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1.
Succinylation of polyallylamine: influence on biological efficacy and the formation of electrospun fibers
Lucija Jurko, Matej Bračič, Silvo Hribernik, Damjan Makuc, Janez Plavec, Filip Jerenec, Sonja Žabkar, Nenad Gubeljak, Alja Štern, Rupert Kargl, 2021, original scientific article

Abstract: Succinylation of proteins is a commonly encountered reaction in biology and introduces negatively charged carboxylates on previously basic primary amine groups of amino acid residues. In analogy, this work investigates the succinylation of primary amines of the synthetic polyelectrolyte polyallylamine (PAA). It investigates the influence of the degree of succinylation on the cytotoxicity and antibacterial activity of the resulting polymers. Succinylation was performed in water with varying amounts of succinic anhydride and at different pH values. The PAA derivatives were analyzed in detail with respect to molecular structure using nuclear magnetic resonance and infrared absorbance spectroscopy. Polyelectrolyte and potentiometric charge titrations were used to elucidate charge ratios between primary amines and carboxylates in the polymers. The obtained materials were then evaluated with respect to their minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa. The biocompatibility was assessed using mouse L929 fibroblasts. The degree of succinylation decreased cytotoxicity but more significantly reduced antibacterial efficacy, demonstrating the sensitivity of the fibroblast cells against this type of ampholytic polyelectrolytes. The obtained polymers were finally electrospun into microfiber webs in combination with neutral water-soluble polyvinyl alcohol. The resulting non-woven could have the potential to be used as wound dressing materials or coatings.
Keywords: polyallylamine hydrochloride, succinylation, aqueous chemistry, cytotoxicity, antimicrobial effect, electrospinning, nanofibers, mouse L929 fibroblasts, Staphylococcus aureus, Pseudomonas aeruginosa
Published in DiRROS: 19.07.2024; Views: 79; Downloads: 97
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2.
Cytotoxicity and antibacterial efficacy of betaine- and choline-substituted polymers
Lucija Jurko, Damjan Makuc, Alja Štern, Janez Plavec, Bojana Žegura, Perica Bošković, Rupert Kargl, 2023, original scientific article

Abstract: Cationic charge has been widely used to increase polymer adsorption and flocculation of dispersions or to provide antimicrobial activity. In this work, cationization of hydroxyethyl cellulose (HEC) and polyvinyl alcohol (PVA) was achieved by covalently coupling betaine hydrochloride and choline chloride to the polymer backbones through carbonyl diimidazole (CDI) activation. Two approaches for activation were investigated. CDI in excess was used to activate the polymers’ hydroxyls followed by carbonate formation with choline chloride, or CDI was used to activate betaine hydrochloride, followed by ester formation with the polymers’ hydroxyls. The first approach led to a more significant cross-linking of PVA, but not of HEC, and the second approach successfully formed ester bonds. Cationic, nitrogen-bearing materials with varying degrees of substitution were obtained in moderate to high yields. These materials were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, polyelectrolyte titration, and kaolin flocculation. Their dose-dependent effect on the growth of Staphylococcus aureus and Pseudomonas aeruginosa, and L929 mouse fibroblasts, was investigated. Significant differences were found between the choline- and betaine-containing polymers, and especially, the choline carbonate esters of HEC strongly inhibited the growth of S. aureus in vitro but were also cytotoxic to fibroblasts. Fibroblast cytotoxicity was also observed for betaine esters of PVA but not for those of HEC. The materials could potentially be used as antimicrobial agents for instance by coating surfaces, but more investigations into the interaction between cells and polysaccharides are necessary to clarify why and how bacterial and human cells are inhibited or killed by these derivatives, especially those containing choline.
Keywords: hydroxyethyl cellulose, polyvinyl alcohol, antimicrobial, S. aureus, P. aeruginosa, L929 mouse fibroblast, cationic polymer
Published in DiRROS: 12.07.2024; Views: 134; Downloads: 114
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