Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 19.628
Filtrar
1.
J Environ Manage ; 261: 110225, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148295

RESUMO

Concrete is significant for construction. A problem in application is the appearance of cracks that will damage its strength. An autogenous crack-healing mechanism based on bacteria receives increasing attention in recent years. The bacteria are able to form calcium carbonate (CaCO3) precipitations in suitable conditions to protect and reinforce the concrete. However, a large number of spores are crushed in aged specimens, resulting in a loss of viability. A new kind of hydrogel crosslinked by alginate, chitosan and calcium ions was introduced in this study. It was observed that the addition of chitosan improved the swelling properties of calcium alginate. Opposite pH response to calcium alginate was observed when the chitosan content in the solution reached 1.0%. With an addition of 1.0% chitosan in hydrogel beads, 10.28% increase of compressive strength and 13.79% increase of flexural strength to the control were observed. The results reveal self-healing properties of concretes. A healing crack of 4 cm length and 1 mm width was observed when using cement PO325, with the addition of bacterial spores (2.54-3.07 × 105/cm3 concrete) encapsulated by hydrogel containing no chitosan.


Assuntos
Quitosana , Hidrogéis , Bactérias , Carbonato de Cálcio , Materiais de Construção , Concentração de Íons de Hidrogênio
2.
Sheng Wu Gong Cheng Xue Bao ; 36(2): 332-340, 2020 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-32148005

RESUMO

In order to further improve the hemostatic performance of wound dressings, human platelet-rich plasma (PRP) containing various growth factors was introduced into chitosan solution. The silk fibroin solutions with different volume ratios (1:1, 1:3, 3:1 and 1:0) were added to improve the porosity and hemostasis of materials. The hPRP-chitosan/silk wound dressings with different ratios was prepared by freeze-drying and pure chitosan dressing was considered as the control group to study the effects of PRP and silk fibroin in different proportions on the hemostasis properties and the growth factors burst release. The hemostasis of chitosan dressing was improved by introducing PRP, but the porous structure and water absorption were not significantly improved. If silk fibroin solution was added in the ratio of 1:1, the more uniform porous structure and better hemostatic performance could be obtained. The porosity and water absorption could reach 86.83%±3.84% and 1 474%±114% respectively. In addition, the dressings with ratio of 1:1 had positive effects on reducing the burst release of growth factors on initial stage. Therefore, PRP-chitosan/silk fibroin composite dressing can become a kind of wound dressing that can achieve rapid hemostasis and promote wound healing.


Assuntos
Bandagens , Hemostáticos , Quitosana , Fibroínas , Hemostasia , Humanos , Plasma Rico em Plaquetas , Porosidade
3.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(1): 10-17, 2020 Feb 18.
Artigo em Chinês | MEDLINE | ID: mdl-32071457

RESUMO

OBJECTIVE: To prepare glycol-chitosan (GC)-based single/dual-network hydrogels with different composition ratios (GC31, DN3131 and DN6262) and to investigate the effects of hydrogel scaffolds on biological behavior of human dental pulp cell (hDPC) encapsulated. METHODS: GC-based single-network hydrogels (GC31) and GC-based dual-network hydrogels (DN3131, DN6262) with different composition ratios were prepared. The injectability was defined as the average time needed to expel a certain volume of hydrogel under a constant force. The degradation of the hydrogel was determined by the weight loss with time. The fracture stress was measured using a universal testing machine. The proliferation of hDPCs in hydrogels was detected using the cell counting kit-8 (CCK-8) method and CalceinAM/PI Live/Dead assay. After 14 days of odontoblastic induction, the expression of alkaline phosphatase (ALP), dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) was detected by real-time quantitative reverse transcription PCR (real-time RT-PCR) and the mineralized nodules was observed by Von Kossa staining. RESULTS: The injectability of all three groups of hydrogels was acceptable. The time of injection of GC31 was the shortest, and that of DN6262 was longer than DN3131 (P<0.05). The degradation rate of GC31 hydrogel in vitro was significantly faster than that of the dual-network hydrogel groups (P<0.05). There was no significant difference between DN3131 and DN6262 (P>0.05). The compressive resistance failure point of GC31 group was 1.10 kPa, while it was 7.33 kPa and 43.30 kPa for DN3131 and DN6262. The compressive strength of dual-network hydrogel was significantly enhanced compared with single-network hydrogel. hDPCs were in continuous proliferation in all the three groups, and the GC31 group showed a higher proliferation rate (P<0.05). The expression levels of DSPP, DMP-1 and ALP in the dual-network hydrogel groups (DN3131, DN6262) were significantly higher than that of GC31 after culturing for 14 days (P<0.05), there was no difference in the expression levels of DMP-1 and ALP between DN3131 and DN6262 (P>0.05); Von Kossa staining showed that more mineralization deposition and mass-shaped mineralized nodules formed in DN3131 and DN6262, while only light brown calcium deposition staining was observed in GC31 group, which was scattered in granular forms. CONCLUSION: GC-based single/dual network hydrogels with different composition ratios met the injectable requirements. GC31 group had a lower mechanical properties, in which hDPCs exhibited a higher proliferation rate. dual-network hydrogels had slower degradation rate and higher mechanical properties, in which hDPCs exhibited better odontoblastic differentiation potential and mineralization potential.


