title: Physical properties and antibacterial activity of chitosan/acemannan mixed systems.
abstract: The aim of the present study was to investigate the mechanical and thermal properties of mixed chitosan-acemannan (CS-AC) mixed gels and the antibacterial activity of dilute mixed solutions of both polysaccharides. Physical hydrogels of chitosan comprising varying amounts of non-gelling acemannan were prepared by controlled neutralization of chitosan using ammonia. As the overall acemannan concentration in the mixed hydrogel increased while fixing that of CS, the mechanical strength decreased. These results indicate that AC perturbs the formation of elastic junctions and overall connectivity as it occurs in the isolated CS network. Heterotypic associations between CS and AC leading to the formation of more compact microdomains may be at play in reducing the density of the gel network consolidated by CS, possibly due to shorter gel junctions. Micro-DSC studies at pH 12.0 seem consistent with the suggestion that molecular heterotypic associations between CS and AC may be at play in determining the overall physical properties of the mixed gel systems. In dilute solution, CS showed antimicrobial activity against Staphylococcus aureus but not against Escherichia coli; AC did not exert antimicrobial activity against any of the two bacterial species. In blended solutions of both polysaccharides, as the amount of AC increased, the antimicrobial activity of the system against S. aureus ceased. In conclusion, this study demonstrates that it is feasible to incorporate acemannan in chitosan-acemannan gels and that although the mechanical strength decreases due to the presence of AC, the gel network persists even at high amount of AC. This study anticipates that the CS-AC mixed gels may offer promise for the future development of biomaterials such as scaffolds to be used in wound therapy.
authors.affiliation: Laboratorio de Biopolímeros, CIAD, Km 0.6 carretera a la Victoria, Hermosillo, Sonora 83000, Mexico; Departamento de Ingenieria Quimica-Bioquimica, Instituto Tecnológico de Mazatlan, Calle Corsario 1 No. 203, Col. Urias, Mazatlan, Sinaloa 82070, Mexico; CIAD Guaymas, Carretera al Varadero Nacional Km 6.6, Guaymas, Sonora 85480, Mexico.
authors.forename: Amada Yerén
authors.initials: AY
authors.lastname: Escobedo-Lozano
authors.affiliation: Laboratoire des Matériaux Polymères et des Biomatériaux-UMR CNRS, 5627 Lyon, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Domard
authors.affiliation: Departamento de Biología y Bioquímica, Universidad de Sonora, Blv. Luis Encinas y Rosales S/N, Col. Centro, Hermosillo, Sonora, Mexico.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Velázquez
authors.affiliation: Laboratorio de Biopolímeros, CIAD, Km 0.6 carretera a la Victoria, Hermosillo, Sonora 83000, Mexico. Electronic address: goycoole@uni-muenster.de.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Goycoolea
authors.affiliation: CIAD Guaymas, Carretera al Varadero Nacional Km 6.6, Guaymas, Sonora 85480, Mexico. Electronic address: waldo@ciad.mx.
authors.forename: Waldo M
authors.initials: WM
authors.lastname: Argüelles-Monal
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D048271:Chitosan / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D008351:Mannans / Q000737:chemistry / Q000494:pharmacology; D012212:Rheology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D008351:Mannans; D048271:Chitosan; C058414:acemannan
keywords: Acemannan; Aloe vera; Antibacterial activity; Chitosan; Mixed gels