RESUMO
Self-assembled microparticles from chitosan (SAMC) was prepared by depolymerization induced by potassium persulfate. Particle size distribution data showed averaged around 5 µm size and SEM indicated the sequential formation of "RBC" shaped particles. Soluble SAMC consists of 'deacetylated' residues as revealed by 13C NMR. SAMC showed antitumor efficacy in human breast cancer cell lines through mitigation in cell proliferation, colony formation and cell migration. Anti-tumor and anti-angiogenic properties of SAMC was found in vivo Ehrlich ascites tumor (EAT) bearing mice model resulting in tumor growth inhibition (EAT control, 17.4 ml; SAMC treated, 6.8 ml) and improved survival potency (15 days). Moreover, the decrease in ascites VEGF secretion (EAT control, 1354 ng; SAMC treated, 351 ng) accompanied with reduction in neovessel formation. Apoptosis induction by SAMC was confirmed by DNA fragmentation, caspase activities and fluorescence staining methods respectively. SAMC may be a safe candidate for anti-tumor dietary supplement production in food industry.
Assuntos
Apoptose/efeitos dos fármacos , Carcinoma de Ehrlich/tratamento farmacológico , Quitosana/farmacologia , Neovascularização Patológica/tratamento farmacológico , Animais , Configuração de Carboidratos , Carcinoma de Ehrlich/metabolismo , Carcinoma de Ehrlich/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quitosana/síntese química , Quitosana/química , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Camundongos , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neovascularização Patológica/patologiaRESUMO
N-trimethyl chitosan (TMC) is a multifunctional polymer that can be used in various nanoparticle forms in the pharmaceutical, nutraceutical and biomedical fields. In this study, TMC was used as a mucoadhesive adjuvant to enhance the oral bioavailability and hence antitumour effects of gemcitabine formulated into nanocomplexes composed of poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) conjugated with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). A central composite design was applied to achieve the optimal formulation. Cellular uptake and drug transportation studies revealed the nanocomplexes permeate over the intestinal cells via adsorptive-mediated and caveolae-mediated endocytosis. Pharmacokinetic studies demonstrated the oral drug bioavailability of the nanocomplexes was increased 5.1-fold compared with drug solution. In pharmacodynamic studies, the formulation reduced tumour size 3.1-fold compared with the drug solution. The data demonstrates that TMC modified nanocomplexes can enhance gemcitabine oral bioavailability and promote the anticancer efficacy.
Assuntos
Antineoplásicos/uso terapêutico , Desoxicitidina/análogos & derivados , Portadores de Fármacos/química , Nanopartículas/química , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Quitosana/síntese química , Quitosana/química , Quitosana/metabolismo , Desoxicitidina/química , Desoxicitidina/farmacocinética , Desoxicitidina/uso terapêutico , Portadores de Fármacos/síntese química , Portadores de Fármacos/metabolismo , Liberação Controlada de Fármacos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Nanopartículas/metabolismo , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/síntese química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/metabolismo , Ratos Sprague-Dawley , Vitamina E/síntese química , Vitamina E/química , Vitamina E/metabolismo , GencitabinaRESUMO
Nanotechnology paves the way for introducing nanoscale fertilizers, pesticides, and elicitors. This study intends to address the synthesis of chitosan/zinc oxide nanocomposite (CS-ZnONP) and its biological assessment in in-vitro conditions. The zinc oxide nanoparticles (ZnONPs) were successfully coated with the chitosan (CS) polymer through a cost-effective approach. Transmission electron microscopy and Fourier transform infrared spectroscopy assessments proved the surface capping of chitosan polymer on ZnONP. The nanocomposite was more capable of improving growth and biomass than the bare ZnONPs. The application of the nanocomposite increased the concentration of chlorophylls (51%), carotenoids (70%), proline (2-fold), and proteins (about 2-fold). The supplementation of culture medium with the nanomaterials upregulated enzymatic antioxidant biomarkers (catalase and peroxidase). The activity of the phenylalanine ammonia-lyase enzyme also displayed a similar significant upward trend in response to the nano-supplements. The CS-ZnONP treatment considerably enhanced the accumulation of alkaloids (60.5%) and soluble phenols (40%), implying stimulation in secondary metabolism. The micropropagation test revealed that the CS-ZnONP treatment improved the organogenesis performance. Overall, the nanocomposite can be considered a highly potent biocompatible elicitor.
