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1.
J Appl Oral Sci ; 28: e20190516, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236357

RESUMO

INTRODUCTION: This study investigated the effect of a calcium hydroxide (CH) paste (CleaniCal®) containing N-2-methyl pyrrolidone (NMP) as a vehicle on Enterococcus faecalis (E. faecalis) biofilms compared with other products containing saline (Calasept Plus™) or propylene glycol (PG) (Calcipex II®). METHODOLOGY: Standardized bovine root canal specimens were used. The antibacterial effects were measured by colony-forming unit counting. The thickness of bacterial microcolonies and exopolysaccharides was assessed using confocal laser scanning microscopy. Morphological features of the biofilms were observed using field-emission scanning electron microscopy (FE-SEM). Bovine tooth blocks covered with nail polish were immersed into the vehicles and dispelling was observed. The data were analyzed using one-way analysis of variance and Tukey tests (p<0.05). RESULTS: CleaniCal® showed the highest antibacterial activity, followed by Calcipex II® (p<0.05). Moreover, NMP showed a higher antibacterial effect compared with PG (p<0.05). The thickness of bacteria and EPS in the CleaniCal® group was significantly lower than that of other materials tested (p<0.05). FE-SEM images showed the specimens treated with Calasept Plus™ were covered with biofilms, whereas the specimens treated with other medicaments were not. Notably, the specimen treated with CleaniCal® was cleaner than the one treated with Calcipex II®. Furthermore, the nail polish on the bovine tooth block immersed in NMP was completely dispelled. CONCLUSIONS: CleaniCal® performed better than Calasept Plus™ and Calcipex II® in the removal efficacy of E. faecalis biofilms. The results suggest the effect might be due to the potent dissolving effect of NMP on organic substances.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Hidróxido de Cálcio/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Pirrolidinonas/farmacologia , Irrigantes do Canal Radicular/farmacologia , Análise de Variância , Animais , Cloreto de Cálcio/química , Cloreto de Cálcio/farmacologia , Hidróxido de Cálcio/química , Bovinos , Contagem de Colônia Microbiana , Combinação de Medicamentos , Teste de Materiais , Microscopia Confocal , Microscopia Eletrônica de Varredura , Cloreto de Potássio/química , Cloreto de Potássio/farmacologia , Pirrolidinonas/química , Reprodutibilidade dos Testes , Irrigantes do Canal Radicular/química , Bicarbonato de Sódio/química , Bicarbonato de Sódio/farmacologia , Cloreto de Sódio/química , Cloreto de Sódio/farmacologia , Estatísticas não Paramétricas
2.
Food Chem ; 317: 126412, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113138

RESUMO

In this study, three whey protein concentrate systems enriched in α-lactalbumin, produced using membrane filtration (LAC-M), selective precipitation (LAC-P) and ion-exchange chromatography (LAC-IE), were fortified with calcium chloride (CaCl2) at 0-5 mM and changes in physicochemical properties studied. Binding of calcium (Ca2+) occurred for LAC-P in the range 0.00-2.00 mM, with an affinity constant (Kd) of 1.63 × 10-7, resulting in a proportion of total protein-bound calcium of 81.8% at 2 mM CaCl2. At 5 mM CaCl2, LAC-P had volume mean diameter (VMD) of 638 nm, while LAC-M and LAC-IE had VMD of 204 and 3.87 nm, respectively. Changes in physicochemical properties were dependent on the approach used to enrich α-lactalbumin and concentrations of other macromolecules (e.g., phospholipid). The results obtained in this study provide fundamental insights into the influence of fortification with soluble calcium salts on the physicochemical stability of next-generation whey protein ingredients enriched in α-lactalbumin.


Assuntos
Cálcio/química , Lactalbumina/química , Proteínas do Soro do Leite/química , Cálcio/metabolismo , Cloreto de Cálcio/química , Cálcio na Dieta , Cromatografia por Troca Iônica , Alimentos Fortificados , Tamanho da Partícula
3.
Food Chem ; 319: 126535, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32187565

RESUMO

The improvement mechanism of high pressure processing (HPP, 100-300 MPa, 10 min) on the gelation properties of reduced-sodium (0.3 M sodium chloride) myofibrillar protein containing 20 mM CaCl2 (MP-Ca) were explored. The results showed that the water holding capacity (WHC) and strength of MP-Ca gel reached the maximum values under 200 MPa. This was attributed to substantial solubilization of myosin heavy chain and actin, a decreased protein aggregation ability and the exposure of both tyrosine and tryptophan residues resulting from the unfolding of the protein tertiary structure. However, 300 MPa induced the hydrophobic rearrangement of MP and the disulfide cross-linking of the myosin S-1 subfragment, leading to the formation of large protein aggregates and decreased solubility of MP, thus resulting in a weaker gel with a reduced WHC. Therefore, moderate HPP (approximately 200 MPa) and low concentrations of CaCl2 could potentially improve the gelation properties of reduced-sodium meat products.


