Exploiting Dimerization of Purely Peptidic Amphiphiles to Form Vesicles

Abstract

Short, amphiphilic peptides self‐assemble into vesicles due to dimerization. These additional interactions lead to the formation of stable peptide membranes. The vesicles demonstrate pH responsiveness and the ability to encapsulate hydrophobic and hydrophilic moieties within their structure, and therefore may be used as an advanced, biodegradable, drug‐delivery system.

Mimicking the cell membrane with block copolymer membranes

“…LS proved that the responsiveness of a pH and temperature dual responsive poly(butadiene)‐poly( L ‐lysine) (PB‐P(Lys)) block copolymer vesicle derives partially from changes in secondary structure within the polypeptide chain 57. It was found that, at high pH and temperature, P(Lys) corona chains undergo a change in secondary structural from α‐helix to β‐sheet, which causes an increase in vesicle size 58…”

“…In principle, vesicles possess the potential to encapsulate hydrophilic moieties within aqueous cores and to integrate hydrophobic compounds within the hydrophobic membrane layer. In an initial trial, this encapsulation method was successfully carried out through the incorporation of hydrophilic Alexa Fluor 488 and hydrophobic BODIPY 650/665 into amphiphilic peptide assemblies 58. The co‐localization of both fluorophores indicates the presence of vesicles.…”

Self-assembled Structures from Amphiphilic Peptides

“…The lamellar thickness of 8.3 ± 1.3 nm was attributed to a peptide double-layer. [11] Charge compensation between glutamic acid and lysine, combined with hydrophobic interaction, is the apparent driving force towards layer formation.…”

“…[1,5] The sequence of amphiphilic peptides is organized into two regions: the hydrophobic and the hydrophilic part. The latter is predominantly occupied by charged and polar amino acids; these are: arginine (R), [6,7] histidine (H), [7,8] lysine (K), [9][10][11][12][13][14][15] aspartic acid (D), [16,17] glutamic acid (E), [11,18] serine (S), threonine (T), asparagine (N), glutamine (Q), and cysteine (C). [13] The design of the hydrophobic part is based on amino acids with neutral and nonpolar side-chains such as glycine (G), [16] alanine (A), [15,19] valine (V), [17,20] leucine (L), [9,17] isoleucine (I), [21] methionine (M), phenylalanine (F), [22,23] tyrosine (Y), and tryptophan (W).…”

“…[13] The design of the hydrophobic part is based on amino acids with neutral and nonpolar side-chains such as glycine (G), [16] alanine (A), [15,19] valine (V), [17,20] leucine (L), [9,17] isoleucine (I), [21] methionine (M), phenylalanine (F), [22,23] tyrosine (Y), and tryptophan (W). [7,[10][11][12][13][14]23] Depending on the hydrophobic to hydrophilic ratio and the sequence, various self-assembled structures can be constructed -as indicated in the associated references for the above amino acids -although the hydrophobicity is moderated by the polar character of the peptide's backbone.…”