Assuntos
Capsicum/química , Quitosana/síntese química , Nanocompostos/química , Técnicas de Cultura de Tecidos , Óxido de Zinco/química , Quitosana/química , Cinética , Nanocompostos/ultraestrutura , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
To explore the disease resistance mechanism of chitosan conjugates, chitosan-gentamicin conjugate (CS-GT) was synthesized and systematically characterized, the immune mechanism of CS-GT on Litopenaeus vannamei infected with Vibrio parahaemolyticus was further explored. The results showed that imine groups in CS-GT were effectively reduced. Dietary supplementation of CS-GT can significantly increase the survival rate, total hemocyte counts, the antioxidant and immune related enzyme activity levels of shrimps (P < 0.05), which are all dose-dependent under the experimental conditions. In addition, CS-GT can protect the hepatopancreas from invading bacteria and alleviate inflammation. Particularly, CS-GT promotes the expressions of legumain (LGMN), lysosomal acid lipase (LIPA) and Niemann-Pick type C2 (NPC2) up-regulated. It is speculated that CS-GT may stimulate the lysosome to phagocytose pathogens more effectively. In conclusions, shrimps fed with CS-GT can produce immune response via lysosome and greatly improve the disease resistance to Vibrio parahaemolyticus.
Assuntos
Quitosana/análogos & derivados , Quitosana/uso terapêutico , Gentamicinas/uso terapêutico , Imunidade Inata/efeitos dos fármacos , Fatores Imunológicos/uso terapêutico , Penaeidae/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Quitosana/síntese química , Cisteína Endopeptidases/metabolismo , Suplementos Nutricionais , Gentamicinas/síntese química , Hemócitos/metabolismo , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/microbiologia , Hepatopâncreas/patologia , Fatores Imunológicos/síntese química , Penaeidae/imunologia , Penaeidae/metabolismo , Penaeidae/microbiologia , Fagócitos/metabolismo , Esterol Esterase/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Vibrio parahaemolyticus/patogenicidadeRESUMO
Self-healing hydrogels with pH-responsiveness could protect loaded drugs from being destroyed till it arrives to the target. The pectin-based hydrogel is a candidate due to the health benefit, anti-inflammation, antineoplastic activity, nontoxicity, and biospecific degradation, et al. However, the abundant existence of water-soluble branched heteropolysaccharide chains influenced its performance resulting in limitation of the potential. In the present study, we prepared a series of self-healing pectin/chitosan hydrogels via the Diels-Alder reaction. Moreover, pectin/chitosan composite hydrogel was prepared as a contrast. By comparison, it can be seen that the Diels-Alder reaction greatly improved the cross-linking density of hydrogels. The self-healing experiments showed excellent self-healing performance. In different swelling mediums, significant transformation in the swelling ratio was shown, indicating well-swelling property, pH- and thermo-responsiveness. The drug loading and release studies presented high loading efficiency and sustained release performance. The cytotoxicity assay that showed a high cell proliferation ratio manifested great cytocompatibility.
