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1.
Mater Sci Eng C Mater Biol Appl ; 105: 109912, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546348

RESUMO

In this study, a simple and facile strategy was developed for the synthesis of novel hydroxyapatite (HA)/nanostructured monticellite ceramic composites by mechanical method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS) were used to peruse the phase structure, and morphology of soaked ceramic composites in simulated body fluid (SBF). The in vitro bioactivity of HA-based ceramic composites with nanostructured monticellite ranging from 0 to 50 wt% was evaluated via investigating the formation ability of bone-like calcium phosphates in SBF and the effect of obtained extracts from composites dissolution on osteoblast-like G-292 cell line. Moreover, In vitro cytocompatibility of the HA/monticellite ceramic composites was investigated by MTT, cell growth & adhesion and alkaline phosphatase (ALP) activity assays, and quantitative real-time PCR analysis. The results showed that HA/nanostructured monticellite ceramic composites could induce apatite formation in SBF. The cell proliferation and growth exposed to ceramic composites extracts were significantly stimulated and promoted at a certain concentration range compared to control for various time periods of cell culture. The optimized composite extract enhanced considerably gene expression of G-292 type X collagen (COLX) at different days. Also, G-292 cells were spread and adhered well on the ceramic composite disc. Furthermore, ALP activity of G-292 cells exposed to ceramic composites extracts was dramatically enhanced in comparison with pure HA extract (as control) at different concentrations for various time periods of cell culture. The results suggest that the optimized HA/nanostructured monticellite composite is promising biomaterial for clinical applications such as orthopedic and dentistry.


Assuntos
Materiais Biocompatíveis/síntese química , Tecnologia Biomédica/métodos , Durapatita/síntese química , Nanoestruturas/química , Ácido Silícico/síntese química , Fosfatase Alcalina/metabolismo , Animais , Materiais Biocompatíveis/química , Adesão Celular , Linhagem Celular , Proliferação de Células , Cerâmica/química , Colágeno Tipo X/metabolismo , Corrosão , Durapatita/química , Humanos , Osteoblastos/citologia , Osteogênese , Tamanho da Partícula , Ácido Silícico/química , Difração de Raios X
2.
Mater Sci Eng C Mater Biol Appl ; 103: 109752, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349420

RESUMO

This study focuses on the effect of Sr-, F-, and their co-doping on the structure, biodegradation, bioactivity and cytocompatibility of diopside-based scaffolds, using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, Archimedes densitometry, inductively coupled plasma spectroscopy, pH-metry, and cell MTT assay. The structural characterization of the scaffolds confirmed the successful incorporation of the dopants into the ceramic. In addition, all the doped scaffolds presented higher apatite-forming ability levels in comparison to the undoped one, where the highest and the least impact of doping on bioactivity belonged to F- and co-doping, respectively. It was found that the biodegradation difference of the scaffolds in terms of principal ions and the chance of F-incorporation into precipitated apatite determine the bioactivity difference of the samples. Osteoblast-like MG-63 cells exhibited the highest and lowest compatibility to the Sr-doped and co-doped scaffolds, respectively. In summary, F- and Sr-doping offered the highest bioactivity and cytocompatibility, respectively, whereas co-doping presented the weakest behaviors comparatively.


Assuntos
Flúor/química , Ácido Silícico/química , Ácido Silícico/farmacologia , Estrôncio/química , Tecidos Suporte , Apatitas/química , Neoplasias Ósseas/patologia , Substitutos Ósseos , Linhagem Celular Tumoral , Humanos , Concentração de Íons de Hidrogênio , Teste de Materiais , Microscopia Eletrônica de Varredura , Osteossarcoma/patologia , Análise Espectral Raman , Difração de Raios X
3.
Int J Mol Sci ; 20(12)2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234409