Assuntos
Polpa Dentária , Hidrogéis , Fosfatase Alcalina , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Quitosana , Humanos , Odontoblastos
4.
J Photochem Photobiol B ; 204: 111809, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32062390

RESUMO

The graphene oxide (GO)-based materials are appealing channels for water treatment, their separation from water for recycle remains a task. The Cu3(btc)2 (btc = benzene-1,3,5-tricarboxylic acid) metal organic framework (MOF) was covalently immobilized onto chitosan (CS)/graphene oxide (GO) to form a catalyst material, which was subjected to characterization by XRD, FTIR, SEM, TEM, BET, and UV-vis diffusive reflectance spectra. MOFs are permeable crystalline compounds consisting of metal ions and polyfunctional organic ligands. The structural characterization revealed that the Cu3(btc)2 and chitosan were incorporated into the graphene oxide structure. The adsorption of MB by GO-CS@Cu3(btc)2 catalyst was clearly defined by Langmuir isotherm and pseudosecond order kinetic model. GO-CS@Cu3(btc)2 was found to possess an adsorption capacity of ~357.15 mg/g. The findings displayed the probability of reusing the catalyst material for several photocatalytic processes. The GO-CS@Cu3(btc)2 catalyst material exhibited 98% degradation of MB within 60 min under UV irradiation. The obtained MB degradation results were fitted onto a Langmuir-Hinshelwood (L-H) plot. The GO-CS@Cu3(btc)2 catalyst material exhibited high degradation efficiencies at neutral pH conditions. The results have shown that the GO-CS@Cu3(btc)2 catalyst material can be used as a catalyst for adsorption and as a photocatalyst for the efficient degradation of methylene blue from aqueous solutions.


Assuntos
Quitosana/química , Complexos de Coordenação/química , Grafite/química , Azul de Metileno/química , Adsorção , Catálise , Cobre/química , Concentração de Íons de Hidrogênio , Cinética , Fotólise/efeitos da radiação , Raios Ultravioleta
5.
DNA Cell Biol ; 39(3): 451-458, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31910350

RESUMO

Gene delivery from tissue engineering scaffold is a novel strategy in regulating long-term growth and function of cells in vitro culture. In this study, a hepatocyte growth factor plasmid/polyetherimide (pHGF/PEI) polyplex delivering alginate (AL)/galactosylated chitosan (GC) (pHGF/PEI-AL/GC) sponge scaffold was prepared for the in vitro coculture of hepatocytes/3T3 cells. The pHGF/PEI polyplex released for 6 days in the sponge scaffold with weight ratio of AL/GC being 3:1 and fixed amount of pHGF being 40 µg (24-well scaffold). In addition, the 3T3 cells culturing in the pHGF/PEI-AL/GC sponge scaffold could be continually transfected and expressed the exogenous HGF for 6 days. Furthermore, the albumin secretion and urea synthesis of hepatocytes were significantly enhanced when cocultured with 3T3 cells in the pHGF/PEI-AL/GC sponge scaffold compared with that in the AL/GC sponge without pHGF. In summary, the preparation of AL/GC sponge scaffold delivering pHGF/PEI polyplex is a critical significance for maintaining the long-term survival and function of primary hepatocytes in vitro.


Assuntos
Quitosana/análogos & derivados , Técnicas de Transferência de Genes , Fator de Crescimento de Hepatócito/metabolismo , Hepatócitos/metabolismo , Tecidos Suporte/química , Células 3T3 , Alginatos/química , Animais , Células Cultivadas , Técnicas de Cocultura/métodos , Galactose/análogos & derivados , Fator de Crescimento de Hepatócito/genética , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Masculino , Camundongos , Polímeros/química , Ratos , Ratos Wistar , Tecidos Suporte/efeitos adversos
6.
AAPS PharmSciTech ; 21(2): 43, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897806