Assuntos
Quitosana/química , Portadores de Fármacos/química , Hidrogéis/química , Pectinas/química , Animais , Linhagem Celular , Quitosana/síntese química , Quitosana/toxicidade , Citrus/química , Reação de Cicloadição , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Fluoruracila/química , Furanos/síntese química , Furanos/química , Furanos/toxicidade , Hidrogéis/síntese química , Hidrogéis/toxicidade , Concentração de Íons de Hidrogênio , Cinética , Maleimidas/síntese química , Maleimidas/química , Maleimidas/toxicidade , Fenômenos Mecânicos , Camundongos , Pectinas/síntese química , Pectinas/toxicidade , TemperaturaRESUMO
pH-sensitive drug delivery systems based on amphiphilic copolymers constitute a promising strategy to overcome some challenges to cancer treatment. In the present study, quercetin-loaded chitosan/polyvinylpyrrolidone/γ-Alumina nanocomposite was fabricated through a double oil in water emulsification method for the first time. γ-Alumina was incorporated to improve the drug loading efficiency and release behavior of polyvinylpyrrolidone and chitosan copolymeric hydrogel. γ-Alumina nanoparticles were obtained by the sol-gel method with a nanoporous structure, high surface area, and hydroxyl-rich surface. Quercetin, a natural anticancer agent, was loaded into the nanocomposite as a drug model. XRD and FTIR analyses confirmed the crystalline properties and chemical bonding of the prepared nanocomposite. The size of drug-loaded nanocomposites was 141â¯nm with monodisperse particle distribution, having a spherical shape approved by DLS analysis and FE-SEM, respectively. Incorporating γ-Alumina nanoparticles improved the encapsulation efficiency up to 95%. Besides, swelling study and the quercetin release profile demonstrated that γ-Alumina ameliorated pH sensitivity of nanocomposite and a targeted controlled release was obtained. Various release kinetic models were applied to the experimental release data to study the mechanism of drug release. Through MTT assay and flow cytometry, the quercetin-loaded nanocomposite showed significant cytotoxicity on MCF-7 breast cancer cells. Also, the enhanced apoptotic cell death confirmed the anticancer activity of γ-Alumina. These results suggest that the chitosan/polyvinylpyrrolidone/γ-Alumina nanocomposite is a novel pH-sensitive drug delivery system for anticancer applications.
Assuntos
Óxido de Alumínio/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Quitosana/síntese química , Portadores de Fármacos , Nanoporos , Povidona/síntese química , Quercetina/farmacologia , Óxido de Alumínio/química , Antineoplásicos Fitogênicos/química , Neoplasias da Mama/patologia , Quitosana/análogos & derivados , Preparações de Ação Retardada , Composição de Medicamentos , Liberação Controlada de Fármacos , Feminino , Humanos , Concentração de Íons de Hidrogênio , Cinética , Células MCF-7 , Povidona/análogos & derivados , Quercetina/químicaRESUMO
In the current study, hemostatic compositions including a combination of chitosan and kaolin have been developed. Chitosan is a marine polysaccharide derived from chitins, a structural component in the shells of crustaceans. Both chitosan and kaolin have the ability to mediate a quick and efficient hemostatic effect following immediate application to injury sites, and thus they have been widely exploited in manufacturing of hemostatic composites. By combining more than one hemostatic agent (i.e., chitosan and kaolin) that act via more than one mechanism, and by utilizing different nanotechnology-based approaches to enhance the surface areas, the capability of the dressing to control bleeding was improved, in terms of amount of blood loss and time to hemostasis. The nanotechnology-based approaches utilized to enhance the effective surface area of the hemostatic agents included the use of Pluronic nanoparticles, and deposition of chitosan micro- and nano-fibers onto the carrier. The developed composites effectively controlled bleeding and significantly improved hemostasis and survival rates in two animal models, rats and rabbits, compared to conventional dressings and QuikClot® Combat Gauze. The composites were well-tolerated as demonstrated by their in vivo biocompatibility and absence of clinical and biochemical changes in the laboratory animals after application of the dressings.
Assuntos
Quitosana/administração & dosagem , Desenho de Fármacos , Hemostasia/efeitos dos fármacos , Hemostáticos/administração & dosagem , Caulim/administração & dosagem , Nanocompostos/administração & dosagem , Animais , Bandagens , Quitosana/síntese química , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Hemorragia/tratamento farmacológico , Hemorragia/fisiopatologia , Hemostasia/fisiologia , Hemostáticos/síntese química , Caulim/síntese química , Masculino , Nanocompostos/química , Coelhos , Ratos , Ratos Sprague-DawleyRESUMO
Synthetic selenium polysaccharides with potential bioactivity have drawn great interest due to the SeO bonds existing in the structure. Herein, N, O-selenized N-(2-carboxyethyl) chitosan (sNCCS) was synthesized through carboxyethylation and selenylation. Various characterizations were performed to identify the structure of sNCCS, indicating that SeO bonds were formed both at the C-6 hydroxyl groups and the introduced C-2 carboxyethyl groups. The highest yield and selenium content of all sNCCS reached 84.5% and 1.553 mg/g, respectively. In vitro evaluation exhibited that sNCCS has excellent bile acid binding capacity, which was 1.63, 2.00, and 2.55-fold higher than that of N-(2-carboxyethyl) chitosan (NCCS). Moreover, it was found that higher selenium content could significantly enhance the antioxidant properties of sNCCS. Importantly, no obvious cytotoxic effect had been observed on Caco-2 cells. Taken together, sNCCS with desirable biological activity and non-cytotoxicity might be considered as an effective ingredient in the fields of food or medicine.