Assuntos
Cloreto de Cálcio/química , Galinhas , Miofibrilas/química , Sódio/química , Actinas/química , Animais , Fenômenos Químicos , Géis/química , Interações Hidrofóbicas e Hidrofílicas , Pressão , Solubilidade , Água/química
4.
Int J Nanomedicine ; 15: 333-346, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32021183

RESUMO

Purpose: Wound healing, especially of extensive full-thickness wounds, is one of the most difficult problems in clinical studies. In this study, we prepared a novel substance P (SP)-delivery system using zeolite imidazolate framework-8 (ZIF-8) nanoparticles. Methods: We synthesized ZIF-8 nanoparticles using a modified biomimetic mineralization method. We then coated SP-loaded ZIF-8 nanoparticles (SP@ZIF-8) with polyethylene glycol-thioketal (PEG-TK) to fabricate SP@ZIF-8-PEG-TK nanoparticles, and encapsulated them in injectable hydrogel composed of sodium alginate and pectin and cross-linked using calcium chloride. The final hydrogel wound dressing containing SP@ZIF-8-PEG-TK nanoparticles was called SP@ZIF-8-PEG-TK@CA. Results: The fabricated ZIF-8 nanoparticles had high SP-loading efficiency. SP-release assay showed that the SP@ZIF-8-PEG-TK nanoparticles maintained drug activity and showed responsive release under stimulation by reactive oxygen species. The SP@ZIF-8-PEG-TK nanoparticles promoted proliferation of human dermal fibroblasts, up-regulated expression levels of inflammation-related genes in macrophages, and exhibited favorable cytocompatibility in vitro. Full-thickness excision wound models in vivo confirmed that SP@ZIF-8-PEG-TK@CA dressings had excellent wound-healing efficacy by promoting an early inflammatory response and subsequent M2 macrophage polarization in the wound-healing process. Conclusion: In conclusion, these findings indicated that SP@ZIF-8-PEG-TK@CA dressings might be useful for wound dressing applications in the clinic.


Assuntos
Bandagens , Nanopartículas/química , Espécies Reativas de Oxigênio/metabolismo , Substância P/administração & dosagem , Cicatrização/efeitos dos fármacos , Zeolitas/química , Alginatos/química , Animais , Cloreto de Cálcio/química , Proliferação de Células/efeitos dos fármacos , Reagentes para Ligações Cruzadas/química , Sistemas de Liberação de Medicamentos/métodos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogéis/química , Imidazóis/química , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Pectinas/química , Polietilenoglicóis/química , Substância P/farmacocinética
5.
J Appl Oral Sci ; 28: e20190105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31800873

RESUMO

Calcium aluminate cement (CAC) has been highlighted as a promising alternative for endodontic use aiming at periapical tissue repair. However, its effects on dental pulp cells have been poorly explored. OBJECTIVE: This study assessed the impact of calcium chloride (CaCl2) and bismuth oxide (Bi2O3) or zinc oxide (ZnO) additives on odontoblast cell response to CAC. METHODOLOGY: MDPC-23 cells were exposed for up to 14 d: 1) CAC with 2.8% CaCl2 and 25% ZnO (CACz); 2) CAC with 2.8% CaCl2 and 25% Bi2O3 (CACb); 3) CAC with 10% CaCl2 and 25% Bi2O3 (CACb+); or 4) mineral trioxide aggregate (MTA), placed on inserts. Non-exposed cultures served as control. Cell morphology, cell viability, gene expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), and dentin matrix protein 1 (DMP-1), ALP activity, and extracellular matrix mineralization were evaluated. Data were compared using ANOVA (α=5%). RESULTS: Lower cell density was detected only for MTA and CACb+ compared with Control, with areas showing reduced cell spreading. Cell viability was similar among groups at days one and three (p>0.05). CACb+ and MTA showed the lowest cell viability values at day seven (p>0.05). CACb and CACb+ promoted higher ALP and BSP expression compared with CACz (p<0.05); despite that, all cements supported ALP activity. Matrix mineralization were enhanced in CACb+ and MTA. CONCLUSION: In conclusion, CAC with Bi2O3, but not with ZnO, supported the expression of odontoblastic phenotype, but only the composition with 10% CaCl2 promoted mineralized matrix formation, rendering it suitable for dentin-pulp complex repair.