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) is considered a common colonizer of burn wound and accounts for high morbidity and mortality all across the globe. Systemic antibiotic therapy which is generally prescribed for these patients has a number of limitations. These include high drug dose, toxicity, and chances of development of drug resistance. However, local delivery of drug not only addresses these limitations but also provides better efficacy at the site of infection. In the present study, hydrogel preparations were developed for the topical delivery of moxifloxacin for the treatment of S. aureus-infected burn wound. Moxifloxacin was characterized by UV, FTIR, DSC, hot-stage microscopy, NMR, and HPLC and loaded into conventional and Boswellia-containing novel gels. Gels were characterized by visual examination, pH, UV spectroscopy, and release assays. In vivo studies showed that both gels were effective in eradicating the bacteria completely from the wound site when treatment was started during the early stage of infection. On the contrary, delayed treatment of planktonic and biofilm cells with novel gel showed better efficacy as compared with conventional gel in S. aureus-infected burn wound. Histopathological analysis also showed better skin healing efficacy of novel gel than conventional gel. Our results show that moxifloxacin can be efficiently used topically in the management of burn wound infections along with other antibacterial agents. Since biofilm-mediated infections are on the rise especially in chronic bacterial disease, therefore, a preparation containing antibiofilm agent-like Boswellia as one of the excipients would be more meaningful.


Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Anti-Infecciosos Locais/administração & dosagem , Anti-Infecciosos Locais/farmacologia , Biofilmes/efeitos dos fármacos , Queimaduras/complicações , Quitosana/química , Hidrogéis/química , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Animais , Antibacterianos/química , Anti-Infecciosos Locais/química , Boswellia/química , Composição de Medicamentos , Géis , Staphylococcus aureus Resistente à Meticilina , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Moxifloxacina/administração & dosagem , Moxifloxacina/química , Moxifloxacina/uso terapêutico , Infecções Estafilocócicas/microbiologia , Infecção dos Ferimentos/microbiologia
7.
J Environ Manage ; 256: 109969, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31989986

RESUMO

This study reports a new inorganic-organic composite membrane fabricated by an electrostatic self-assembling method. The low-cost and eco-friendly porous geopolymer (PG) was chosen as a support, on which chitosan (CS), a "green" biomaterial, was used to form an active layer. With optimum dosage of CS (2.0 mL of 1.0% CS solution), the obtained CS/PG membrane exhibited a high porosity of 50.97% with an average pore diameter of 13.93 nm as well as a high water flux of 1663.82 ± 22.46 L/m2·h·bar. The effects of initial concentration, pH, flow rate and temperature of the feed solution on crystal violet (CV) removal by the CS/PG were evaluated in a continuous mode. The results indicated ~95% CV could be removed from water during continuous treating of 14 h. The effectiveness in CV removal by the CS/PG membrane was attributed to the synergistic effect of rejection and adsorption. Furthermore, the composite membrane could be easily regenerated for prolonged use. Overall, this work opens a new possibility of building cost-saving and eco-friendly composite membranes for practical applications in water purification.


Assuntos
Quitosana , Poluentes Químicos da Água , Purificação da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética
8.
J Environ Manage ; 258: 110043, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929075

RESUMO

Two types of chitosan-based composites (chitosan/ZnO and chitosan/Ce-ZnO composites) were synthesized under microwave irradiation and characterized as advanced catalysts of enhanced photocatalytic activity under the visible light. The morphological investigation reflected the formation of ZnO and Ce doped ZnO at stunning micro flowers of nano limps. Additionally, the optical studies reflected a reduction in the bandgap of ZnO from 3.3 eV to 2.85 eV and 2.5 eV after supporting it onto chitosan chains and after doping it with cerium, respectively. The synthetic composites were applied in photocatalytic removal of malachite green dye under a visible light source. The synthetic CH/ZnO and CH/Ce-ZnO showed enhancement in the photocatalytic removal of M.G by 54% and 87%, respectively, as compared to the pure ZnO. The synthetic composites are of high stability and can be reused for five photocatalytic degradation cycles at stunning removal percentages. The main oxidizing radicals during the removal of M.G by CH/ZnO are the generated electron-hole pairs as well as the hydroxyl radicals. The effective species in CH/Ce-ZnO photocatalytic system are the photogenerated hydroxyl radicals followed by the electron-hole pairs.


