title: Polysaccharide-based freestanding multilayered membranes exhibiting reversible switchable properties.
abstract: The design of self-standing multilayered structures based on biopolymers has been attracting increasing interest due to their potential in the biomedical field. However, their use has been limited due to their gel-like properties. Herein, we report the combination of covalent and ionic cross-linking, using natural and non-cytotoxic cross-linkers, such as genipin and calcium chloride (CaCl2). Combining both cross-linking types the mechanical properties of the multilayers increased and the water uptake ability decreased. The ionic cross-linking of multilayered chitosan (CHI)-alginate (ALG) films led to freestanding membranes with multiple interesting properties, such as: improved mechanical strength, calcium-induced adhesion and shape memory ability. The use of CaCl2 also offered the possibility of reversibly switching all of these properties by simple immersion in a chelate solution. We attribute the switch-ability of the mechanical properties, shape memory ability and the propensity for induced-adhesion to the ionic cross-linking of the multilayers. These findings suggested the potential of the developed polysaccharide freestanding membranes in a plethora of research fields, including in biomedical and biotechnological fields.
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal. jmano@dep.uminho.pt and ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Joana M
authors.initials: JM
authors.lastname: Silva
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal. jmano@dep.uminho.pt and ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Sofia G
authors.initials: SG
authors.lastname: Caridade
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal. jmano@dep.uminho.pt and ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal. jmano@dep.uminho.pt and ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: João F
authors.initials: JF
authors.lastname: Mano
mesh_terms: D000268:Adhesiveness; D000464:Alginates / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D008567:Membranes, Artificial; D013718:Tensile Strength
chemical_list: D000464:Alginates; D003432:Cross-Linking Reagents; D008567:Membranes, Artificial; D048271:Chitosan; D002118:Calcium