Assuntos
Antioxidantes/síntese química , Quitosana/análogos & derivados , Selênio/química , Antioxidantes/química , Antioxidantes/farmacologia , Ácidos e Sais Biliares/química , Células CACO-2 , Quitosana/síntese química , Quitosana/química , Quitosana/farmacologia , HumanosRESUMO
The development of chitosan-gelatin (CS-G) hydrogels embedded with ampicillin-loaded hyaluronic acid nanoparticles (HA-NPs) for wound dressing is proposed. It was aimed to provide controlled ampicillin delivery by incorporation of HA-NPs into biocompatible CS-G hydrogel structure. According to in vitro ampicillin release studies, 55% of ampicillin was released from CS-G/HA-NPs hydrogels after 5 days. Antibacterial performance of CS-G/HA-NPs hydrogels was proven with agar disc diffusion test. For cytotoxicity assay, fibroblast cell viability increased in CS-G/HA-NPs hydrogels compared with CS-G group after 24 hr incubation. Consequently, the potential ability of CS-G/HA-NPs hydrogels as a controlled drug delivery system has been verified.
Assuntos
Antibacterianos/farmacologia , Quitosana/farmacocinética , Liberação Controlada de Fármacos/efeitos dos fármacos , Gelatina/farmacocinética , Ácido Hialurônico/farmacocinética , Nanopartículas/metabolismo , Ampicilina/síntese química , Ampicilina/farmacocinética , Animais , Antibacterianos/síntese química , Quitosana/síntese química , Avaliação Pré-Clínica de Medicamentos/métodos , Liberação Controlada de Fármacos/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Gelatina/síntese química , Humanos , Ácido Hialurônico/síntese química , Hidrogéis/síntese química , Hidrogéis/farmacocinética , Nanopartículas/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologiaRESUMO
Hydrogel can provide a favorable moisture environment for skin wound healing. In this study, a novel in-situ crosslinked injectable hydrogel was prepared using the water-soluble amidated pectin (AP) and oxidized chitosan (OC) through Schiff-base reaction without any chemical crosslinker. The influence of AP content on the properties of the hydrogel was systemically investigated. It showed that gelation time, pore structure, swelling capability and degradability of the hydrogel can be tuned by varying the content of amine and aldehyde groups from AP and OC. All the porous hydrogels with various AP contents (65%, 70%, and 80%) presented desirable gelation time, swelling property, high hemocompatibility and biocompatibility. Particularly, AP-OC-65 hydrogel presented superior swelling capability and better hemo- and bio-compatibility, owing to more residual amine sites in the hydrogel. Therefore, the injectable AP-OC-65 hydrogel has a greater potential for application to wound dressing or skin substitute.
