title: Film-forming process and biocide assessment of high-molecular-weight chitosan as determined by combined ATR-FTIR spectroscopy and antimicrobial assays.
abstract: This pioneering study reported about the film-forming properties of high-molecular-weight chitosan as followed in situ by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and has implications in fields such as biomedical, pharmaceutical, packaging, and coating applications. From the results, it was observed that immediately after dissolution in an acetic acid aqueous solution and subsequent casting over the ATR crystal, the formed carboxylate antimicrobial (-NH3+ -OOCH) species are not stable in the film formulation and become reduced over time; further assays confirmed previous research, which suggested that the presence and stability of these groups is strongly dependent, among other factors, on storage conditions. As-received chitosan and chitosan neutralized in NaOH films did not exhibit biocide performance towards Staphylococcus aureus. The antimicrobial tests were also found to strongly relate the presence of a sufficient quantity of these carboxylate groups to the chitosan activity as a biocide agent. Moreover, a novel methodology based on the use of a normalized infrared band centered at 1405 cm(-1) is proposed which can be correlated with the antimicrobial character of the biopolymer.
authors.affiliation: Institute of Agrochemistry and Food Technology (IATA), CSIC, Apartado Correos 73,46100 Burjassot, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Fernandez-Saiz
authors.forename: M J
authors.initials: MJ
authors.lastname: Ocio
authors.forename: J M
authors.initials: JM
authors.lastname: Lagaron
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000900:Anti-Bacterial Agents; D048271:Chitosan