Assuntos
Quitosana , Óxido de Zinco , Flores , Luz , Corantes de Rosanilina
9.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 34(1): 102-108, 2020 Jan 15.
Artigo em Chinês | MEDLINE | ID: mdl-31939244

RESUMO

Objective: To evaluate the feasibility of the chitosan-poly (lactide-co-glycolide) (PLGA) double-walled microspheres for sustained release of bioactive nerve growth factor (NGF) in vitro. Methods: NGF loaded chitosan-PLGA double-walled microspheres were prepared by emulsion-ionic method with sodium tripolyphosphate (TPP) as an ionic cross-linker. The double-walled microspheres were cross-linked by different concentrations of TPP [1%, 3%, 10% ( W/ V)]. NGF loaded PLGA microspheres were also prepared. The outer and inner structures of double-walled microspheres were observed by light microscopy, scanning electron microscopy, confocal laser scanning microscopy, respectively. The size and distribution of microspheres and fourier transform infra red spectroscopy (FT-IR) were analyzed. PLGA microspheres with NGF or chitosan-PLGA double-walled microspheres cross-linked by 1%, 3%, and 10%TPP concentration (set as groups A, B, C, and D respectively) were used to determine the degradation ratio of microspheres in vitro and the sustained release ratio of NGF in microspheres at different time points. The bioactivity of NGF (expressed as the percentage of PC12 cells with positive axonal elongation reaction) in the sustained release solution of chitosan-PLGA double-walled microspheres without NGF (set as group A1) was compared in groups B, C, and D. Results: The chitosan-PLGA double-walled microspheres showed relative rough and spherical surfaces without aggregation. Confocal laser scanning microscopy showed PLGA microspheres were evenly uniformly distributed in the chitosan-PLGA double-walled microspheres. The particle size of microspheres ranged from 18.5 to 42.7 µm. The results of FT-IR analysis showed ionic interaction between amino groups and phosphoric groups of chitosan in double-walled microspheres and TPP. In vitro degradation ratio analysis showed that the degradation ratio of double-walled microspheres in groups B, C, and D appeared faster in contrast to that in group A. In addition, the degradation ratio of double-walled microsphere in groups B, C, and D decreased when the TPP concentration increased. There were significant differences in the degradation ratio of each group ( P<0.05). In vitro sustained release ratio of NGF showed that when compared with PLGA microspheres in group A, double-walled microspheres in groups B, C, and D released NGF at a relatively slow rate, and the sustained release ratio decreased with the increase of TPP concentration. Except for 84 days, there was significant difference in the sustained release ratio of NGF between groups B, C, and D ( P<0.05). The bioactivity of NGF results showed that the percentage of PC12 cells with positive axonal elongation reaction in groups B, C, and D was significantly higher than that in group A1 ( P<0.05). At 7 and 28 days of culture, there was no significant difference between groups B, C, and D ( P>0.05); at 56 and 84 days of culture, the percentage of PC12 cells with positive axonal elongation reaction in groups C and D was significantly higher than that in group B ( P<0.05), and there was no significant difference between groups C and D ( P>0.05). Conclusion: NGF loaded chitosan-PLGA double-walled microspheres have a potential clinical application in peripheral nerve regeneration after injury.


Assuntos
Microesferas , Animais , Quitosana , Dioxanos , Fator de Crescimento Neural , Tamanho da Partícula , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Photochem Photobiol B ; 203: 111773, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31931385

RESUMO

Glioma is the prime cause of cancer allied mortality in adolescent people and it accounts about 80% of all malignant tumours. Eugenol is a major bioactive constituent present in the essential oils with numerous pharmacological benefits including nueroprotective activity. The major drawback of eugenol is its extreme volatile property and oxygen sensitivity therefore we increased the efficacy of drug; eugenol by encapsulating with chitosan polymer. Eugenol loaded chitosan polymer (EuCs) was characterized using FTIR, XRD, SEM, HR-TEM analysis and the encapsulation, drug release efficacy was assessed at in vitro condition. The induction of autophagy and anticancer efficacy of EuCs on glioma cells was evaluated with rat C6 glioma cells using MTT assay, acridine orange staining, immunocytochemical analysis of NFκß protein expression and FLOW cytometric analysis. The anti-metastatic property of Eu-CS was assessed by immunoblotting and RT-PCR analysis of epithelial mesenchymal transition protein expression in EuCs treated rat C6 glioma cells. Our characterization analysis proves that EuCs possess essential physical and functional properties of copolymer to be utilized as a drug. Further the MTT analysis and AO staining confirms even in the presence of oncogenic inducer and autophagic inhibitors, EuCs exhibits apoptotic potency on rat C6 glioma cells. The result of immunocytochemical studies depicts the inhibition of NFκß protein expression and flow cytometry studies confirm apoptosis induction by EuCs. The inhibition of metastasis by EuCs was proven by the decrease in epithelial mesenchymal transition protein expression in Eu-Cs treated rat C6 glioma cells. Over all our results authentically confirms eugenol loaded chitosan nanopolymer persuasively induces apoptosis and inhibits metastasis in rat C6 glioma cells.


