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

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

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

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

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

Chitosan derivatives and their based nanoparticles: ultrasonic approach to the synthesis, antimicrobial and transfection properties

In the present work, we demonstrate that alkylation of chitosan by alkyl halides, aza-Michael reaction with chitosan, and AdN-E reaction of chitosan with aldehydes can be efficiently mediated by ultrasound. An optimization of ultrasonic irradiation parameters allowed us to (i) accelerate the rate of the reactions dramatically, (ii) achieve high selectivity, and (iii) preserve integrity of the polysaccharide backbone avoiding its depolymerization. We evaluated antibacterial/antifungal and transfection activity of 8 different derivatives of chitosan and their based nanoparticles in vitro. Moreover, we studied antibacterial activity of the most efficient polymer and their based nanoparticles in vivo. The tested polymer proved to be superior to reference commercial antibiotics ampicillin and gentamicin. © 2020 Elsevier Lt

Novel heterocyclic chitosan derivatives and their derived nanoparticles: Catalytic and antibacterial properties

The metal-assisted nitrone-nitrile cycloaddition reaction is apply to empower chitosan chemistry. The ultrasonic irradiation has proven to efficiently accelerate the cycloaddition affording new heterocyclic (1,2,4-oxadiazoline) chitosan derivatives and avoiding ultrasonic degradation of the chitosan macromolecules. By varying the nitrone nature, both water- and toluene-soluble chitosan derivatives were successfully synthesized. Relying on the ionic gelation approach nanoparticles of heterocyclic chitosan derivatives were prepared. Water-soluble chitosan derivative demonstrated a high antibacterial activity coupled with low toxicity. The toxicity of the synthesized heterocyclic chitosan derivatives and their based nanoparticles are comparable with those of the starting chitosan, while their antibacterial activity is superior. Toluene-soluble derivatives are shown to be efficient homogeneous catalysts towards monoglyceride synthesis via the epoxide ring opening. They efficiently catalyze selective conversion of fatty acids and glycidol into corresponding monoglycerides allowing one to simplify significantly the procedure for separating the reaction product from the catalyst for its recovery and reusage. © 2020 Elsevier B.V