b-poly(L-leucine) block copolypeptide, E60L20. Furthermore, the vesicular assemblies show dynamic properties, indicating a high degree of membrane fluidity. This characteristic provides stimuli-responsive properties to the vesicles and allows fine adjustment of vesicle size using liposome-based extrusion techniques. Vesicle extrusion also provides a straightforward means to trap solutes, making the vesicles promising biomimetic encapsulants.

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    • "The formation of purely polypeptide polymer vesicles was first demonstrated with the amphiphilic diblock co-polypeptide [poly(N ε -2-(2-(2-methoxyethoxy)ethoxy)acetyl-L- lysine] x -(poly-L-leucine) y (K x L y ) (Bellomo 2004) where the size and structure of these vesicles are dictated primarily by the ordered conformation of the peptide segments. Further work with K x L y has demonstrated the tunability of the aggregates where the fluidity of the vesicle membrane allows for control of vesicle size and the morphology of aggregates can be tuned with changes in the chain lengths of polylysine and polyleucine (Holowka 2005). By replacing the poly-lysine block of the K x L y co-polypeptide with poly-arginine (R x L y ), it is possible to impart the enhanced cellular delivery properties of other arginine-rich protein-transduction domains (i.e. "
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