Assuntos
Curativos Hidrocoloides , Quitosana/química , Pectinas/química , Pele/lesões , Cicatrização , Amidas/química , Animais , Bandagens , Materiais Biocompatíveis/química , Sobrevivência Celular , Células Cultivadas , Quitosana/síntese química , Reagentes de Ligações Cruzadas , Hemólise , Humanos , Hidrogéis/síntese química , Hidrogéis/química , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Pectinas/síntese química , Pectinas/ultraestrutura , Bases de Schiff , Espectroscopia de Infravermelho com Transformada de Fourier , TermodinâmicaRESUMO
Due to increasing reports of multidrug-resistant (MDR) Vibrio cholerae O1, the goal of this study was to characterize the in vitro antimicrobial activity of chitosan microparticles (CMs) to evaluate their potential as a novel therapeutic agent for cholera. We examined the antimicrobial activity of CMs against toxigenic V. cholerae O1 using direct enumeration, microscopy, and fluorescence microplate assays. Bacterial viability kinetics were measured with different concentrations of CMs, solution pH, and salt content using a live/dead staining technique. Growth inhibition of CM-exposed V. cholerae strains was conducted using a redox-sensitive stain and compared between wild-type and isogenic outer membrane (OM) mutants. CM concentrations above 0.1 wt % were sufficient to kill V. cholerae O1 suspensions with approximately 108 CFU/mL within 3 h. The nonviable cells demonstrated increased OM permeability that corresponded to gross morphological changes observed through scanning electron microscopy. CMs exhibited dose-dependent bactericidal activity that increased predictably at lower pH and decreased with salt addition. V. cholerae O1 strains lacking O-antigen were twice as susceptible to growth inhibition by CMs, whereas those with glycine modification to lipid A were ten times more resistant. We propose that CMs exert vibriocidal activity via electrostatic surface interactions between their positively charged amine groups and the negatively charged Gram-negative bacterial OM, resulting in disruption, increased permeability, decreased redox metabolism, and subsequent loss of cellular viability. Further research should be conducted in vivo to evaluate the efficacy of CMs as luminal agents to treat infections caused by MDR, toxigenic V. cholerae and other diarrheal pathogens.
Assuntos
Antibacterianos/farmacologia , Quitosana/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Vibrio cholerae O1/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Configuração de Carboidratos , Sobrevivência Celular/efeitos dos fármacos , Quitosana/síntese química , Quitosana/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Propriedades de Superfície , Vibrio cholerae O1/citologia , Vibrio cholerae O1/crescimento & desenvolvimentoRESUMO
Matricaria chamomilla L. has been used for centuries in many applications, including antiparasitic activity. Leishmaniasis is a parasitic disease, with limited treatments, due to high cost and toxicity. Thus, there is a need to develop new treatments, and in this context, natural products are targets of these researches. We report the development of chitosan nanocapsules containing essential oil of M. chamomilla (CEO) from oil-in-water emulsions using chitosan modified with tetradecyl chains as biocompatible shell material. The nanocapsules of CEO (NCEO) were analyzed by optical microscopy and dynamic light scattering, which revealed spherical shape and an average size of 800 nm. Successful encapsulation of CEO was further confirmed by fluorescence microscopy observations taking advantage of the autofluorescence properties of CEO. The encapsulation efficiency was around 90%. The entrapment of CEO reduced its cytotoxicity towards normal cells. On the other hand, the CEO was active against promastigotes and intracellular amastigotes, exhibiting IC50 of 3.33 µg/mL and 14.56 µg/mL, respectively, while NCEO showed IC50 for promastigotes of 7.18 µg/mL and for intracellular amastigotes of 14.29 µg/mL. These results demonstrate that encapsulation of CEO in nanocapsules using an alkylated chitosan biosurfactant as a "green" stabilizer is a promising therapeutic strategy to treat leishmaniasis.
Assuntos
Anti-Infecciosos/farmacologia , Quitosana/química , Leishmania/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Matricaria/química , Nanocápsulas/química , Óleos Voláteis/farmacologia , Anti-Infecciosos/química , Linhagem Celular , Quitosana/análogos & derivados , Quitosana/síntese química , Portadores de Fármacos/química , Difusão Dinâmica da Luz , Humanos , Iridoides/química , Queratinócitos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Microscopia de Fluorescência , Tamanho da Partícula , Tensão SuperficialRESUMO
(1) Background: Ionotropic gelation of cost-effective and eco-friendly biopolymer chitosan (Chit) is a novel and promising approach to the one-step synthesis of proton-conducting fuel cell bio-membranes.The method discovered by the author in 2011 and subsequently drowned among very few papers. This work aimed to relaunch this method through clear and effective communication of new unpublished results emphasizing the key aspects of this topic for successful dissemination of the results and significant future developments. (2) Methods and results: The mechanism of in-situ ionotropic gelation of Chit on an alumina substrate by phosphotungtate anions (PWA3-) was discussed and analyzed. The study sheds light on the effect of prolonged post-treatment in phosphotungstic acid (PWA) solution on the obtained chitosan/phosphotungstate (Chit-PWA) flat structures. Methods used included combined structural (XRD), thermal-gravimetric (DTG), electrochemical (in-situ EIS), compositional (EDX),morphological analysis (SEM), as well as the performances in a low temperature H2/O2 fuel cell(4) Conclusions: This contribution discloses novel possibilities aimed at increasing the impact of ionotropic gelation of chitosan on the scientific community working on the synthesis of novel proton conductive bio-composite membranes and structures.