RESUMO

Crystallite aluminosilicates are inorganic microporous materials with well-defined pore-size and pore-structures, and have important industrial applications, including gas adsorption and separation, catalysis, etc. Crystallite aluminosilicates are commonly synthesized via hydrothermal processes, where the oligomerization of silicic acids is crucial. The mechanisms for the oligomerization of poly-silicic acids in neutral aqueous solution were systematically investigated by extensive first-principles-based calculations. We showed that oligomerization of poly-silicic acid molecules proceeds through the lateral attacking and simultaneously proton transfer from the approaching molecule for the formation of a 5-coordinated Si species as the transition state, resulting in the ejection of a water molecule from the formed poly-silicic acid. The barriers for this mechanism are in general more plausible than the conventional direct attacking of poly-silicic acid with reaction barriers in the range of 150-160 kJ/mol. The formation of linear or branched poly-silicic acids by intermolecular oligomerization is only slightly more plausible than the formation of cyclic poly-silicic acids via intramolecular oligomerization according to the reaction barriers (124.2-133.0 vs. 130.6-144.9 kJ/mol). The potential contributions of oligomer structures, such as the length of the linear oligomers, ring distortions and neighboring linear branches, etc., to the oligomerization were also investigated but found negligible. According to the small differences among the reaction barriers, we proposed that kinetic selectivity of the poly-silicic acids condensation would be weak in neutral aqueous solution and the formation of zeolite-like structures would be thermodynamics driven.


Assuntos
Ácido Silícico/química , Água/química , Zeolitas/química , Silicatos de Alumínio/química , Dimerização , Cinética , Modelos Moleculares , Soluções , Termodinâmica
4.
Mater Sci Eng C Mater Biol Appl ; 98: 1087-1096, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30812992

RESUMO

In this research, novel monticellite/hydroxyapatite (HA) ceramic composites were successfully prepared by mechanical method. The ability of nanostructured monticellite-based ceramic composites to form a suitable bond to living hard tissues, and stimulate osteoblast-like cells proliferation may be different for various ratios of the reinforcement to monticellite matrix. The differences in physico-chemical characteristics, bone-like apatite formation, cytocompatibility, cell viability and in vitro osteogenic activity of nanostructured monticellite/HA ceramic composites were explored. The surface reactivity and bioactivity of the composite samples were evaluated in vitro in simulated body fluid (SBF). A comparative time- and dose-dependent MTT test showed that the ions release from nanostructured monticellite/HA composites dissolution significantly stimulated cell proliferation and growth than control at a certain concentration range. The cells viability exposed to the composite extract was higher than control and mineral material of bone (HA), illustrating that cytocompatibility was improved due to the presence of magnesium (Mg) and silicon (Si) elements in the composite structure. The comparative results of alkaline phosphatase (ALP) bioactivity assay showed that the osteogenic proliferation of osteoblast-like G292 cell was increased more by the ceramic composites extract than control. These comparative results demonstrated that nanostructured monticellite-based ceramic composites possessed good in vitro bioactivity, cytocompatibility and osteogenic properties, and may be utilized as the promising bioactive materials for bone tissue regeneration and replacement.


Assuntos
Materiais Biocompatíveis/química , Durapatita/química , Nanoestruturas/química , Ácido Silícico/química , Materiais Biocompatíveis/farmacologia , Líquidos Corporais/química , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/química , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Cerâmica/química , Humanos , Teste de Materiais/métodos , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos
5.
Int J Biol Macromol ; 124: 429-443, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30452982

RESUMO

A novel adsorbent of chitosan/nanodiopside nanocomposite (CS-NDIO) was synthesized as a green composite for the removal of crystal violet (CV) and characterized by techniques like XRD, FT-IR, BET, and FESEM analysis. The influence of parameters like molar ratios of CS to NDIO, initial pH of the solution, dosage of adsorbent, initial concentration of CV and contact time was investigated and evaluated by central composite design (CCD; 5 levels and 4 factors). Also, Hybrid model of (ANN) model with genetic algorithm (GA) optimization was applied to the experimental data get through CCD. The optimized molar ratio of CS-NDIO was found: 20/80. Optimal parameter choice for maximum CV adsorption process using CCD and ANN-GA were as follows: pH = 7.50 and 7.499, adsorbent mass: 0.0077 and 0.0077 g, CV concentration: 20.000 and 20.002 mg/L, and contact time: 25.00 and 25.00 min, respectively. The evaluation adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model (qmax: 104.66 mg g-1 and R2: 0.9937) and pseudo-second order kinetics mechanism (R2: 0.9978). Thermodynamic parameters (R2: 0.9180, ΔH°: -74.93 kJ mol-1, ΔG°: -12.89 kJ mol-1, and ΔS°: 0.93 kJ mol-1 K-1) were calculated and indicating adsorption to be an exothermic and spontaneous process.


