Antimicrobial activity of organic–inorganic hybrid films based on gelatin and organomodified silicones

Abstract

Gelatin–siloxane hybrid films containing antimicrobial agents were prepared in the two‐step procedure. First, gelatin was chemically modified with organomodified silicones containing epoxy (S1) and both epoxy and fluoroalkyl groups (S2). Next, antimicrobial agents such as lysozyme, EDTA, and nisin, in various concentrations, were introduced into obtained hybrid solution, prior to solvent casting of the films. Antimicrobial activity of prepared samples, as well as neat gelatin and gelatin–siloxane hybrid as a reference, was investigated using a modified agar diffusion method against several bacterial strains (Aeromonas hydrophila, Bacillus subtilis, Escherichia coli) and opportunistic fungus (yeast species Candida albicans). Prepared gelatin–siloxane films were characterized using FT‐IR, thermal and SEM analysis. Mechanical properties and swelling behavior of the samples were also investigated. The influence of type and amount of organosilicon compound used for modification of gelatin, as well as type and concentration of applied active agent on antimicrobial activity, was determined. We observed higher antimicrobial activity for all synthesized gelatin–siloxane hybrids than for unmodified gelatin with lysozyme, nisin, and EDTA prepared as comparison. Moreover, samples obtained with siloxane containing fluoroalkyl groups (S2) showed higher resistance to microbial agents than hybrids with S1 siloxane. Hybrid films showed also better water stability than neat biopolymer.

Phytocompounds of Bistorta macrophylla (D. Don) Sojak. as bioavailability enhancers of fluconazole and amphotericin B to better manage Candida species infections

“…Decanoic acid (capric acid) is a class of medium chain fatty (MCFA) that are known to create pores in the membranes and impair the cell permeability (Choi et al 2013) and leakage of the cytoplasmic content, and eventual cell death (Tsuchido et al). 1, 3-Dioxolane derivatives have been reported for antibacterial and antifungal activity against S. aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and against a yeast Candida albicans ATCC 10231 (Küçük et al 2011).Similarly, antimicrobial activity of organic-inorganic hybrid lms based on gelatin and organomodi ed silicones (Heptamethyltrisiloxane) have been reported byWojciechowska et al (2018). Either alone or in combination, these phytocompounds present in the rhizome extract of B. macrophylla could be responsible for antifungal activity, antioxidant activity, and enhancing the potency of uconazole and amphotericin B.…”

Desenvolvimento de filmes com atividades antioxidante e antimicrobiana empregando extrato hidroetanólico de folha de pitangueira e nisina ou natamicina

“…* G: * G: Filme controle de gelatina, sem adição de nisina; GN28: Filme de gelatina com adição de 28 mg de nisina/g de gelatina; GN56: Filme de gelatina com adição de 56 mg de nisina/g de gelatina; GN84: Filme de gelatina com adição de 84 mg de nisina/g de gelatina; GN112: Filme de gelatina com adição de 112 mg de nisina/g de gelatina.TG: Temperatura de transição vítrea; TM: Temperatura de fusão dos cristais; ∆HM: Entalpia de fusão dos cristais.As curvas de fluxo de calor da segunda varredura, por sua vez, foram típicos de materiais completamente amorfos, observando-se apenas as transições vítreas: TG1 ~ -ºC), Resultados similares foram reportados porSoares (2009), para filmes a base de blendas de galactomanana e amido, incorporados de nisina. A presença do antimicrobiano reduziu ligeiramente os valores de TG e TM, indicando que houve interação da nisina com os polímeros da blenda Wojciechowska et al (2018). também observaram uma redução nos valores de TG dos filmes de gelatina com a adição de nisina, sugerindo mudanças estruturais na proteína, induzidas pela formação de novas ligações covalentes.…”