Assuntos
Óxido de Alumínio/química , Quitosana/síntese química , Quitosana/química , Condutividade Elétrica , Técnicas Eletroquímicas , Géis/síntese química , Géis/química , Ácido Fosfotúngstico/química , PrótonsRESUMO
In-situ forming implants receive great attention for repairing serious bone injuries. The aim of the present study was to prepare novel chitosan in-situ forming implants (CIFI) loaded with bioactive glass nanoparticles and/or raloxifene hydrochloride (RLX). Incorporating raloxifene hydrochloride (RLX) as a selective estrogen receptor modulator was essential to make use of its anti-resorptive properties. The prepared formulae were tested for their in-vitro gelation time, drug release, injectability, rheological properties, erosion rate and morphological properties. Results revealed that the formulation composed of 1% (w/v) chitosan with 2% (w/v) NaHCO3 and 1% (w/v) bioactive glass nanoparticles (CIFI-BG) possessed the most sustained drug release profile which extended over four months with low burst release effect compared to the same formulation lacking bioactive glass nanoparticles (CIFI). Selected formulations were tested for their ability to enhance bone regeneration in induced puncture in rate tibia. Results declared that these formulations were able to enhance bone regeneration after 12 weeks in comparison to the untreated tibial punctures and that containing bioactive glass could be considered as novel approach for treatment of serious bone injuries which require long term treatment and internal mechanical bone support during healing.
Assuntos
Conservadores da Densidade Óssea/síntese química , Quitosana/síntese química , Composição de Medicamentos/métodos , Nanopartículas/química , Cloridrato de Raloxifeno/síntese química , Tíbia/efeitos dos fármacos , Animais , Conservadores da Densidade Óssea/administração & dosagem , Conservadores da Densidade Óssea/metabolismo , Regeneração Óssea/efeitos dos fármacos , Regeneração Óssea/fisiologia , Quitosana/administração & dosagem , Quitosana/metabolismo , Modelos Animais de Doenças , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Implantes de Medicamento/administração & dosagem , Implantes de Medicamento/síntese química , Implantes de Medicamento/metabolismo , Vidro/química , Masculino , Nanopartículas/administração & dosagem , Nanopartículas/metabolismo , Cloridrato de Raloxifeno/administração & dosagem , Cloridrato de Raloxifeno/metabolismo , Ratos , Ratos Sprague-Dawley , Tíbia/lesões , Tíbia/metabolismo , Resultado do TratamentoRESUMO
Organo-hydrogels are widely used in various fields, due to functional organic ingredients immobilized by the gel network or stored and protected by the gels. Herein, cellulose acetoacetate (CAA) served as reactive natural polymer emulsifier to stabilize thyme oil-in-water (O/W) emulsions. Hydroxypropyl chitosan (HPCS) was added to the continuous phase in emulsions to achieve the organo-hydrogel via the enamine bonds under mild conditions. The thyme@CAA emulsion with different loadings of the inner phase (up to 50%) displayed uniform droplets distribution (3-5 µm) and favorable stability. The organo-hydrogel was systematically analyzed by Fourier transform infrared spectroscopy, optical microscope, rheology analyses. The emulsion droplets evenly dispersed in the three-dimensional network. The modulus of organo-hydrogels depended on the viscosity of precursor emulsions and the crosslinking density. The resulting organo-hydrogel displayed favorable antibacterial activity against E. coli and S. aureus. CAA, as the reactive emulsifier and crosslinking agent, was a promising alternative candidate to fabricate a series of organo-hydrogel.
