Antimicrobial and cytocompatible chitosan, N,N,N-trimethyl chitosan, and tanfloc-based polyelectrolyte multilayers on gellan gum films.

In this work free-standing gels formed from gellan gum (GG) by solvent evaporation are coated with polysaccharide-based polyelectrolyte multilayers, using the layer-by-layer approach. We show that PEMs composed of iota -carrageenan (CAR) and three different natural polycationic polymers have composition-dependent antimicrobial properties, and support mammalian cell growth. Cationic polymers (chitosan (CHT), N , N , N -trimethyl chitosan (TMC), and an amino-functionalized tannin derivative (TN)) are individually assembled with the anionic iota -carrageenan (CAR) at pH 5.0. PEMs (15-layers) are alternately deposited on the GG film. The GG film and coated GG films with PEMs are characterized by infrared spectroscopy with attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle (WCA) measurements. The TN/CAR coating provides a hydrophobic (WCA = 127°) and rough surface (R q = 243 ± 48 nm), and the TMC/CAR coating provides a hydrophilic surface (WCA = 78°) with the lowest roughness (R q = 97 ± 12 nm). Polymer coatings promote stability and durability of the GG film, and introduce antimicrobial properties against Gram-negative (Salmonella enteritidis) and Gram-positive (Staphylococcus aureus) bacteria. The films are also cytocompatible. Therefore, they have properties that can be further developed as wound dressings and food packaging. • A commercial gellan gum is characterized, supporting stable films due to the metallic ions presence in its composition. • The solvent evaporation method provides a stiffer gellan gum film. • The film is coated with polyelectrolyte multilayers due to the carboxylate moieties on the gellan gum. • Chitosan/ iota -carrageenan and N , N , N -trimethyl chitosan/ iota -carrageenan coatings support antimicrobial activities. • The coated films can be applied in the food and biomedical fields. [ABSTRACT FROM AUTHOR]