Assuntos
Quitosana/química , Violeta Genciana/isolamento & purificação , Nanocompostos/química , Ácido Silícico/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Análise Fatorial , Humanos , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/ultraestrutura , Temperatura , Termodinâmica , Águas Residuárias/química
6.
Biol Lett ; 14(10)2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30282746

RESUMO

The cell wall polymer callose catalyses the formation of silica in vitro and is heavily implicated in biological silicification in Equisetum (horsetail) and Arabidopsis (thale cress) in vivo Callose, a ß-1,3-glucan, is an ideal partner for silicification, because its amorphous structure and ephemeral nature provide suitable microenvironments to support the condensation of silicic acid into silica. Herein, using scanning electron microscopy, immunohistochemistry and fluorescence, we provide further evidence of the cooperative nature of callose and silica in biological silicification in rice, an important crop plant and known silica accumulator. These new data along with recently published research enable us to propose a model to describe the intracellular events that together determine callose-driven biological silicification.


Assuntos
Glucanos , Oryza/metabolismo , Dióxido de Silício/metabolismo , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Imagem Óptica , Oryza/química , Ácido Silícico/química , Dióxido de Silício/química
7.
Colloids Surf B Biointerfaces ; 161: 620-627, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29156339

RESUMO

The silicon transport and use inside cells are key processes for understanding how diatoms metabolize this element in the silica biogenic cycle in the ocean. A spin-probe electron paramagnetic resonance (EPR) study over time helped to investigate the interacting properties and the internalization mechanisms of silicic acid from different silicon sources into the cells. Diatom cells were grown in media containing biogenic amorphous substrates, such as diatomaceous earth and sponge spicules, and crystalline sodium metasilicate. It was found that the amorphous biogenic silicon slowed down the internalization process probably due to formation of colloidal particles at the cell surface after silicic acid condensation. Weaker interactions occurred with sponge spicules silicon source if compared to the other sources. The EPR results were explained by analyzing transcript level changes of silicon transporters (SITs) and silaffins (SILs) in synchronized Thalassiosira pseudonana cultures over time. The results indicated that the transport role of SITs is minor for silicic acid from both biogenic and crystalline substrates, and the role of SIT3 is linked to the transport of silicon inside the cells, mainly in the presence of sponge spicules. SIL3 transcripts were expressed in the presence of all silicon sources, while SIL1 transcripts only with sponge spicules. The data suggest that the transport of silicic acid from various silicon sources in diatoms is based on different physico-chemical interactions with the cell surface.


Assuntos
Coloides/química , Diatomáceas/química , Ácido Silícico/química , Dióxido de Silício/química , Silício/química , Proteínas de Algas/genética , Proteínas de Algas/metabolismo , Coloides/metabolismo , Diatomáceas/genética , Diatomáceas/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Expressão Gênica , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Ácido Silícico/metabolismo , Silício/metabolismo , Dióxido de Silício/metabolismo , Propriedades de Superfície
8.
Drug Dev Ind Pharm ; 44(1): 30-39, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28836872

RESUMO

OBJECTIVE: Research to measure the chemical characterization of alginate rafts for good raft performance and ascertain how formulation can affect chemical parameters. SIGNIFICANCE: A selection of alginate formulations was investigated all claiming to be proficient raft formers with significance between products established and ranked. METHODS: Procedures were selected which demonstrated the chemical characterization allowing rafts to effectively impede the reflux into the esophagus or in severe cases to be refluxed preferentially into the esophagus and exert a demulcent effect, with focus of current research on methods which complement previous studies centered on physical properties. The alginate content was analyzed by a newly developed HPLC method. Methods were used to determine the neutralization profile and the acid neutralization within the raft determined along with how raft structure affects neutralization. RESULTS: Alginate content of Gaviscon Double Action (GDA) within the raft was significantly superior (p < .0001) to all competitor products. The two products with the highest raft acid neutralization capacity were GDA and Rennie Duo, the latter product not being a raft former. Raft structure was key and GDA had the right level of porosity to allow for longer duration of neutralization. CONCLUSION: Alginate formulations require three chemical reactions to take place simultaneously: transformation to alginic acid, sodium carbonate reacting to form carbon dioxide, calcium releasing free calcium ions to bind with alginic acid providing strength to raft formation. GDA was significantly superior (p <.0001) to all other comparators.


