RESUMO
We used nanoparticles which possess simultaneously active (antimicrobial, UV-protective and antioxidant) and smart (temperature sensing) properties. The nanoparticles (2Rh = 450 nm, PDI = 0.118 ± 0.014, ζ-potential = 21 mV and Tg = 8 ± 1 °C) are based on polyethylene glycol (PEG)/methyl cellulose (MC) core with anthocyanidin and sodium acetate, and chitosan/gallotannin-based shell. The core of nanoparticles acts as a temperature indicator, changing its color from colorless into deep purple at 8 °C, while the shell provides antimicrobial (due to chitosan), UV-protective and antioxidant (due to gallotannin) effects. We incorporated these nanoparticles into the chitosan matrix. The coatings demonstrated improved mechanical and barrier properties compared with the pure chitosan coating. The elaborated coatings pronouncedly improve the shelf-life of Ricotta cheese. Moreover, they serve as thermo indicators, which warn about cheese storage at an unacceptable temperature. Thus, we developed new coatings in which all properties are enabled by a single type of nanoparticles.
Assuntos
Anti-Infecciosos/química , Quitosana/química , Embalagem de Alimentos/métodos , Nanopartículas/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Queijo/análise , Escherichia coli/efeitos dos fármacos , Fungos/efeitos dos fármacos , Taninos Hidrolisáveis/química , Metilcelulose/química , Nanopartículas/toxicidade , Polietilenoglicóis/química , Staphylococcus aureus/efeitos dos fármacos , Temperatura , Resistência à TraçãoRESUMO
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.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Quitosana/farmacologia , Nanopartículas/química , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Aspergillus fumigatus/efeitos dos fármacos , Configuração de Carboidratos , Células Cultivadas , Quitosana/síntese química , Quitosana/química , Escherichia coli/efeitos dos fármacos , Geotrichum/efeitos dos fármacos , Células HEK293 , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos , Ondas UltrassônicasRESUMO
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.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/antagonistas & inibidores , Quitosana/farmacologia , Nanopartículas/química , Catálise , Quitosana/efeitos da radiação , Reação de Cicloadição , Compostos Heterocíclicos/química , Concentração de Íons de Hidrogênio , Metais/química , Monoglicerídeos/química , Nanopartículas/efeitos da radiação , Nitrilas/química , Óxidos de Nitrogênio , Polissacarídeos/química , Ultrassom , Água/químicaRESUMO
In this work, we demonstrate that the thiol-yne click reaction could be efficiently mediated by ultrasonic irradiation and implement the ultrasound-assisted thiol-yne click reaction to chitosan chemistry as a polymer-analogous transformation. We optimize power and frequency of ultrasound to preserve selectivity of the click reaction and avoid ultrasonic degradation of the chitosan polymer chain. Thus, we obtain a new water-soluble betaine. Using ionic gelation of the obtained betaine derivatives of chitosan, we prepare nanoparticles with a unimodal size distribution. Furthermore, we present results of antibacterial and transfection activity tests for the chitosan derivatives and their based nanoparticles. The derivative with a medium molecular weight and a high degree of substitution demonstrated the best antibacterial effect. It derived nanoparticles with a size of ca. 100 nm and ζ-potential of ca. +69 mV revealed even higher antibacterial activity, slightly superior to commercial antibiotics ampicillin and gentamicin. On the contrary, the obtained polymers possess a much more pronounced transfection activity as compared with their based nanoparticles and species with a low degree of substitution acts as the most efficient transfecting agent. Moreover, the obtained betaine chitosan derivatives as well as their derived nanoparticles are non-toxic.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Cátions/química , Quitosana/química , Química Click , Nanopartículas/química , Sonicação , Compostos de Sulfidrila/química , Antibacterianos/síntese química , Catálise , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fenômenos Químicos , Técnicas de Química Sintética , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Análise EspectralRESUMO
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 100kHz 300W 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 CN 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 126nm, ξ-potential 20mV and were more effective than the corresponding chitosan derivative.
Assuntos
Alcinos/química , Quitosana/química , Quitosana/farmacologia , Nanopartículas/química , Fenóis/química , Ondas Ultrassônicas , Água/química , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Benzaldeídos/química , Betaína/química , Técnicas de Química Sintética , Quitosana/síntese química , Escherichia coli/efeitos dos fármacos , SolubilidadeRESUMO
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.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Azidas/química , Quitosana/química , Quitosana/farmacologia , Embalagem de Alimentos , Antibacterianos/toxicidade , Quitosana/toxicidadeRESUMO
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.
Assuntos
Betaína/química , Quitosana/química , Cobre/química , Nanopartículas/química , Triazóis/química , Ondas Ultrassônicas , Alcinos/química , Antibacterianos/química , Antibacterianos/farmacologia , Azidas/química , Catálise , Quitosana/farmacologia , Química Click , Reação de Cicloadição , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Células HEK293 , Humanos , Peso Molecular , TransfecçãoRESUMO
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.
Assuntos
Antibacterianos/química , Antioxidantes/química , Materiais Biocompatíveis/química , Embalagem de Alimentos , Nanopartículas/química , Polissacarídeos/química , Substâncias Protetoras/química , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Materiais Biocompatíveis/farmacologia , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Polietilenoglicóis/química , Substâncias Protetoras/farmacologia , Análise Espectral , TemperaturaRESUMO
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 100-800â¯nm and ζ-potential of 22-57â¯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.