Lookup NU author(s): Dr Stephen Swioklo,
Professor Che Connon
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Macroscopic capsules, with tunable properties based on hierarchical self-assembly on multiple lengthscales, are prepared from the co-operative self-assembly of polysaccharide and peptide amphiphiles. Different formulations can be used to create flexible membrane sacs in solution, soft capsules or rigid free-standing capsules. Samples are prepared by injecting a solution containing sodium alginate, with or without graphene oxide (GO), into a matrix consisting of a solution containing the peptide amphiphile PA C-16-KKFF (K: lysine, F: phenylalanine), with or without CaCl2. Graphene oxide is added to the hybrid materials to modulate the mechanical properties of the capsules. Injection of sodium alginate solution into a pure PA matrix provides a flexible membrane sac in solution, while injection of NaAlg/GO solution into a PA matrix gives a soft capsule. Alternatively, a rigid free-standing capsule is made by injecting a NaAlg/GO solution into a PA + CaCl2 matrix solution. A comprehensive insight into the hierarchical order within the capsules is provided through analysis of X-ray scattering data. A novel "Langmuir-Blodgett" mechanism is proposed to account for the formation of the sacs and capsules as the alginate solution is injected at the interface of the PA solution. The capsules show a unique antibacterial effect specific for the Gram positive bacterium Listeria monocytogenes, which is an important human pathogen. The hybrid nanostructured capsules thus have remarkable bioactivity and due to their tunable structural and functional properties are likely to have a diversity of other future applications.
Author(s): Castelletto V, Kaur A, Hamley IW, Barnes RH, Karatzas KA, Hermida-Merino D, Swioklo S, Connon CJ, Stasiak J, Reza M, Ruokolainen J
Publication type: Article
Publication status: Published
Journal: RSC Advances
Online publication date: 26/01/2017
Acceptance date: 13/01/2017
ISSN (print): 2046-2069
Publisher: Royal Society of Chemistry
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