Assuntos
Antineoplásicos/química , Apoptose/efeitos dos fármacos , Quitosana/química , Eugenol/química , Metaloproteinase 9 da Matriz/metabolismo , Nanoestruturas/química , Transdução de Sinais/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Portadores de Fármacos/química , Eugenol/farmacologia , Glioma/metabolismo , Glioma/patologia , NF-kappa B/metabolismo , Ratos , Ativador de Plasminogênio Tipo Uroquinase/metabolismo
11.
J Biomed Nanotechnol ; 16(1): 101-110, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31996289

RESUMO

Large (> 6 mm) artificial blood vessels have been successfully employed in clinic practice. However, small-diameter (< 6 mm) synthetic grafts have not been applied due to their hydrophobicity. In this study, poly-vinylpyrrolidone (PVP) was introduced into poly-L-lactic acid (PLLA) to prepare biodegradable small-diameter electrospun blood vessels which were further modified via electrostatic self-assembly (ESA). The characteristics of PLLA/PVP films were investigated by scanning electron microscopy (SEM), contact angle measurement and mechanical property testing. The cytocompatiblility and blood compatibility of the fiber films were further studied through vascular smooth muscle cells (VSMCs) proliferation and platelet adhesion, and the morphology of cells on films was viewed by laser scanning confocal microscopy (LSCM) and SEM. Next, the surface of ESA-modified electrospun fiber films was analyzed through SEM and photoelectron spectroscopy (XPS). The degradation characteristics of these films were investigated through SEM observation, weight loss, viscosity average molecular weight reduction, and pH change in the testing solutions as well. The films were also subcutaneously implanted in rabbits to analyze the biocompatibility. The results of these experiments showed that electrospun films with PVP possessed a good structure and improved hydrophilicity. The films assembled with chitosan/heparin by ESA were beneficial to VSMCs survival and had excellent blood compatibilities. The data indicated these films were biodegradable with good tissue compatibility. In conclusion, we successfully obtained biodegradable small-diameter blood vessels through electrospinning PLLA/PVP and modifying this blend's surface using ESA. The study provided a feasible method for making small-diameter synthetic blood vessels with improved hydrophilic and anticoagulant properties.


Assuntos
Substitutos Sanguíneos/química , Animais , Materiais Biocompatíveis , Quitosana , Poliésteres , Polímeros , Coelhos , Propriedades de Superfície
12.
J Agric Food Chem ; 68(6): 1698-1706, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31986048

RESUMO

Proteins of pea whey were separated by 1-D electrophoresis and 2-D electrophoresis and identified by MALDI-TOF/TOF-MS. In addition to lectin, pea albumin 2 (PA2) and pea albumin 1a (PA1a) were identified as the main 2S albumins. The complex behavior of pea whey proteins with chitosan as a function of pH and protein to polysaccharide ratio was studied by turbidimetric titration, zeta potential, and Tricine-SDS-PAGE. During pH titration, the zeta potential reveals that at maximum turbidity (pHmax), charge neutrality was fulfilled. The maximal protein recovery was obtained at a mass ratio of 1:1. After coacervation with chitosan, lectin was not involved in the formation of complexes and PA2 transferred into complex preferentially as compared to PA1a. The weak binding affinity and high hydrophilicity of PA1a made it selectively dissolve out from the PA2/PA1a complex at acidic pH conditions. After removal of chitosan and small molar weight peptides, high-purity PA2 and PA1a (>90% by SEC-HPLC) could be obtained. This work provides a novel strategy for the purification of proteins from a multiprotein pea whey system.


Assuntos
Albuminas/química , Quitosana/química , Proteínas de Ervilha/química , Ervilhas/química , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Ligação Proteica
13.
J Photochem Photobiol B ; 204: 111780, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31981988

