RESUMEN
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.
Asunto(s)
Antibacterianos/química , Quitosano/síntesis química , Quitosano/farmacología , Óxido de Etileno/química , Nanopartículas/química , Triazoles/química , Aldehídos/química , Ampicilina/química , Exoesqueleto , Animales , Antiinfecciosos , Catálisis , Química Clic , Ésteres , Gentamicinas/química , Tecnología Química Verde , Iones , Espectroscopía de Resonancia Magnética , Solubilidad , Solventes , ViscosidadRESUMEN
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.
Asunto(s)
Antibacterianos/farmacología , Antifúngicos/farmacología , Quitosano/farmacología , Nanopartículas/química , Antibacterianos/síntesis química , Antibacterianos/química , Antifúngicos/síntesis química , Antifúngicos/química , Aspergillus fumigatus/efectos de los fármacos , Conformación de Carbohidratos , Células Cultivadas , Quitosano/síntesis química , Quitosano/química , Escherichia coli/efectos de los fármacos , Geotrichum/efectos de los fármacos , Células HEK293 , Humanos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos , Ondas UltrasónicasRESUMEN
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.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Quitosano/antagonistas & inhibidores , Quitosano/farmacología , Nanopartículas/química , Catálisis , Quitosano/efectos de la radiación , Reacción de Cicloadición , Compuestos Heterocíclicos/química , Concentración de Iones de Hidrógeno , Metales/química , Monoglicéridos/química , Nanopartículas/efectos de la radiación , Nitrilos/química , Óxidos de Nitrógeno , Polisacáridos/química , Ultrasonido , Agua/químicaRESUMEN
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. 450â¯nm and are positively charged (ζ-potential is 21â¯mV for NPs-4(1:5) and +23â¯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.
Asunto(s)
Antibacterianos/química , Antioxidantes/química , Materiales Biocompatibles/química , Embalaje de Alimentos , Nanopartículas/química , Polisacáridos/química , Sustancias Protectoras/química , Antibacterianos/farmacología , Antioxidantes/farmacología , Materiales Biocompatibles/farmacología , Pruebas de Sensibilidad Microbiana , Nanopartículas/ultraestructura , Polietilenglicoles/química , Sustancias Protectoras/farmacología , Análisis Espectral , TemperaturaRESUMEN
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. 100â¯nm and ζ-potential ca. +65â¯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.