Antibacterial Films Made of Ionic Complexes of Poly(γ-glutamic acid) and Ethyl Lauroyl Arginate

Abstract

Abstract:The biocide agent LAE (ethyl α N-lauroyl L-arginate chloride) was coupled with poly(γ-glutamic acid) (PGGA) to form stable ionic complexes with LAE:PGGA ratios of 1 and 0.5. The nanostructure adopted by these complexes and its response to thermal changes were examined in detail by Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) using synchrotron radiation in real time. A layered biphasic structure with LAE filling the space between the polypeptidic sheets was adopted in these complexes. The complexes were stable up to above 250 • C, non-water soluble, and were able to form consistent transparent films. The release of LAE from the complexes upon incubation in aqueous buffer was examined and found to depend on both pH and complex composition. The antibacterial activity of films made of these complexes against Gram-positive (L. monocytogenes and S. aureus) and Gram-negative (E. coli and S. enterica) bacteria was preliminary evaluated and was found to be very high against the formers and only moderate against the later. The bactericide activity displayed by the LAE·PGGA complexes was directly related with the amount of LAE that was released from the film to the environment.

Ionic coupling of hyaluronic acid with ethyl N-lauroyl l-arginate (LAE): Structure, properties and biocide activity of complexes

“…Signals arising from the anomeric proton of the glucuronic unit of HyA and the methylene protons of the lauroyl moiety of LAE (signals 1 and j) were used to determine the composition of the complexes. The relative area quantification of these signals revealed that the complexes have compositions very close to those used for their synthesis (Table 1), with deviations within the range that could be expected according to results obtained for other ionic complexes of HyA previously studied by us (Tolentino, Alla, Martínez de Ilarduya & Muñoz-Guerra, 2013;Gamarra, Missagia, Morató, Muñoz-Guerra, 2017).…”

“…The FTIR spectra recorded from the LAE•HyA complexes are shown in Figure 1 data of the two components (Gilli et al, 1994;Gamarra, Missagia, Morató, Muñoz-Guerra, 2017). The spectra of the complexes include the bands characteristic of the two counterparts with relative intensities according to composition.…”

“…Thus LAE is known to interact positively with the anionic polysaccharides present in the food (Asker, Weiss, & McClements, 2009;Loeffler et al, 2014), and complexes of HyA with a diversity of organocationic compounds have been also described (Battistini et al, 2017;Bračič, Hansson, Pérez, Zemljič, & Kogej, 2015;Chytil, Trojan, & Kovalenko, 2016;Tolentino, Alla, Martínez de Ilarduya, & Muñoz-Guerra, 2013). Complexes of LAE with poly(-glutamic acid) (LAE•PGGA) with antibacterial properties have been recently described by us (Gamarra-Montes, Missagia, Morató, & Muñoz-Guerra, 2017).…”

Antibacterial Hydrogels Derived from Poly(γ-glutamic acid) Nanofibers

“…Different studies have been performed to prepare hydrogels based on γ-PGA from different crosslinking agents, but probably cystamine, a disulfide-crosslinking agent, is the more effective [ 19 , 20 ]. Published results indicated that the structure and content of the selected agent determined the pore size, the crosslinking degree, the water absorption and even the degradation profile [ 12 , 13 , 21 , 22 ].…”

Host–Guest Polymer Complexes

“…The next three articles reported the synthesis and electrostatic-force-induced complexation of anionic polyelectrolytes and dendrigraft poly(L-Lysine) [7], poly (γ-glutamic acid) and ethyl lauryl alginate [8], pillar [6]arene containing polyelectrolytes [9]. As shown by these studies, one of the advantages of utilizing polyelectrolytes is in the utilization of a layer-by-layer approach for the fabrication of thin films, which could be subsequently formulated for various applications, including: antibacterial films/patches.…”