RESUMO

Photothermal therapy (PTT) is recently clinically established cancer therapy that uses near-infrared light for thermal ablation of solid tumors. The biopolymer N-dihydrogalactochitosan (GC) was shown in multiple reports to act as a very effective adjunct to tumor PTT. In the present study, mouse tumor model SCCVII (squamous cell carcinoma) was used with two protocols, in situ tumor PTT and therapeutic PTT vaccine for tumors, for investigating the effects of GC. The results reveal that GC can potentiate tumoricidal action of PTT through both direct and indirect mechanisms. In addition to previously known capacity of GC for activating immune effector cells, the indirect means is shown to include reducing the populations of immunoregulatory T cells (Tregs) in PTT-treated tumors. Testing the effects of GC on PTT-treated SCCVII tumor cells in vitro uncovered the existence of a direct mechanism evident by reduced colony survival of these cells. Fluorescence microscopy demonstrated increased binding of fluorescein-labeled GC to PTT-treated compared to untreated SCCVII cells that can be blocked by pre-exposure to annexin V. The results of additional in vitro testing with specific inhibitors demonstrate that these direct mechanisms do not involve the engagement of death surface receptors that trigger extrinsic apoptosis pathway signaling but may be linked to pro-survival activity of caspase-1. Based on the latter, it can be suggested that GC-promoted killing of PTT-treated cells stems from interference of GC bound to damaged membrane components with the repair of these structures that consequently hinders cell survival.


Assuntos
Quitosana/química , Lasers Semicondutores , Fototerapia/métodos , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Caspase 1/química , Caspase 1/metabolismo , Inibidores de Caspase/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Quitosana/farmacologia , Modelos Animais de Doenças , Proteína Ligante Fas/metabolismo , Fluoresceína/química , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Camundongos , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/efeitos dos fármacos , Receptor fas/metabolismo
14.
J Appl Oral Sci ; 28: e20190005, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31800870

RESUMO

other: Chitosan is a natural, biocompatible chelating substance with potential for dental use. This study compared the effects of final canal irrigation with chitosan and EDTA on dentin microhardness, sealer dentin tubules penetration capacity, and push-out strength. METHODOLOGY: Fifty canine roots were distributed according to the final irrigation protocol (n=10): G1- 15% EDTA with conventional irrigation; G2- 15% EDTA with Endovac; G3- 0.2% chitosan with conventional irrigation; G4- 0.2% chitosan with Endovac; and G5- without irrigation. Specimens were obturated (AH Plus) and sectioned in 3 slices per root third. The first slice was used for microhardness and sealer penetration assessments under a laser confocal microscope. The second was utilized in a push-out strength test. The third slice was discarded. Data were analyzed using 2-way ANOVA and Tukey's post hoc test (α<0.05). Failure mode was determined at x40 magnification. RESULTS: Microhardness reduction was more significant in groups G2 and G4 (p<0.05). Sealer penetration through dentin was significantly greater in group G2 (p<0.05). There was no significant difference between groups G1, G3, and G4 (p>0.05). In general, all experimental groups presented similar bond resistance (p>0.05) that significantly differed from the control (p<0.001). Mixed type failures were predominant. CONCLUSIONS: In general, 0.2% chitosan and 15% EDTA solutions act in a similar manner with regard to the variables studied. The use of Endovac potentiates the effect of these solutions.


Assuntos
Quelantes/química , Quitosana/química , Colagem Dentária/métodos , Dentina/efeitos dos fármacos , Ácido Edético/química , Irrigantes do Canal Radicular/química , Análise de Variância , Resinas Epóxi/química , Testes de Dureza , Humanos , Teste de Materiais , Microscopia Confocal , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Materiais Restauradores do Canal Radicular/química , Resistência ao Cisalhamento , Propriedades de Superfície/efeitos dos fármacos
15.
Anal Bioanal Chem ; 412(2): 499-506, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31807805

RESUMO

Although a massive research has been devoted on the exploration of noble metal-based nanozyme, less progress has been made in the investigation of palladium (Pd) nanozyme and the interaction between ions and Pd nanozyme. In this study, a new type of Pd nanozyme was prepared by a facile one-pot approach by using carboxylated chitosan as the stabilizer. Owing to the synergistic effect of carboxylated chitosan stabilized Pd nanoparticles (CC-PdNPs) can effectively catalyze the H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine sulfate (TMB) accompanied by a blue color change (oxidized TMB), indicating the peroxidase-like activity of CC-PdNPs. Furthermore, the Michaelis-Menten constants and catalytic stability of CC-PdNPs render them suitable for environmental analysis and bio-detection. Here, we found that while introducing the iodine ions (I-) into the reaction medium, the peroxidase-like activity of CC-PdNPs has been rapidly and effectively inhibited through the formation of Pd-I bond; thus, the active sites of PdNPs can be blocked by I-. Based on this specific inhibition by I-, a facile colorimetric assay has been performed for the detection of I- with an extremely low limit of detection (0.19 nM). Furthermore, the practicality of the proposed sensor also has been demonstrated in tap water, and the satisfactory recoveries were obtained. Our study not only demonstrated a novel Pd-based nanozyme but also provided guidance for I- sensing for environmental analysis, food inspection, and bio-detection. Graphical abstract.


