Stimuli responsive fibrous hydrogels from hierarchical self-assembly of a triblock copolypeptide.
Soft Matter
; 11(2): 331-42, 2015 Jan 14.
Article
em En
| MEDLINE
| ID: mdl-25379651
ABSTRACT
In this work, the self-assembly behavior and pH responsiveness of a triblock copolypeptide in aqueous media are demonstrated. The copolypeptide was composed of a central pH responsive poly(l-glutamic acid) (PGA), flanked by two hydrophobic poly(l-alanine) blocks (PAla) (PAla5-PGA11-PAla5). This system showed a pH-responsive transition from short tapes to spherical aggregates by increasing the pH, as a result of deprotonation of the PGA block and a conformational change from α-helix to random coil. Increasing the ionic strength to physiological conditions (0.15 M) has triggered fibrillar self-assembly through intermolecular hydrogen bonding of PAla end-blocks that form ß-sheet nanostructures, in conjunction with charge screening of the central random coil PGA segments. At elevated concentrations a thermo-responsive free supporting hydrogel was obtained, consisting of rigid ß-sheet based twisted superfibers, resulting from hierarchical self-assembly of the copolypeptide. Yet, morphological transformation of this nanostructure was observed upon switching the pH from physiological conditions to pH 4. An unexpected morphology constituted of α-helix-based giant nanobelts was observed as a consequence of the secondary peptide transitions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
Idioma:
En
Revista:
Soft Matter
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Grécia