New water-soluble derivatives of chitin and their based nanoparticles: Antibacterial and catalytic activity

A facile route towards new chitin derivatives with both catalytical and biological activities is proposed in the course of methodology development aimed at the design of polyfunctional materials on the basis of renewable and accessible natural polysaccharides. Ultrasound-promoted and Cu(I)-catalyzed azido-alkyne click cycloaddition of the propargylic ester of nicotinic acid and its N-methylated analogue to the azido chitin derivative allowed us to obtain previously unknown non-toxic water-soluble derivatives of chitin. The obtained polymers and their based nanoparticles demonstrated a high antibacterial activity in vitro, which is comparable or even superior to that of commercial antibiotics ampicillin and gentamicin. New derivatives of chitin were also shown to be highly efficient and reusable (at least for 10 times) green catalysts for the aldol reaction in water. The catalysts can be easily separated from the reaction mixture by their precipitation with ethanol. The results obtained highlight prospects of further studies on chitin's application in the rational design of novel functional materials with valuable properties. © 2020 Elsevier B.V

New water-soluble chitin derivative with high antibacterial properties for potential application in active food coatings

The synthesis of new chitin derivatives through ultrasound-assisted treatment of the chitin with 1-azido-3-chloropropan-2-ol under Green Chemistry conditions is described. This is the first example of ultrasound-assisted polymer analogues transformation of chitin unaccompanied by noticeable backbone degradation or deacetylation. The obtained water-soluble azido chitin derivatives are characterized by high antibacterial activity, which is comparable with that of commercial antibiotics ampicillin and gentamicin. At the same time, they were demonstrated almost identical in vitro toxicity as unmodified chitin and chitosan. The antibacterial activity of the obtained polymers is mainly provided by azido moiety in their macromolecules. The conjugation of azido moiety to chitin backbone strongly diminishes the toxicity of the azido pharmacophore, but preserves its antibacterial properties. The most potent chitin derivative was used for the film coating of Ricotta cheese samples. This food coating proved to be efficient for the prolongation of shelf life of Ricotta cheese. © 2020 Elsevier Lt

Ultrasound-assisted catalyst-free phenol-yne reaction for the synthesis of new water-soluble chitosan derivatives and their nanoparticles with enhanced antibacterial properties

This work describes ultrasound-assisted phenol-yne addition of p-hydroxybenzaldehyde and propargylic ester of betaine hydrochloride giving only 2-((3-(4-formylphenoxy)allyl)oxy)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride as a product at 100 kHz 300 W in water. The ultrasonic assisted phenol-yne addition was enhanced to chitosan chemistry. Phenolic chitosan derivatives were obtained by treatment of chitosan with o-, m- or p-hydroxybenzaldehyde followed by reduction of the formed C[dbnd]N bound by NaBH4. The phenolic chitosan derivatives (phenolic component) were involved in ultrasound-mediated reaction with propargylic ester of betaine hydrochloride (yne component). The reaction led to betaine chitosan derivatives in different degree of substitution as o-, m- and p-isomers. The phenolic and betaine derivatives were tested as antibacterial agents against E. coli in comparison with reference antibiotic Tetracycline. Betaine derivatives showed high antibacterial activity. The most effective polymer was p-isomer of high substituted betaine derivative and its activity was more than 2 times higher than the activity of Tetracycline. The nanoparticles based on this polymer were obtained by ionic gelation method. They had 2Rh 126 nm, ξ-potential 20 mV and were more effective than the corresponding chitosan derivative. © 2019 Elsevier B.V

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

Efficient reinforcement of chitosan-based coatings for Ricotta cheese with non-toxic, active, and smart nanoparticles

We developed new smart and active nanoparticles with a thermal sensing core and antibacterial, antioxidant, and UV-absorbing shell. Incorporation of the newly designed nanoparticles into the chitosan matrix in a CS:NPs mass ratio 1:0.5 results in advanced nanocomposite food coatings, which possess enhanced mechanical and barrier properties, together with higher antibacterial, antioxidant, and UV-absorbing activity. Moreover, the resultant food coatings are non-toxic. Thus, we prepared new food coatings, in which active (antibacterial, antioxidant, UV-absorbing) and smart (temperature sensitive) properties are enabled by the same single type of nanoparticles. The developed food coatings are efficient for the prolongation and improvement of shelf life of Ricotta cheese. © 2020 Elsevier B.V

Synthesis of novel 1H-tetrazole derivatives of chitosan via metal-catalyzed 1,3-dipolar cycloaddition. Catalytic and antibacterial properties of [3-(1H-tetrazole-5-yl)ethyl]chitosan and its nanoparticles

New tetrazole derivatives of chitosan with low, moderate, and high degrees of substitution were obtained using a novel approach, i.e. metal-catalyzed 1,3-dipolar cycloaddition of azide ion to cyanoethyl chitosan in water – the most straightforward, selective and preparatively convenient route to tetrazole chitosan derivatives. Ionic gelation of these tetrazole derivatives with sodium tripolyphosphate resulted in nanoparticles with an apparent hydrodynamic diameter of 100–800 nm and ζ-potential of 22–57 mV. The tetrazole derivatives of chitosan and their nanoparticles were tested as catalysts of the aldol reaction between p-chlorobenzaldehyde and acetone. The tetrazole derivatives have been found to possess better catalytic properties than the corresponding nanoparticles. The obtained data indicate that the tetrazole-chitosan polymers exhibit high catalytic activity in aldol reaction, and these catalysts are among the best studied so far. Tetrazole derivatives and their nanoparticles were also tested as antibacterial agents. The in vitro antibacterial activity against S. aureus and E. coli of the tetrazole-chitosan-based nanoparticles is much more than the activity of the corresponding tetrazole-chitosan polymers, and their activity is comparable with that of antibiotics ampicillin and gentamicin. © 201

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

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

Water-soluble triazole chitin derivative and its based nanoparticles: Synthesis, characterization, catalytic and antibacterial properties

In this work, we treated chitin with 2-(azidomethyl)oxirane and successfully involved the resultant azido chitin derivatives in the ultrasound-assisted Cu(I)-catalyzed azido-alkyne click (CuAAC) reaction with propargylic ester of N,N,N-trimethyl glycine. Thus, we obtained novel water-soluble triazole chitin derivatives. The triazole chitin derivatives and their nanoparticles are characterized by a high in vitro antibacterial activity, which is the same or even higher than that of commercial antibiotics ampicillin and gentamicin. The obtained derivatives are non-toxic. Moreover, the obtained water-soluble polymers are highly efficient green catalysts for the aldol reaction in green solvent water. The catalysts can be easily extracted from the reaction mixture by its precipitation with green solvent ethanol followed by centrifugation and they can be reused at least 10 times. © 2021 Elsevier Lt

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