Assuntos
Compostos de Alumínio/química , Compostos de Alumínio/farmacologia , Compostos de Cálcio/química , Compostos de Cálcio/farmacologia , Cimentos Dentários/química , Cimentos Dentários/farmacologia , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Fosfatase Alcalina/análise , Fosfatase Alcalina/efeitos dos fármacos , Animais , Bismuto/química , Bismuto/farmacologia , Cloreto de Cálcio/química , Cloreto de Cálcio/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Combinação de Medicamentos , Expressão Gênica/efeitos dos fármacos , Teste de Materiais , Camundongos , Odontoblastos/efeitos dos fármacos , Óxidos/química , Óxidos/farmacologia , Reprodutibilidade dos Testes , Silicatos/química , Silicatos/farmacologia , Fatores de Tempo , Óxido de Zinco/química , Óxido de Zinco/farmacologia
6.
Ecotoxicol Environ Saf ; 189: 109979, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31835044

RESUMO

The sediments of water bodies are not only pollutants sink but also sources of pollution. The assessment for the whole-sediment toxicity is still challenging research. Although the application of immobilized algal bead could overcome the practical difficulties in sediment toxicity assay, the weak growth and reduced sensitivity of algae inside the bead restricted its application. In this study, a sediment toxicity test was developed using immobilized sediment and Chlorella vulgaris. The immobilized sediment was prepared by mixing 2 g freeze-dried sediment and 15-mL 3% (w/v) alginate and hardened in a 4% (w/v) CaCl2 solution. Based on a C. vulgaris growth inhibition test and using the immobilized sediment, the median effective concentration value (EC50) of the spiked Cu and diuron was 506.23 and 2.37 mg/kg respectively, lower than that of using immobilized algae (719.62 and 3.12 mg/kg respectively). The Cu and diuron concentrations in the corresponding overlying water from the spiked immobilized and free sediment showed that sediment pollutants' diffusion capacity was not decreased after immobilization. By using the immobilized sediment in algae toxicity bioassay, the changes in the sediment toxicity of a polluted river before and after dredging was evaluated. The C. vulgaris growth inhibition in sediment A decreased from 81.94% to 8.43%; sediment B remained unchanged; sediment C stimulated the growth of C. vulgaris before dredging (-15.56%), but inhibited the algae growth after dredging (26.88%), and sediment D decreased growth inhibition from 32.66% to -12.60%.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Sedimentos Geológicos/química , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Alginatos/química , Cloreto de Cálcio/química , Chlorella vulgaris/crescimento & desenvolvimento , Cobre/análise , Cobre/toxicidade , Diurona/análise , Diurona/toxicidade , Rios/química , Poluentes Químicos da Água/análise
7.
Carbohydr Polym ; 227: 115340, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590859

RESUMO

The characterization of nanocellulose fibres (NC) length is a difficult and indirect measurement which relies on aspect ratio calculation and fibre diameter analysis. The aspect ratio can be directly calculated from the gel point, a parameter obtained from sedimentation experiments. The gel point has been used with macroscopic fibres and microfibrillated cellulose, that easily sediment by gravity. However, this methodology has not yield consistent results with highly charged nanofibres nor with fibres with sediment layer difficult to observe. In this study, the gel point methodology is modified: 1) dying the fibres with Crystal Violet to enable the visualization of the fibrils sedimentation line without affecting the fibre network; and 2) by optimizing the sedimentation time to ensure complete settling. The two types of fibrils characterized -low and high fibrillated NC (LF-NC, HF-NC)- behave differently due to the slower sedimentation of HF-NC. The time to reach a stable sedimented layer increases with the level of fibre fibrillation, the charge and the decrease of fibre dimension. Reproducible gel point can be measured after 2 days for LF-NC; however, 8 days are required for HF-NC. The modified methodology was validated by quantifying the influence of pH and salt concentration. As expected, low pHs and the addition of CaCl2 coagulate HF-NC into flocs which increase the ratio: final over initial fibres height (Hs/Ho); this decreases significantly the gel point, as a lower amount of HF-NC are required to interconnect all fibres. This modified method is a valuable tool for the accurate dimensional characterisation of highly charged and low diameter cellulose nanofibres.


Assuntos
Celulose/química , Nanoestruturas/química , Cloreto de Cálcio/química , Floculação , Géis , Concentração de Íons de Hidrogênio , Transição de Fase
8.
Food Chem ; 309: 125614, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31678672

RESUMO

Effects of partial substitution of NaCl with KCl, MgCl2 or CaCl2 on oxidative characteristics of myofibrillar protein (MP) in a hydroxyl radical generating system and their heat-induced gel properties were investigated. Results indicated that MP oxidation is dependent upon the different chloride salt types and substitution degree. MP at 0.60 M NaCl was beneficial to protein unfolding and gel quality in the oxidative system. Increased formation of disulfide bonds affected the MP conformation and resulted in a large particle size and an aggregatednetworkofgel at the 50% substitution degree of KCl. The presence of CaCl2 or MgCl2 substitutes contributed to protein polymerization and insolubility. MP aggregation restrained the formation of dense and continuous gel networks during heating, and thus resulted in a low-grade gel. Ca2+ had more serious impact on gel properties than Mg2+, dependent on different cation effects. Substitution of 25% NaCl by KCl gave acceptable gel quality in MP.


Assuntos
Manipulação de Alimentos/métodos , Proteínas Musculares/química , Cloreto de Potássio/química , Cloreto de Sódio/química , Animais , Cloreto de Cálcio/química , Dissulfetos/química , Géis/química , Radical Hidroxila/química , Cloreto de Magnésio/química , Oxirredução , Tamanho da Partícula , Carne de Porco , Desdobramento de Proteína
9.
Food Chem ; 305: 125477, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610424

RESUMO

In recent years there is an increasing interest in dried fruits, although many of their nutritional components are readily lost during drying. The novelty of this paper was to assess the effect of hot-air drying (HAD) and far-infrared drying (FIRD) on the physicochemical properties and microstructure of mango slices pretreated with: control; 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl2 + 1% NaCl; or 0.1% citric acid + 0.5% ascorbic acid + 0.5% CaCl2 + 1% NaCl + ultrasound treatments. Pretreatments resulted in a significant (p < 0.05) increase in reducing sugar, ascorbic acid and total phenol contents of dried samples. Moreover, compared with HAD, FIRD maintained a higher phenolic acid content, improved the nutrient retention and color attributes and better preserved microstructure. Therefore, pretreatments followed by FIRD is a potential method for obtaining high-quality dried mango slices.


Assuntos
Ácido Ascórbico/análise , Dessecação/métodos , Mangifera/química , Fenóis/análise , Ar , Cloreto de Cálcio/química , Cromatografia Líquida de Alta Pressão , Cor , Frutas/química , Frutas/metabolismo , Temperatura Alta , Raios Infravermelhos , Mangifera/metabolismo , Mangifera/ultraestrutura , Espectrometria de Massas , Sonicação
10.
J Mater Sci Mater Med ; 30(10): 114, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31598796

RESUMO

Inspired by the double network hydrogel systems we report the formulation of dual networks, which expands the repertoire of this class of materials for potential biomedical applications. The tough dual network hydrogels were designed through sequential interpenetrating polymer formation, applying green chemistry and low-cost methods, devoid of any initiator-activator complexes that may pose risks in biomedical applications. The dual networks were synthesized in two steps, firstly the water soluble poly(vinyl alcohol) was subjected to cryogelation that formed the first network, which was then expanded by intrusion of a dilute solution of sodium alginate and complexed with a solution of calcium chloride under ambient conditions and further freeze-thawed. These hydrogels are flexible, ductile and porous with the ability to absorb and retain fluids as well as possess the versatility to easily incorporate biological molecules/drugs/antibiotics to be applied in tissue matrices or drug delivery systems. The dual network hydrogels can be tailored to have varying mechanical properties, shapes, size, thickness and particularly can be made physically porous if required, to suit the users intended application.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Osteoblastos/efeitos dos fármacos , Polímeros/química , Alginatos/química , Antibacterianos/química , Cloreto de Cálcio/química , Varredura Diferencial de Calorimetria , Adesão Celular , Sistemas de Liberação de Medicamentos , Matriz Extracelular/metabolismo , Consolidação da Fratura , Química Verde , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Álcool de Polivinil/química , Polivinil/química , Porosidade , Medicina Regenerativa/métodos , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Resistência à Tração , Vancomicina/química , Água/química
11.
ACS Appl Mater Interfaces ; 11(44): 41118-41126, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31612699

RESUMO

The recovery of rare single circulating tumor cells (CTCs) from patients has great potential to facilitate the study of cell heterogeneity and cancer metastasis, which may promote the development of individualized cancer immunotherapy. Herein, a versatile single-cell recovery approach that utilizes an acoustic droplet-induced enzyme responsive platform for the capture and on-demand release of single CTCs is proposed. The platform combines a multifunctional enzyme-responsive gelatin nanoparticle (GNP)-decorated substrate (GNP-chip) for specific capture with an acoustic droplet positioning technique to realize on-demand release of single CTCs. The acoustic droplet dispenser is employed to generate oxidized alginate microdroplets containing the MMP-9 enzyme (OA-MMP-9) with controllable size and precise positioning upon the cell-attached GNP-chip, allowing controlled cell-surface biodegradation under enzymatic reactions followed by calcium chloride (CaCl2) solution treatment to form single-cell encapsulated calcium alginate hydrogels. Benefitting from the existence of hydrogels, the released cells could be efficiently recovered by microcapillary. Results demonstrate that the encapsulated cells maintain good cell morphology in the hydrogels, which allow further single-cell nucleic acid analysis. As a proof-of-concept platform, this approach enables reliable and efficient retrieval of single CTCs and holds the potential for versatility in single-cell analysis systems.


Assuntos
Separação Celular/métodos , Hidrogéis/química , Metaloproteinase 9 da Matriz/metabolismo , Células Neoplásicas Circulantes/química , Alginatos/química , Cloreto de Cálcio/química , Gelatina/química , Humanos , Células MCF-7 , Metaloproteinase 9 da Matriz/química , Microscopia de Fluorescência , Nanopartículas/química , Análise de Célula Única
12.
Nutrients ; 11(10)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618877

RESUMO

Osteoporosis, a systemic skeleton disease, can be prevented by increasing calcium levels in serum via administration of calcium salts. However, traditional calcium-based formulations have not appeared to be effective, hence the purpose of the present work has been to prepare and test in vitro/vivo a formulation able to gradually release calcium during transit over the GI tract, thus increasing bioavailability and reducing daily dose, and hence, side effects. Calcium controlled-release granules based on zeolite and Precirol® were prepared. In the best case, represented by granules sized 1.2 mm, containing 20% Precirol®, 19% zeolite, 60% calcium (granule), the release lasted ≈6 h. The release is controlled by diffusion of calcium ions through the aqueous channels forming within granules, once these come into contact with physiological fluids. Such a diffusion is hindered by the interaction of calcium ions with the negatively charged surface of the zeolite. Ovariectomy was used to make rats osteopenic. For in vivo studies, rats were divided into the following groups. Sham: not treated; ova: ovariectomized (ova); CaCl2 1.0 g: ova, treated with 1.0 g/die Ca2+; CaCl2 0.5 g: ova, treated with 0.5 g/die Ca2+; granule 1.0 g, or granule 0.5 g: ova, treated with granules equivalent to 1.0 g/die or 0.5 g/die Ca2+ in humans. Ca2+ amounts in femur bone and bone marrow, femur mechanical characteristics, and femur medullary canalicule diameter were measured and the same efficacy rank order was obtained: ova < CaCl2 0.5 g < CaCl2 1.0 g < granule 0.5 g ≈ granule 1.0 g ≈ sham. The results show promise of an effective prevention of osteoporosis, based on a controlled-rate administration of a calcium dose half that administered by the current therapy, with reduced side effects.


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Remodelação Óssea/efeitos dos fármacos , Cloreto de Cálcio/administração & dosagem , Diglicerídeos/administração & dosagem , Fêmur/efeitos dos fármacos , Osteoporose Pós-Menopausa/prevenção & controle , Zeolitas/administração & dosagem , Administração Oral , Animais , Biomarcadores/sangue , Conservadores da Densidade Óssea/química , Conservadores da Densidade Óssea/metabolismo , Cloreto de Cálcio/química , Cloreto de Cálcio/metabolismo , Preparações de Ação Retardada , Diglicerídeos/química , Modelos Animais de Doenças , Portadores de Fármacos , Composição de Medicamentos , Liberação Controlada de Fármacos , Fêmur/metabolismo , Fêmur/fisiopatologia , Humanos , Osteocalcina/sangue , Osteoporose Pós-Menopausa/sangue , Osteoporose Pós-Menopausa/etiologia , Osteoporose Pós-Menopausa/fisiopatologia , Ovariectomia , Tamanho da Partícula , Ratos Wistar , Zeolitas/química
13.
Int J Biol Macromol ; 139: 640-646, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31381920

RESUMO

Cellulose nanocrystals (CNCs) is an exciting class of sustainable and carbohydrate material, which has great potential applications in molecular adsorption. However, the complex preparation process and limited adsorption capacity of CNCs hinder its commercial application. In this study, we design a novel functional cellulose nanocrystals-based adsorbent by an ingenious mixing of lignin-containing cellulose nanocrystals (LCNCs), sodium alginate (SA), and calcium chloride solution. Benefiting from the sulfonate groups of lignin, carboxyl groups of SA, the maximum adsorptive capability of LCNCs/SA beads for methylene blue was found to be 1181 mg g-1, which was significantly higher than previously reported biomass-based adsorbents. More importantly, LCNCs/SA beads can be reused several times. This strategy can not only improve the adsorption performance of CNCs-based materials, but also simplify the production technology of CNCs, which greatly promote the commercial application of CNCs materials.


Assuntos
Alginatos/química , Celulose/química , Corantes/química , Lignina/química , Nanopartículas/química , Adsorção , Biomassa , Cloreto de Cálcio/química , Cátions , Hidrogéis/química , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno/química , Compostos Orgânicos/química , Reprodutibilidade dos Testes , Termodinâmica
14.
Macromol Biosci ; 19(9): e1900245, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31386277

RESUMO

The vascular system represents the key supply chain for nutrients and oxygen inside the human body. Engineered solutions to produce sophisticated alternatives for autologous or artificial vascular implants to sustainably replace diseased vascular tissue still remain a key challenge in tissue engineering. In this paper, cell-laden 3D bioplotted hydrogel vessel-like constructs made from alginate di-aldehyde (ADA) and gelatin (GEL) are presented. The aim is to increase the mechanical stability of fibroblast-laden ADA-GEL vessels, tailoring them for maturation under dynamic cell culture conditions. BaCl2 is investigated as a crosslinker for the oxidized alginate-gelatin system. Normal human dermal fibroblast (NHDF)-laden vessel constructs are optimized successfully in terms of higher stiffness by increasing ADA concentration and using BaCl2 , with no toxic effects observed on NHDF. Contrarily, BaCl2 crosslinking of ADA-GEL accelerates cell attachment, viability, and growth from 7d to 24h compared to CaCl2 . Moreover, alignment of cells in the longitudinal direction of the hydrogel vessels when extruding the cell-laden hydrogel crosslinked with Ba2+ is observed. It is possible to tune the stiffness of ADA-GEL by utilizing Ba2+ as crosslinker. In addition, a customized, low-cost 3D printed polycarbonate (PC) perfusion chamber for perfusion of vessel-like constructs is introduced.


Assuntos
Custos e Análise de Custo , Hidrogéis/farmacologia , Perfusão/economia , Impressão Tridimensional/economia , Alginatos/química , Animais , Compostos de Bário/química , Cloreto de Cálcio/química , Polaridade Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cloretos/química , Derme/citologia , Embrião de Mamíferos/citologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/ultraestrutura , Géis , Humanos , Camundongos , Poloxâmero/química , Tecidos Suporte/química
15.
Carbohydr Polym ; 222: 114988, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31320082

RESUMO

This study introduces a novel approach in fabricating bioplatforms with favourable physical, chemical, and mechanical properties for wound dressing applications. The approach employs a three-step method; partial-crosslinking of polymers into soft macromatrices, lyophilization, and pulverization of those macromatrices to obtain polymer particles with improved properties. For investigation of this approach, the ionic polysaccharides, sodium alginate and chitosan were partially crosslinked with calcium chloride and sodium tripolyphosphate, respectively, followed by interpolymer complexation (IPC) for formation of the bioplatform. The formulations displayed good thermal stability with enhanced water uptake. The IPC exhibited water uptake of 4343.4% over 24 h and displayed 78% biodegradation over 14 days, which was superior to that of a commercial alginate-based wound dressing (1612.56% swelling and 16.26% biodegradation). The bioplatform thus possessed promising fluid-absorptivity and biodegradability, for potential application as a wound therapeutic system.


Assuntos
Alginatos/química , Bandagens , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Quitosana/química , Cicatrização , Alginatos/uso terapêutico , Animais , Cloreto de Cálcio/química , Quitosana/uso terapêutico , Camundongos , Células NIH 3T3 , Polifosfatos/química
16.
Chemosphere ; 237: 124417, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31356999

RESUMO

The abuse of antibiotics is becoming increasingly serious, particularly in offshore aquaculture areas. Double-network polymer gel has good prospects for environmental application for the removal of antibiotics. In this work, κ-Carrageenan/Sodium Alginate (κ-car/SA) double-network hydrogels were designed and synthesized with enhanced mechanical properties, anti-swelling, and adsorption capacity. It was found that the intermolecular interaction and viscosity tend to increase with the increasing concentration of κ-carrageenan. The swelling degree of the composite hydrogel in NaCl solution presented a decreasing trend with the increase of carrageenan. SA can effectively improve the mechanical properties of κ-carrageenan composite gel and enhance its compressive resistance and elasticity. Ciprofloxacin (CIP) was used as the model pollutant for testing the adsorption performance. The results show that the Langmuir-Freundlich isotherm model is more suitable for fitting the adsorption isotherm data of CIP on gel beads, which indicates that κ-car/SA hydrogels have heterogeneous surface and different binding sites. κ-car/SA composite double-network hydrogels exhibit excellent adsorption properties for CIP (229 mg/g). The optimal adsorption capacity of κ-car/SA composite hydrogels was obtained at pH 4, and the adsorption capacity of the hydrogels increased with increasing ion concentration. FTIR spectroscopy and the Zeta potential test analyses showed that the adsorption mechanism may be explained by hydrogen bonding and the electrostatic interactions between κ-car/SA composite hydrogels and CIP. The formation of the new double-network hydrogel provided good properties and development potential for the adsorption of antibiotic in water.


Assuntos
Alginatos/química , Carragenina/química , Ciprofloxacino/isolamento & purificação , Hidrogéis/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cloreto de Cálcio/química , Ciprofloxacino/química , Reagentes para Ligações Cruzadas/química , Módulo de Elasticidade , Concentração de Íons de Hidrogênio , Modelos Químicos , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Poluentes Químicos da Água/química
17.
Acta Sci Pol Technol Aliment ; 18(2): 173-184, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31256545

RESUMO

BACKGROUND: Performing iron fortification by adding the iron compound directly into foods helps to tackle the problem of iron deficiency. However, the fortification brings about some problems as well, including undesirable organoleptic effects, oxidation, and reduced bioavailability. Ensuring appropriate encapsulation can overcome these problems. Hence, it is crucial to identify a proper excipient for protecting the iron. Glucomannan has the potential to be a suitable iron encapsulation excipient. The present work therefore sought to prepare an iron excipient from modified glucomannan using the gelation method. Glucomannan modification was conducted by either chemical reaction or in combination with another compound. METHODS: Glucomannan was isolated from Amorphophallus oncophyllus flour. To maximize encapsulation performance, glucomannan was modified by either deacetylation using NaOH (0.4 M) or in combination with alginate. After dissolving the excipient (1%), this solution was mixed with FeSO4 to obtain 25 mg of iron per 1 g of excipient. The mixture was dropped into either an ethanol or CaCl2 solution for gelation. The beads of seven variations of the resultant glucomannan-based excipient were investigated for their encapsulation efficiency, bead size, and swelling. The release of iron in the two pH solutions together with their respective release models were also evaluated. RESULTS: It was revealed that the highest iron efficiency (64%) was achieved using deacetylated glucoman- nan, which was gelled in CaCl2. However, this matrix also resulted in the highest release rate in both pH solutions. The release rate of iron was lower in the low pH solution (pH: 1.2) than in the higher pH solution (pH: 6.8) for all matrix combinations. The Korsmeyer model was the most fitting model for describing the release profile of iron in both pH solutions (R2 ≥ 0.958) for all excipient variations. CONCLUSIONS: This study suggested the potency of modified glucomannan to be pH-sensitive for iron encapsulation.


Assuntos
Amorphophallus/química , Excipientes , Ferro/administração & dosagem , Mananas/química , Alginatos/química , Cloreto de Cálcio/química , Cápsulas , Géis , Humanos , Concentração de Íons de Hidrogênio , Hidróxido de Sódio/química
18.
Luminescence ; 34(7): 739-748, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31304679