Assuntos
Acetoacetatos/química , Antibacterianos/farmacologia , Celulose/química , Emulsificantes/química , Hidrogéis/química , Óleos de Plantas/farmacologia , Polímeros/química , Thymus (Planta)/química , Acetoacetatos/síntese química , Celulose/síntese química , Quitosana/síntese química , Quitosana/química , Módulo de Elasticidade , Emulsões/química , Escherichia coli/efeitos dos fármacos , Hidrogéis/síntese química , Testes de Sensibilidade Microbiana , Polímeros/síntese química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacosRESUMO
Aerogels that derived from biomass have long been attractive as absorbents for oil clean-up. However, it remains a significant challenge to prepare fully bio-based oil absorbents that combines fast oil/water separation capacity, adequate mechanical robustness and easy recyclability through green and facile strategy. Inspired by the fascinating structure of wood, here we report a highly porous and anisotropic bio-based aerogel by taking advantage of the directional freezing technology, followed by a freeze-drying and silylation process. Due to the directional growth of ice crystals along the vertical direction, a special spring like morphology was obtained, which is mainly composed of well aligned low-tortuosity channels that seamlessly connected to bottom layer. Superior mechanical properties that allow for high mechanical compressing and fast elastic recovery were consequently acquired. Moreover, the silylated CS aerogel displays a rather high oil absorption capacity of 63â¯g g-1, together with excellent recyclability via simple hand squeezing. By virtue of such hierarchical morphology, a device that could continuously separate oil from water was successfully designed. Given the natural abundance of raw material as well as the easy processability, this work would lay solid foundation for further fabrication of bio-based oil absorbents toward low-cost, high-performance and large-scale commodities.
Assuntos
Quitosana/análogos & derivados , Géis/química , Petróleo , Poluentes Químicos da Água/isolamento & purificação , Absorção Fisico-Química , Quitosana/síntese química , Géis/síntese química , Química Verde/métodos , Porosidade , Poluentes Químicos da Água/química , Purificação da Água/métodos , MolhabilidadeRESUMO
In this work, the chemical cross-linked interaction between chitosan polymeric chains and synthetic terephthaloyl diisothiocyanate as a cross-linker was accomplished in order to fabricate three dimensional cross-linked chitosan hydrogel. This cross-linked hydrogel with considerable characteristics including high stability and homogeneity in aqueous solution (water) and high porosity was applied as new substrate for generation of new magnetic terephthaloyl thiourea cross-linked chitosan nanocomposite. The features of this new magnetic nanocomposite were characterized by FT-IR, EDX, FE-SEM, TEM and VSM analysis. The Size distribution of nanoparticles according to the size histogram of FE-SEM images was estimated between 30 and 40â¯nm. The performance of designed magnetic nanocomposite was evaluated by magnetic fluid hyperthermia procedure. Under the alternating magnetic field (AMF), the specific absorption rate (66.92â¯w·g-1) was determined and as well, its saturation magnetization value was reported 78.43â¯emu·g-1.
Assuntos
Quitosana/química , Hidrogéis/química , Nanopartículas de Magnetita/química , Neoplasias/terapia , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Quitosana/síntese química , Quitosana/farmacologia , Humanos , Hidrogéis/síntese química , Hidrogéis/farmacologia , Hipertermia Induzida/métodos , Nanocompostos/química , Ácidos Ftálicos/síntese química , Ácidos Ftálicos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tioureia/síntese química , Tioureia/químicaRESUMO
Creating an appropriate antibacterial disinfection system without forming any harmful compounds is still a major challenge and calls for new technologies for efficient disinfection and microbial control. Towards this aim, we report on the elaboration of biodegradable and biocompatible polymeric nanocapsules, also called hollow nanoparticles, for potential applications in antibiotic therapy. These nanomaterials are based on the self-assembly of charged polysaccharides, namely chitosan and alginate, onto gold nanoparticles as a sacrificial matrix (60 nm). Electrostatic interactions between the protonated amine groups of chitosan (+35 mV) and the carboxylate groups of alginate (- 20 mV) are the driving attraction force enabling the elaboration of well-ordered multilayer films onto the spherical substrate. The removal of the colloidal gold, via cyanide-assisted hydrolysis, is evidenced by time-dependent variation of the gold spectroscopic signature (30 min is required). TEM shows the obtention of nanocapsules. An inhibitory effect of these particles has been demonstrated during the growth of two representative bacteria in a liquid medium: Staphylococcus aureus (Gram-positive) (from 4.6% to 16.3% for gold nanomaterials + and from 18.6% to 34.9% for (chi+/alg-)n-chi+ nanocapsules) and Escherichia coli (Gram-negative) (from 5.4% to 20% for gold nanomaterials and from 23.7% to 40% for (chi+/alg-)n-chi+ nanocapsules). Acridine orange staining demonstrated the bactericidal effect of chitosan-based capsules. These findings demonstrate that (chitosan/alginate)n capsules can be exploited as new antibacterial material. Thus, we present a complementary approach to classical nanoparticles prepared by complexation between alginate and chitosan or other materials.