Assuntos
Ácidos Carboxílicos/química , Quitosana/química , Colorimetria/instrumentação , Enzimas/química , Iodo/análise , Nanoestruturas/química , Paládio/química , Ânions , Limite de Detecção , Abastecimento de Água
16.
J Photochem Photobiol B ; 202: 111721, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31790881

RESUMO

The present study clearly demonstrated the significant antifungal activity of chlorophyllin-chitosan complex (Chl-CHS) after activation with visible light. This phenomenon afterwards was successfully applied for better microbial control of highly popular food- germinated wheat sprouts. Obtained results indicated that photoactivated Chl-CHS complex (0.001% Chl-0.1% CHS and 0.005% Chl-0.5% CHS, 405 nm, 76 J/cm2) considerably inhibited (83%) the growth of dominating sprout pathogenic microfungus Fusarium graminearum in vitro. Moreover, obvious delay of fungus growth by 4 days after treatment was observed. The efficiency of antifungal treatment strongly depended on used Chl-CHS complex concentration. The coating of wheat grains with Chl-CHS (0.005% Chl-0.5% CHS) and illumination with visible light (405 nm; 76 J/cm2) inactivated the molds on the surface of grains by 79%. It is important to note, that no grain surface microstructure damage observed by SEM imaging have been found. No inhibiting effects on seed germination process, viability, average weight of grains, length of seedlings and content of chlorophyll a and chlorophyll b in the seedlings or eventually visual quality after Chl-CHS coating of grains and illumination with visible light have been observed. In conclusion, chlorophyllin-chitosan coating in the concert with visible light has great potential as cost-effective, environmentally friendly and sustainable strategy for better microbial control of highly contaminated sprouts.


Assuntos
Antifúngicos/química , Quitosana/química , Clorofilídios/química , Fusarium/efeitos dos fármacos , Luz , Triticum/microbiologia , Antifúngicos/farmacologia , Fusarium/efeitos da radiação , Germinação/efeitos dos fármacos , Germinação/efeitos da radiação , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Triticum/crescimento & desenvolvimento
17.
J Chromatogr A ; 1609: 460509, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31515076

RESUMO

A simple and efficient sample preparation method to extract four bioactive compounds (echinacoside, specnuezhenide, oleuropein and nuezhenoside G13) from Ligustri Lucidi Fructus was established by vortex-forced matrix solid phase dispersion (VFMSPD) method. Chitosan solution was applied as green eluent in this procedure and Celite AZO was employed as dispersant. High performance liquid chromatography (HPLC) equipped with ultraviolet (UV) detector was used to analyze the target analytes. The best result of the investigation was obtained with Celite AZO as dispersant, sample/ dispersant ratio as 1:1, grinding for 2 min, 1 mL high-viscosity chitosan solution (0.5 mg mL-1) used as the elution reagent and vortex mixing for 1.5 min. The method exhibit a good linearity for the analytes (r2 > 0.999). The absolute recoveries of the four target compounds in Ligustri Lucidi Fructus ranged from 90.7% to 98.8% and the relative recoveries of the target compounds ranged from 99.2% to 102% (RSD ≤ 3.4%), which were obtained by the final optimization method. Consequently, the newly developed chitosan solution-based vortex-forced matrix solid phase dispersion (MSPD) combined with HPLC could be efficiently applied to extract and analyze the target compounds in Ligustri Lucidi Fructus samples.


Assuntos
Quitosana/química , Cromatografia Líquida de Alta Pressão/métodos , Ligustrum/química , Compostos Fitoquímicos/análise , Extração em Fase Sólida/métodos , Frutas/química , Compostos Fitoquímicos/química , Padrões de Referência , Reprodutibilidade dos Testes , Soluções , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Clin Oral Investig ; 24(1): 437-446, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31104110

RESUMO

OBJECTIVES: Τhis study aims at determining the ability of cone beam computed tomography (CBCT) to visualize critical-size defects (CSD) created at rat calvaria and filled with 75/25 w/w nano-hydroxyapatite/chitosan (nHAp/CS) scaffolds, prior to their histological investigation. MATERIALS AND METHODS: Thirty adult Sprague Dawley rats, 15 males and 15 females, were used. Two CSD, 5 mm in diameter, were bilaterally trephined in the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. Two female rats died post-operatively. Rats were euthanized at 2, 4, and 8 weeks post-surgery. Twenty-eight specimens (15 × 2 × 10 mm) were resected-containing both CSDs-and then scanned using a NewTom VGi CBCT imaging unit (Verona, Italy). The manufacturer's software trace region profile tool (NNT v6.2, Verona, Italy) was used in selected axial slices. The greyscale value (in VGiHU) and the traced/selected region of interest (ROI, in mm2) of those areas were automatically calculated. Subsequently, all specimens were histologically examined. RESULTS: An increased VGiHU (P = 0.000), was observed in the experimental group relative to the control group. The ROI of CSD (in mm2) was significantly reduced (P = 0.001) from the fourth to the eighth week in both groups. No statistically significant difference between male and female rats (P = 0.188) was observed with respect to VGiHU. CONCLUSIONS: The nHAp/CS scaffolds are easily visualized using a particular high-resolution CBCT device. CLINICAL RELEVANCE: Both the CBCT measurements and also the histological results suggest that the nHAp/CS scaffold presence contributes to new bone formation in rat calvarial CSD.