Assuntos
Alginatos/química , Hidróxido de Alumínio/química , Antiácidos/química , Carbonato de Cálcio/química , Carbonatos/química , Esôfago/química , Refluxo Gastroesofágico/tratamento farmacológico , Magnésio/química , Ácido Silícico/química , Bicarbonato de Sódio/química , Alginatos/farmacologia , Alginatos/uso terapêutico , Antiácidos/metabolismo , Antiácidos/uso terapêutico , Combinação de Medicamentos , Impedância Elétrica , Refluxo Gastroesofágico/metabolismo , Ácido Glucurônico/química , Ácido Glucurônico/farmacologia , Ácido Glucurônico/uso terapêutico , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacologia , Ácidos Hexurônicos/uso terapêutico , Humanos
9.
J Mech Behav Biomed Mater ; 77: 534-538, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29054090

RESUMO

In the present work, the releasing heat, scaffold apatite formation, and magnetic behavior of a novel diopside-magnetite nanocomposite with various contents of magnetite (Fe3O4) were evaluated. The N´eel and Brown relaxations did not have a significant effect on the specific absorption rate (SAR) of the composite samples. Indeed, magnetic saturation, Ms, indicated a crucial effect on the heat release of the samples. The sample with 30wt% magnetite had the highest value of SAR, while the sample with 20wt% magnetite, in the form of scaffold, allowed the high amount of apatite formation on its surface.


Assuntos
Óxido Ferroso-Férrico/química , Temperatura Alta , Nanopartículas/química , Ácido Silícico/química , Calorimetria , Cerâmica , Força Compressiva , Magnetismo , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos , Porosidade , Pós , Pressão , Difração de Raios X
10.
Proteins ; 85(11): 2111-2126, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28799215

RESUMO

The silica forming repeat R5 of sil1 from Cylindrotheca fusiformis was the blueprint for the design of P5 S3 , a 50-residue peptide which can be produced in large amounts by recombinant bacterial expression. It contains 5 protein kinase A target sites and is highly cationic due to 10 lysine and 10 arginine residues. In the presence of supersaturated orthosilicic acid P5 S3 enhances silica-formation whereas it retards the dissolution of amorphous silica (SiO2 ) at globally undersaturated concentrations. The secondary structure of P5 S3 during these 2 processes was studied by circular dichroism (CD) spectroscopy, complemented by nuclear magnetic resonance (NMR) spectroscopy of the peptide in the absence of silicate. The NMR studies of dual-labeled (13 C, 15 N) P5 S3 revealed a disordered structure at pH 2.8 and 4.5. Within the pH range of 4.5-9.5 in the absence of silicic acid, the CD data showed a disordered structure with the suggestion of some polyproline II character. Upon silicic acid polymerization and during dissolution of preformed silica, the CD spectrum of P5 S3 indicated partial transition into an α-helical conformation which was transient during silica-dissolution. The secondary structural changes observed for P5 S3 correlate with the presence of oligomeric/polymeric silicic acid, presumably due to P5 S3 -silica interactions. These P5 S3 -silica interactions appear, at least in part, ionic in nature since negatively charged dodecylsulfate caused similar perturbations to the P5 S3 CD spectrum as observed with silica, while uncharged ß-d-dodecyl maltoside did not affect the CD spectrum of P5 S3 . Thus, with an associated increase in α-helical character, P5 S3 influences both the condensation of silicic acid into silica and its decondensation back to silicic acid.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Peptídeos/química , Ácido Silícico/química , Dióxido de Silício/química , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos/metabolismo , Conformação Proteica , Ácido Silícico/metabolismo , Dióxido de Silício/metabolismo , Cloreto de Sódio
11.
Sci Rep ; 7(1): 4743, 2017 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-28684783

RESUMO

Easy-to-prepare drug delivery systems, based on smart, silica gels have been synthesized, characterized, and studied as hosts in the controlled release of bisphosphonates. They exhibit variable release rates and final % release, depending on the nature of bisphosphonate (side-chain length, hydro-philicity/-phobicity, water-solubility), cations present, pH and temperature. These gels are robust, injectable, re-loadable and re-usable.


Assuntos
Conservadores da Densidade Óssea/química , Preparações de Ação Retardada/química , Difosfonatos/química , Hidrogéis/química , Conservadores da Densidade Óssea/síntese química , Difosfonatos/síntese química , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Injeções , Cinética , Osteoporose/tratamento farmacológico , Silicatos/química , Ácido Silícico/química , Solubilidade , Soluções , Temperatura
12.
Colloids Surf B Biointerfaces ; 155: 530-537, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28494431

RESUMO

There is good evidence that certain silicon-containing materials promote would healing and their common feature is the delivery of orthosilicic acid (Si(OH)4) either directly or following metabolism. In this respect, amorphous silica nanoparticles (NP), which dissolve in aqueous environments releasing up to 2mM orthosilicic acid, may be appropriate 'slow release' vehicles for bioactive silicon. Here we studied the impact of silica NP suspensions (primary particles∼10nm) in undersaturated conditions (below 2mM Si) with differing degrees of surface charge and dissolution rate on human dermal fibroblasts (CCD-25SK cells) viability, proliferation and migration in a cellular wound model. Silica was shown to be non-toxic for all forms and concentrations tested and whilst the anticipated stimulatory effect of orthosilicic acid was observed, the silica NPs also stimulated fibroblast proliferation and migration. In particular, the amine-functionalized particles promoted wound closure more rapidly than soluble orthosilicic acid alone. We suggest that this effect is related to easy cellular internalization of these particles followed by their intracellular dissolution releasing silicic acid at a faster rate than its direct uptake from the medium. Our findings indicate that amorphous silica-based NPs may favour the delivery and release of bioactive silicic acid to cells, promoting wound healing.


Assuntos
Nanopartículas/química , Ácido Silícico/farmacologia , Dióxido de Silício/química , Cicatrização/efeitos dos fármacos , Aminas/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Fibroblastos/efeitos dos fármacos , Humanos , Ácido Silícico/química , Dióxido de Silício/farmacologia
14.
Molecules ; 22(4)2017 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-28333113

RESUMO

Diopside (DIOP) was introduced into polyetheretherketone/polyglycolicacid (PEEK/PGA) scaffolds fabricated via selective laser sintering to improve bioactivity. The DIOP surface was then modified using a silane coupling agent, 3-glycidoxypropyltrimethoxysilane (KH570), to reinforce interfacial adhesion. The results showed that the tensile properties and thermal stability of the scaffolds were significantly enhanced. It could be explained that, on the one hand, the hydrophilic group of KH570 formed an organic covalent bond with the hydroxy group on DIOP surface. On the other hand, there existed relatively high compatibility between its hydrophobic group and the biopolymer matrix. Thus, the ameliorated interface interaction led to a homogeneous state of DIOP dispersion in the matrix. More importantly, an in vitro bioactivity study demonstrated that the scaffolds with KH570-modified DIOP (KDIOP) exhibited the capability of forming a layer of apatite. In addition, cell culture experiments revealed that they had good biocompatibility compared to the scaffolds without KDIOP. It indicated that the scaffolds with KDIOP possess potential application in tissue engineering.


Assuntos
Silanos/síntese química , Ácido Silícico/química , Linhagem Celular , Humanos , Silanos/química , Propriedades de Superfície
15.
Mater Sci Eng C Mater Biol Appl ; 72: 259-267, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28024584

RESUMO

In the present study three akermanite (Ca2MgSi2O7), diopside (CaMgSi2O6) and baghdadite (Ca3ZrSi2O9) applicable bioceramics were synthesized via a sol-gel based method. The combination of sol-gel method and the raw materials used in this study presents a new route for the synthesis of the mentioned bioceramics. By the use of thermal analysis, the mechanisms occurred during the synthesis of these bioceramics were investigated. The differences in the structural density and their relation with the degradation rate and mechanical properties of all three ceramics were studied. In vitro bioactivity and apatite formation mechanisms of the samples soaked in the simulated body fluid were considered. The results showed that baghdadite as a Zr-containing material has a more dense structure in comparison with the other ceramics, which leads to a lower degradation rate and also lower bioactivity. There were also main differences between akermanite and diopside as Mg-containing ceramics. Diopside showed a structure with lower porosity content compared to the akermanite samples which resulted in the lower degradation rate and higher compressive strength.


Assuntos
Materiais Biocompatíveis/química , Cerâmica/química , Silicatos/química , Ácido Silícico/química , Materiais Biocompatíveis/síntese química , Géis/química , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
J Biomater Sci Polym Ed ; 28(1): 1-14, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27604099

RESUMO

ß-chitin/nanodiopside/nanohydroxyapatite (CT/nDP/nHAp) composite scaffolds were synthesized from the combination of chitin, nDP, and nHAp in different inorganic/organic weight ratios by the freeze-drying technique. The prepared nHAp, and composite scaffolds were characterized by BET, TG, FT-IR, SEM, and XRD studies. The composite scaffolds had 50-75% porosities with well-defined interconnected porous networks. Moreover, investigation of the cell attachment and viability using MTT, DMEM solution, and mouse preosteoblast cell proved the cytocompatibile nature of the composite scaffolds with improved cell adhesion. All these results mainly illustrated that this composite could be a candidate for bone tissue engineering application.


Assuntos
Materiais Biocompatíveis/química , Quitina/química , Durapatita/química , Ácido Silícico/química , Engenharia Tecidual , Tecidos Suporte/química , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Teste de Materiais , Fenômenos Mecânicos
17.
J Appl Biomater Funct Mater ; 15(1): e101-e106, 2017 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-27647387

RESUMO

BACKGROUND: The aim of this study was to investigate the effectiveness of different remineralization agents by quantitative light-induced fluorescence digital BiluminatorTM (QLF-D). METHODS: Artificial caries lesions were created, and the teeth were divided according to the tested materials: (i) distilled water, (ii) acidulated phosphate fluoride (APF), (iii) Curodont Repair (CR), (iv) ammonium hexafluorosilicate (SiF) and (v) ammonium hexafluorosilicate plus cetylpyridinium chloride (SiF + CPC). After treatment procedures, each of the samples was placed in artificial saliva. After demineralization and 1 and 4 weeks of remineralization procedures, fluorescence loss and lesion areas were measured with QLF-D. Data were statistically analyzed (α = 0.05). RESULTS:: The fluorescence values of the demineralized enamel specimens treated with the various agents differed significantly compared with pretreatment values for both 1 and 4 weeks (p<0.05). At 4 weeks, the highest fluorescence gain was calculated in the CR, APF and SiF groups compared with the control (p<0.05). CONCLUSIONS:: APF, SiF and CR groups yielded greater remineralization ability than SiF + CPC and control groups.


Assuntos
Fluoreto de Fosfato Acidulado/química , Cetilpiridínio/química , Fluorescência , Fluoretos/química , Ácido Silícico/química
18.
Biomaterials ; 113: 203-216, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27821306

RESUMO

The immunomodulatory functions of monocytes are increasingly being recognized. Silicified collagen scaffolds (SCSs), produced by infiltrating collagen matrices with intrafibrillar amorphous silica, exhibit osteogenic and angiogenic potential and are promising candidates in tissue engineering. Here, we demonstrate that SCS promotes in situ bone regeneration and angiogenesis via monocyte immunomodulation. Increased numbers of TRAP-positive monocytes, nestin-positive bone marrow stromal cells (BMSCs) and CD31-positive and endomucin-positive new vessels can be identified from new bone formation regions in a murine calvarial defect model. In addition, sustained release of silicic acid by SCS stimulates differentiation of blood-derived monocytes into TRAP-positive cells, with increased expressions of SDF-1α, TGF-ß1, VEGFa and PDGF-BB. These cytokines further promote homing of BMSCs and endothelial progenitor cells as well as neovascularization. Taken together, these novel findings indicate that SCSs possess the ability to enhance recruitment of progenitor cells and promote osteogenesis and angiogenesis by immunomodulation of monocytes.


Assuntos
Regeneração Óssea , Colágeno/química , Monócitos/citologia , Neovascularização Fisiológica , Ácido Silícico/química , Crânio/fisiologia , Tecidos Suporte/química , Animais , Células Cultivadas , Quimiotaxia , Colágeno/imunologia , Imunomodulação , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/imunologia , Camundongos Endogâmicos C57BL , Monócitos/imunologia , Ácido Silícico/imunologia , Crânio/irrigação sanguínea , Crânio/imunologia , Crânio/lesões
19.
Quintessence Int ; 48(2): 123-130, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27981268

RESUMO

OBJECTIVE: The daily removal of supragingival dental plaque is a key factor in the prevention of gingivitis. The aim of the study was to compare the gingival health benefits of a triclosan/copolymer/fluoride toothpaste (Colgate Total, a fluoride toothpaste containing an antiseptic) to a commercially available toothpaste containing 0.243% sodium fluoride in a silica base (Colgate Herbal, a conventional fluoride toothpaste with herbal extracts). METHOD AND MATERIALS: A total of 50 patients with gingivitis and at least one sensitive tooth were included. The subjects were randomly stratified into two groups: Colgate Total toothpaste, and Colgate Herbal toothpaste. After a 4-week pre-experimental phase, baseline Plaque Index (Quigley-Hein Index) (PI), Gingival Index (GI), Gingival Bleeding Index (GBI), and Visual Analog Scale (VAS) were assessed. The PI, GI, GBI, and VAS were reexamined at weeks 4, 12, and 24 after the baseline. RESULTS: Fifty subjects complied with the protocol and completed the study. The conventional fluoride toothpaste with herbal extracts group and the fluoride toothpaste containing an antiseptic group exhibited significant reductions in PI, GI, GBI, and VAS over time. The amount of reduction after 6 months of the treatment was higher in the Total group compared to Herbal group (1.82 vs 1.39, P = .015 for PI; 0.67 vs 0.37, P < .005 for GI; and 56.64% vs 34.26%, P < .005 for GBI). No significant difference was seen for VAS. CONCLUSION: Twice daily brushing with a toothpaste containing 0.3% triclosan and polyvinyl methyl ether and maleic acid copolymer provides a more effective level of plaque control and gingival health with no effect on decreasing dentin hypersensitivity compared to conventional fluoride toothpaste. Toothpastes containing triclosan/copolymer, in addition to fluoride, result in a higher reduction in plaque, gingival inflammation, and gingival bleeding when compared with fluoride toothpastes without triclosan/copolymer.


Assuntos
Placa Dentária/tratamento farmacológico , Dentifrícios/uso terapêutico , Sensibilidade da Dentina/tratamento farmacológico , Gengivite/tratamento farmacológico , Cremes Dentais/uso terapêutico , Adulto , Índice de Placa Dentária , Dentifrícios/química , Feminino , Humanos , Masculino , Índice Periodontal , Ácido Silícico/química , Ácido Silícico/uso terapêutico , Método Simples-Cego , Cremes Dentais/química , Resultado do Tratamento
20.
Acta Biomater ; 50: 56-67, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28017870

RESUMO

Magnesium is a trace element in the human body, known to have important effects on cell differentiation and the mineralisation of calcified tissues. This study aimed to synthesise highly porous Ca-Mg silicate foamed scaffolds from preceramic polymers, with analysis of their biological response. Akermanite (Ak) and wollastonite-diopside (WD) ceramic foams were obtained from the pyrolysis of a liquid silicone mixed with reactive fillers. The porous structure was obtained by controlled water release from selected fillers (magnesium hydroxide and borax) at 350°C. The homogeneous distribution of open pores, with interconnects of modal diameters of 160-180µm was obtained and maintained after firing at 1100°C. Foams, with porosity exceeding 80%, exhibited compressive strength values of 1-2MPa. In vitro studies were conducted by immersion in SBF for 21days, showing suitable dissolution rates, pH and ionic concentrations. Cytotoxicity analysis performed in accordance with ISO10993-5 and ISO10993-12 standards confirmed excellent biocompatibility of both Ak and WD foams. In addition, MC3T3-E1 cells cultured on the Mg-containing scaffolds demonstrated enhanced osteogenic differentiation and the expression of osteogenic markers including Collagen Type I, Osteopontin and Osteocalcin, in comparison to Mg-free counterparts. The results suggest that the addition of magnesium can further enhance the bioactivity and the potential for bone regeneration applications of Ca-silicate materials. STATEMENTS OF SIGNIFICANCE: Here, we show that the incorporation of Mg in Ca-silicates plays a significant role in the enhancement of the osteogenic differentiation and matrix formation of MC3T3-E1 cells, cultured on polymer-derived highly porous scaffolds. Reduced degradation rates and improved mechanical properties are also observed, compared to Mg-free counterparts, suggesting the great potential of Ca-Mg silicates as bone tissue engineering materials. Excellent biocompatibility of the new materials, in accordance to the ISO10993-5 and ISO10993-12 standard guidelines, confirms the preceramic polymer route as an efficient synthesis methodology for bone scaffolds. The use of hydrated fillers as porogens is an additional novelty feature presented in the manuscript.


Assuntos
Compostos de Cálcio , Cerâmica , Silicatos de Magnésio , Teste de Materiais , Silicatos , Animais , Antígenos de Diferenciação/biossíntese , Compostos de Cálcio/química , Compostos de Cálcio/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cerâmica/síntese química , Cerâmica/química , Cerâmica/farmacologia , Força Compressiva , Silicatos de Magnésio/química , Silicatos de Magnésio/farmacologia , Camundongos , Porosidade , Silicatos/química , Silicatos/farmacologia , Ácido Silícico/química , Ácido Silícico/farmacologia
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