Assuntos
Antibacterianos/farmacologia , Quitosana/farmacologia , Escherichia coli/efeitos dos fármacos , Ouro/farmacologia , Nanopartículas Metálicas/química , Staphylococcus aureus/efeitos dos fármacos , Alginatos/síntese química , Alginatos/química , Alginatos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Quitosana/síntese química , Quitosana/química , Ouro/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Development of novel biocompatible sensor material suitable for modest, cost-effective, and rapid practical application is a demanding research interest in the field of electroanalytical chemistry. In this context, for the first time, we utilized biocompatible chitosan-pectin biopolyelectrolyte (CS-PC BPE) complex for the simultaneous electroreduction of an important antibiotic drug (metronidazole-MNZ) and herbicide (metribuzin-MTZ). This sensor reveals an attractive welfares such as simplicity, biocompatibility, and low production cost. Under optimized experimental conditions, the electroanalytical investigation confirmed that CS-PC BPE modified glassy carbon electrode (CS-PC BPE/GCE) was found to sense MNZ and MTZ in the nanomolar range. Moreover, as-prepared CS-PC BPE/GCE exhibited prominent selectivity, stability, and reproducibility. Additionally, the possible MNZ and MTZ sensing mechanism of CS-PC BPE/GCE have been discussed in detail. Lastly, real sample analysis was also carried out and revealed from several investigations that the CS-PC BPE/GCE is a good electrochemical sensor system for the detection of targeted analytes.
Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Metronidazol/sangue , Pectinas/química , Polieletrólitos/química , Triazinas/sangue , Antibacterianos/sangue , Antibacterianos/química , Carbono/química , Quitosana/síntese química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Química Verde/métodos , Herbicidas/sangue , Herbicidas/química , Humanos , Limite de Detecção , Metronidazol/química , Peso Molecular , Oxirredução , Pectinas/síntese química , Reprodutibilidade dos Testes , Triazinas/química , ViscosidadeRESUMO
Current phosphate binders used for hyperphosphatemia treatment need large daily dose which make patients' compliance worse and the therapeutic efficacy may not conform the expectation. In this study, three polyacid modified iron-based chitosan derivatives were developed as an oral phosphate binding agent to improve phosphorus adsorption efficacy. The result showed that modification of chitosan by citric acid (CA) could facilitate the conjugation of iron by two folds (272.0⯱â¯12.1-315.3⯱â¯20.5â¯mg Fe/g vs. 141.0⯱â¯4.9-156.5⯱â¯8.3â¯mg Fe/g). All of these iron-based acid-modified chitosan had acceptable safety with cell viability >75% in the concentration up to 250⯵g/mL. The stability in terms of iron release in pH 1.0 for 2â¯h was in the order of DPCS-NAc-CA-Fe (8.9⯱â¯2.3%)â¯<â¯DPCS-CA-Fe (19.1⯱â¯4.1%)â¯<â¯DADPCS-CA-Fe (24.6⯱â¯2.6%) indicating DPCS-NAc-CA-Fe was the most stable one. These iron-based acid-modified chitosan derivatives efficiently adsorbed 255.7⯱â¯11.3-271.2⯱â¯19.3â¯mg of phosphate especially in simulated gastro pH 1.0 in vitro. Furthermore, oral administration of DPCS-NAc-CA-Fe significantly lowered serum phosphorus level from 5.82⯱â¯0.45â¯mg/dL to 4.84⯱â¯0.56â¯mg/dL (pâ¯<â¯0.01) at 0.25% low feeding dose for 3 weeks without losing of weight, appetite, and activity of Wistar rats.