Assuntos
Quitosana , Tomografia Computadorizada de Feixe Cônico , Durapatita , Animais , Feminino , Itália , Masculino , Ratos , Ratos Sprague-Dawley , Crânio/diagnóstico por imagem , Crânio/patologia
19.
Clin Oral Investig ; 24(2): 663-674, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31119382

RESUMO

OBJECTIVES: This study aimed to develop a porous chitosan-calcium-aluminate scaffold (CH-AlCa) in combination with a bioactive dosage of 1α,25-dihydroxyvitamin D3 (1α,25VD), to be used as a bioactive substrate capable to increase the odontogenic potential of human dental pulp cells (HDPCs). MATERIALS AND METHODS: The porous CH-AlCa was developed by the incorporation of an AlCa suspension into a CH solution under vigorous agitation, followed by phase separation at low temperature. Scaffold architecture, porosity, and calcium release were evaluated. Thereafter, the synergistic potential of CH-AlCa and 1 nM 1α,25VD, selected by a dose-response assay, for HDPCs seeded onto the materials was assessed. RESULTS: The CH-AlCa featured an organized and interconnected pore network, with increased porosity in comparison with that of plain chitosan scaffolds (CH). Increased odontoblastic phenotype expression on the human dental pulp cell (HDPC)/CH and HDPC/CH-AlCa constructs in the presence of 1 nM 1α,25VD was detected, since alkaline phosphatase activity, mineralized matrix deposition, dentin sialophosphoprotein/dentin matrix acidic phosphoprotein 1 mRNA expression, and cell migration were overstimulated. This drug featured a synergistic effect with CH-AlCa, since the highest values of cell migration and odontoblastic markers expression were observed in this experimental condition. CONCLUSIONS: The experimental CH-AlCa scaffold increases the chemotaxis and regenerative potential of HDPCs, and the addition of low-dosage 1α,25VD to this scaffold enhances the potential of these cells to express an odontoblastic phenotype. CLINICAL RELEVANCE: Chitosan scaffolds enriched with calcium-aluminate in association with low dosages of 1α,25-dihydroxyvitamin D3 provide a highly bioactive microenvironment for dental pulp cells prone to dentin regeneration, thus providing potential as a cell-free tissue engineering system for direct pulp capping.


Assuntos
Polpa Dentária , Cálcio , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Quitosana , Humanos , Odontoblastos , Tecidos Suporte
20.
Appl Biochem Biotechnol ; 190(1): 148-165, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31313241

RESUMO

Feasibility and stability were evaluated of a continuous multi-batch process for converting oleuropein (OLE) from olive leaf extract to the bioactive product hydroxytyrosol (HT). Carrier beads made of three different materials (calcium alginate, chitosan with deacetylated α-chitin nanofibers (DEChN), or porous ceramic) were investigated for morphology, thermogravimetric, sorption, and viscoelastic properties. Enzymatic hydrolysis of OLE conducted in a packed bed bioreactor containing cellulase immobilized to carrier beads yielded OLE degradation rates of ~ 90% and an average HT yield of ~ 70% over 20 batches. Ultimately, inorganic porous ceramic beads were less costly and exhibited superior performance relative to organic carriers and thus were deemed most suitable for industrial-scale HT production. Systems utilizing enzyme immobilization within packed bed reactors hold promise for achieving efficient production of valuable bioproducts from discarded biomass materials.


Assuntos
Celulase/metabolismo , Enzimas Imobilizadas/metabolismo , Iridoides/metabolismo , Olea/metabolismo , Álcool Feniletílico/análogos & derivados , Folhas de Planta/metabolismo , Alginatos/química , Biomassa , Reatores Biológicos , Cerâmica , Quitosana/química , Hidrólise , Microscopia Eletrônica de Varredura , Álcool Feniletílico/metabolismo , Especificidade por Substrato , Termogravimetria
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA