Ultrasound-assisted Cu(I)-catalyzed azide-alkyne click cycloaddition as polymer-analogous transformation in chitosan chemistry. High antibacterial and transfection activity of novel triazol betaine chitosan derivatives and their nanoparticles

In this work, we involved ultrasound-assisted click CuAAC in chitosan chemistry. Ultrasound-mediated CuAAC between propargylic ester of betaine and azido chitosan derivative proceeds fast in water under aerobic conditions and gives rise novel water-soluble triazole betaine chitosan derivatives. Using ionic gelation technique, we prepared and characterized nanoparticles from the synthesized chitosan derivatives. We studied antibacterial and transfection activity of the novel chitosan derivatives and their nanoparticles. The nanoparticles with size ca. 100 nm and ζ-potential ca. +65 mV proved to possess outstanding antibacterial activity, which is much more than that of the triazole betaine derivatives in their native form, and it is equal to the activity of ampicillin and gentamicin. Opposite, triazole betaine chitosan derivatives in their native form are characterized by remarkable transfection activity as compared with their nanoparticles. The most active triazole betaine chitosan derivatives are derivatives of moderate molecular weight with moderate degree of substitution. Their transfection activity is extremely high for chitosan species and it is comparable (values of the same order) with activity of Lipofectin – commercially available gene delivery vector. © 2019 Elsevier B.V

Novel zinc(II)/chitosan-based composite: ultrasound-assisted synthesis, catalytic and antibacterial activity

Ultrasonic treatment of the reaction between chitosan and aromatic aldehyde, 4-formyl-3-hydroxy-5-hydroxymethyl-1,2-dimethylpyridin-1-ium iodide, resulted in its significant acceleration and increase in degree of derivatization. The CH=N bond of the prepared Schiff base was reduced, and the formed polymeric material was converted into the corresponding zinc(II) composite by treatment with ZnCl2 and NaOH. The obtained composite is non-toxic, possesses high antibacterial activity and can be employed as the catalyst in the Mannich reaction between benzaldehyde, phenylacetylene and piperidine. © 202

Natural polysaccharide-based smart (temperature sensing) and active (antibacterial, antioxidant and photoprotective) nanoparticles with potential application in biocompatible food coatings

Smart and active nanoparticles are of increasing interest in food films and coatings application. In the current study, we purpose novel nanoparticles NPs-4(1:5) and NPs-4(1:5.5), which possess simultaneously both smart (temperature sensitive) and active (antibacterial, light absorbing and antioxidant) properties. The obtained nanoparticles are based on PEG/MC core with anthocyanidin and sodium acetate, and chitosan/gallotannin-based shell. The nanoparticles have hydrodynamic diameter ca. 450 nm and are positively charged (ζ-potential is 21 mV for NPs-4(1:5) and +23 mV for NPs-4(1:5.5). NPs-4(1:5) and NPs-4(1:5.5) are thermochromic and turn from colorless to purple at ca. 20 °C 0 °C respectively. The nanoparticles possess antibacterial activity much more than the starting chitosan (MIC, μg/mL, E. coli: 1.35 (NPs-4(1:5)), 1.18 (NPs-4(1:5.5)) and 10.12 (chitosan); S. aureus: 1.14 (NPs-4(1:5)), 1.10 (NPs-4(1:5.5)) and 6.20 (chitosan)). The nanoparticles efficiently absorb ultraviolet light, have high antioxidant effect (0.051 trolox equivalents), are non-toxic and fully composed of substances approved for use in the food industry. © 2019 Elsevier B.V

Synthesis and Antibacterial Activity of Chitin Tetrazole Derivatives

New tetrazole derivatives of natural chitin polymers of high, medium, and low molecular masses with high, medium, and low degrees of substitution were synthesized and tested in vitro for antibacterial activity. The obtained tetrazole derivatives were characterized by pronounced antibacterial activity in vitro against S. aureus and E. coli. The chitin derivative of medium molecular mass with a medium degree of substitution had the highest antibacterial activity among all obtained derivatives. The antibacterial activity of this derivative as measured by bacterial growth inhibition zones was comparable to those of the antibiotics ampicillin and gentamycin. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Active antibacterial food coatings based on blends of succinyl chitosan and triazole betaine chitosan derivatives

In this work, we demonstrate that highly antibacterially active triazole betaine chitosan (TBC) component can be incorporated into succinyl chitosan sodium salt (SC-Na) matrix by simple mixing to afford quite compact and uniform films. Blending of SC-Na and TBC improves tensile strength and simultaneously diminishes oxygen and water vapor permeability of the formed blend films. These improvements are most pronounced for blend films with SC-Na:TBC ratio 1:1. Test applications of the blend films as food coatings for bananas reduced their weight loss, vitamin C loss, and respiration rate, and this resulted in a significantly extended shelf life of the coated bananas. Moreover, the prepared blend films are non-toxic since they are composed of non-toxic SC-Na and TBC. Finally, we demonstrate that the incorporation of TBC into the SC-Na matrix dramatically enhances the antibacterial activity of the blend coatings with a high TBC fraction (50 % and higher) and these results are among the best reported in the field of antibacterial films so far. © 2020 Elsevier Lt

Синтез и антибактериальная активность тетразольных производных хитина

The present study is devoted to the synthesis and study of the antibacterial activity in vitro of new tetrazole derivatives of natural polymer chitin of high, medium and low molecular weights with high, medium and low degree of substitution. The results showed that the obtained tetrazole derivatives are characterized by pronounced antibacterial activity in vitro against both S. aureus and E. coli strains. Among all derivatives, the highest antibacterial activity is demonstrated by a tetrazole derivative of chitin of moderate molecular weight and moderate degree of substitution. The antibacterial activity of this derivative as measured by the zone of inhibition of bacterial growth is comparable to the antibacterial activity of reference antibiotics ampicillin and gentamicin.Настоящее исследование посвящено синтезу и изучению антибактериальной активности in vitro новых тетразольных производных природного полимера хитина высоких, средних и низких молекулярных масс с высокими, средними и низкими степенями замещения. Полученные тетразольные производные характеризуются выраженной антибактериальной активностью in vitro в отношении S. aureus и E. coli. Среди всех полученных производных наибольшей антибактериальной активностью характеризуется производное хитина средней молекулярной массы умеренной степени замещения. Установленная по зоне ингибирования роста бактерий антибактериальная активность данного производного сопоставима с антибактериальной активностью антибиотиков ампициллина и гентамицина

Novel non-toxic high efficient antibacterial azido chitosan derivatives with potential application in food coatings

In this work, we developed a simple method for the preparation of N-(3-azido-2-hydroxypropyl)chitosan. We compared the antibacterial activity of N-(3-azido-2-hydroxypropyl)chitosans and previously synthesized N-(2-azidoethyl)chitosans. N-(3-azido-2-hydroxypropyl)chitosans possess higher antibacterial effect which is comparable with that of ampicillin and gentamicin. The effect is due to azido pharmacophore –CH2–CH(OH)–CH2–N3 (for N-(3-azido-2-hydroxypropyl)chitosan) or –CH2–CH2–N3 (for N-(2-azidoethyl)chitosan) introduced in chitosan chain, since the corresponding organic azides NH2–CH2–CH2–N3 and NH2–CH2–CH2–N3 are characterized by high antibacterial activity. However, high antibacterial organic azides NH2–CH2–CH2–N3 and NH2–CH2–CH2–N3 are characterized by high toxicity. Their conjugation to the chitosan chain saves their antibacterial effect, but strongly diminishes their toxicity, and the toxicity of the resulting derivatives is comparable with that of the starting chitosan. These findings are of interest to food science, since novel effective food coatings can be developed on basis of prepared derivatives. © 201