RESUMO

ß-Lactoglobulin has been shown to interact with carotenoids from sea buckthorn berries. However, previously, no studies have taken into account the effect of calcium and magnesium on the ß-lactoglobulin-carotenoids complex. This study aims to determine the effect of calcium and magnesium on the interaction between ß-lactoglobulin and carotenoids from sea buckthorn berries extract, during heating from the perspective of deepening interaction mechanisms as prerequisites for micro- and nanoencapsulation. Phase diagram, intrinsic fluorescence spectra, quenching experiments and synchronous spectra were employed to acquire information regarding the conformation of protein in the presence of calcium chloride and magnesium chloride. Intrinsic fluorescence data showed that, between 25°C and 60°C, the presence of calcium chloride in the complex favoured the movement of tryptophan residues to domains located at the protein-water interface, while magnesium chloride favoured the burial of tryptophan residues. Higher temperatures generated blue shifts regardless of which salt was present, suggesting exposure of tryptophan residues to the hydrophobic core of the protein. Extrinsic fluorescence intensity of the non-heat-treated complex with magnesium chloride was significantly higher (P < 0.01) than of the complex with calcium chloride, suggesting that 1-anilino-8-naphtalenesulphonic acid was bound to a higher proportion of the ß-lactoglobulin-carotenoids complex. Calcium chloride increased extrinsic fluorescence to a greater extent than magnesium chloride at temperatures above 70°C and was related to small structural changes induced by preheating ß-lactoglobulin.


Assuntos
Cloreto de Cálcio/química , Hippophae/química , Lactoglobulinas/química , Cloreto de Magnésio/química , Carotenoides/química , Espectrometria de Fluorescência , Temperatura
19.
J Vis Exp ; (147)2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-31157787

RESUMO

Biomineralization is the formation of minerals in the presence of organic molecules, often related with functional and/or structural roles in living organisms. It is a complex process and therefore a simple, in vitro, system is required to understand the effect of isolated molecules on the biomineralization process. In many cases, biomineralization is directed by biopolymers in the extracellular matrix. In order to evaluate the effect of isolated biopolymers on the morphology and structure of calcite in vitro, we have used the vapor diffusion method for the precipitation of calcium carbonate, scanning electron microscopy and micro Raman for the characterization, and ultraviolet-visible (UV/Vis) absorbance for measuring the quantity of a biopolymer in the crystals. In this method, we expose the isolated biopolymers, dissolved in a calcium chloride solution, to gaseous ammonia and carbon dioxide that originate from the decomposition of solid ammonium carbonate. Under the conditions where the solubility product of calcium carbonate is reached, calcium carbonate precipitates and crystals are formed. Calcium carbonate has different polymorphs that differ in their thermodynamic stability: amorphous calcium carbonate, vaterite, aragonite, and calcite. In the absence of biopolymers, under clean conditions, calcium carbonate is mostly present in the calcite form, which is the most thermodynamically stable polymorph of calcium carbonate. This method examines the effect of the biopolymeric additives on the morphology and structure of calcium carbonate crystals. Here, we demonstrate the protocol through the study of an extracellular bacterial protein, TapA, on the formation of calcium carbonate crystals. Specifically, we focus on the experimental set up, and characterization methods, such as optical and electron microscopy as well as Raman spectroscopy.


Assuntos
Biopolímeros/química , Carbonato de Cálcio/química , Minerais/química , Cloreto de Cálcio/química , Microscopia Eletrônica de Varredura , Solubilidade , Análise Espectral Raman , Termodinâmica
20.
Environ Pollut ; 252(Pt B): 1892-1901, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31227348

RESUMO

Soot nanoparticles (SNPs) produced from incomplete combustion have strong impacts on aquatic environments as they eventually reach surface water, where their environmental fate and transport are largely controlled by aggregation. This study investigated the aggregation kinetics of SNPs in the presence of macromolecules including fulvic acid (FA), humic acid (HA), alginate polysaccharide, and bovine serum albumin (BSA, protein) under various environmentally relevant solution conditions. Our results showed that increasing salt concentrations induced SNP aggregation by suppressing electrostatic repulsion and that CaCl2 exhibited stronger effect than NaCl in charge neutralization, which is in agreement with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The aggregation rates of SNPs were variously reduced by macromolecules, and such stabilization effect was the greatest by BSA, followed by HA, alginate, and FA. Steric repulsion resulting from macromolecules adsorbed on SNP surfaces was mainly responsible for enhancing SNP stability. Such steric repulsion appeared to be affected by macromolecular structure, as BSA having a more compact globular structure on SNP surfaces imparted long-range steric repulsive forces and retarded the SNP aggregation rate by 10-100 times. In addition, alginate was shown to enhance SNP aggregation by ∼10 times at high CaCl2 concentrations due to alginate gel formation via calcium bridging. The results may bear strong significance for the fate and transport of SNPs in both natural and controlled environmental systems.


Assuntos
Nanopartículas/química , Fuligem/análise , Fuligem/química , Poluentes Químicos da Água/análise , Poluição da Água/análise , Adsorção , Alginatos/química , Benzopiranos/química , Cloreto de Cálcio/química , Substâncias Húmicas/análise , Soroalbumina Bovina/química , Cloreto de Sódio/química , Água/química
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