Your browser doesn't support javascript.
loading
Rigid, Fibrillar Quaternary Structures Induced by Divalent Ions in a Carboxylated Linear Polysaccharide.
Diener, Michael; Adamcik, Jozef; Bergfreund, Jotam; Catalini, Sara; Fischer, Peter; Mezzenga, Raffaele.
Afiliación
  • Diener M; Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland.
  • Adamcik J; Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland.
  • Bergfreund J; Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland.
  • Catalini S; Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland.
  • Fischer P; European Laboratory for Non-Linear Spectroscopy (LENS), Università di Firenze, 50121 Florence, Italy.
  • Mezzenga R; Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland.
ACS Macro Lett ; 9(1): 115-121, 2020 Jan 21.
Article en En | MEDLINE | ID: mdl-35638668
ABSTRACT
Polysaccharides are ubiquitous in nature; they serve fundamental roles in vivo and are used for a multitude of food, pharmaceutical, cosmetic biomaterials, and biomedical applications. Here, the structure-property function for low acetylated Gellan gum hydrogels induced by divalent ions was established by means of optical, rheological, and microscopic techniques. The hydrogels interacted with visible light as revealed by birefringence and multiple scattering, as a consequence of quaternary, supramolecular fibrillar structures. The molecular assembly and structure were elucidated by statistical analysis and polymer physics concepts applied to high-resolution AFM height images and further supported by FTIR. This revealed intramolecular coil-to-single helix transitions, followed by lateral aggregation of single helices into rigid, fibrillar quaternary structures, ultimately responsible for gelation of the system. Calcium and magnesium chloride were shown to lead to fibrils up to heights of 6.0 nm and persistence lengths of several micrometers. The change in molecular structure affected the macroscopic gel stiffness, with the plateau shear modulus reaching ∼105 Pa. These results shed light on the two-step gelation mechanism of linear polysaccharides, their conformational molecular changes at the single polymer level and ultimately the macroscale properties of the ensued gels.

Texto completo: 1 Bases de datos: MEDLINE Idioma: En Revista: ACS Macro Lett Año: 2020 Tipo del documento: Article País de afiliación: Suiza

Texto completo: 1 Bases de datos: MEDLINE Idioma: En Revista: ACS Macro Lett Año: 2020 Tipo del documento: Article País de afiliación: Suiza