RESUMEN
It is of great significance to disclose the diverse aging pathways for polymers under multiple factors, so as to predict and control the potential aging evolution. However, the current methods fail to distinguish multiple pathways (multi-paths) of polymer aging due to the lack of spatiotemporal resolution. In this work, using polyimide as a model polymer, the hydroxyl, carboxyl, and amino groups from the polyimide aging process were labeled using specific fluorescent probes through boron-oxygen, imine, and thiourea linkages, respectively. When the excitation and emission wavelengths of each fluorescent probe were controlled, the multi-paths in polyimide aging can be visualized individually and simultaneously in three-dimensional fluorescent images. The overall aging process under hydrothermal treatment was destructured into the pyrolysis and hydrolysis pathways. Three-dimensional dynamic studies discovered that the increased humidity, along with the decreased oxygen content, could hamper the pyrolysis reaction and accelerate the hydrolysis reaction, leading to severe degradation of the overall polyimide aging. More importantly, the oxygen showed a higher regulation coefficient in accelerating the pyrolysis reaction, than the water vapor in motivating the hydrolysis reactions. Such a multidimensional identification methodology is able to guide the long-term use of polymers and control their aging process to a harmless direction in advance by tuning the contents of oxygen and water vapor.
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Colorantes Fluorescentes , Polímeros , Hidrólisis , Oxígeno , PirólisisRESUMEN
Transparent and flexible gas-barrier materials have shown broad applications in electronics, food, and pharmaceutical preservation. Herein, we report ultrahigh-gas-barrier films with a brick-mortar-sand structure fabricated by layer-by-layer (LBL) assembly of XAl-layered double hydroxide (LDH, X=Mg, Ni, Zn, Co) nanoplatelets and polyacrylic acid (PAA) followed by CO2 infilling, denoted as (XAl-LDH/PAA)n-CO2. The near-perfectly parallel orientation of the LDH "brick" creates a long diffusion length to hinder the transmission of gas molecules in the PAA "mortar". Most significantly, both the experimental studies and theoretical simulations reveal that the chemically adsorbed CO2 acts like "sand" to fill the free volume at the organic-inorganic interface, which further depresses the diffusion of permeating gas. The strategy presented here provides a new insight into the perception of barrier mechanism, and the (XAl-LDH/PAA)n-CO2 film is among the best gas barrier films ever reported.
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Resinas Acrílicas/química , Dióxido de Carbono/química , Gases/química , Hidróxidos/química , Nanoestructuras/química , Adsorción , Cobalto/química , Difusión , Magnesio/química , Modelos Moleculares , Nanoestructuras/ultraestructura , Níquel/química , Zinc/químicaRESUMEN
A CoAl-layered double hydroxide (LDH)@poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanoplatelet array (NPA) is grown on a flexible Ni foil substrate as a high-performance pseudocapacitor. The LDH@PEDOT core/shell NPA shows a maximum specific capacitance of 649 F/g (based on the total mass) by cyclic voltammetry (scan rate: 2 mV/s) and 672 F/g by galvanostatic discharge (current density: 1 A/g). Furthermore, the hybrid NPA electrode also exhibits excellent rate capability with a specific energy of 39.4 Wh/kg at a current density of 40 A/g, as well as good long-term cycling stability (92.5% of its original capacitance is retained after 5000 cycles). These performances are superior to those of conventional supercapacitors and LDH NPA without the PEDOT coating. The largely enhanced pseudocapacitor behavior of the LDH@PEDOT NPA electrode is related to the synergistic effect of its individual components: the LDH nanoplatelet core provides abundant energy-storage capacity, while the highly conductive PEDOT shell and porous architecture facilitate the electron/mass transport in the redox reaction.
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Compuestos Bicíclicos Heterocíclicos con Puentes/química , Nanopartículas/química , Nanotecnología/métodos , Polímeros/química , Aluminio/química , Cobalto/química , Análisis Costo-Beneficio , Difusión , Electroquímica/métodos , Electrodos , Electrones , Hidróxidos/química , Microscopía Electrónica de Rastreo/métodos , Modelos Químicos , Modelos Estadísticos , Níquel/química , Oxidación-Reducción , Óxidos/químicaRESUMEN
A fluorescent logic gate was fabricated based on calcein/layered double hydroxide ultrathin films (UTFs) via alternate assembly technique, which exhibits high stability, reversibility, and resettability. The logic gate was manipulated by utilizing pH value, Hg(2+) and Cl(-) ion as inputs, and the fluorescence emission of the (calcein/LDH)(16) UTF as output, serving as a three-input logic gate that combines the YES and INHIBIT operation.
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Fluoresceínas/química , Fluorescencia , Hidróxidos/química , Membranas Artificiales , Concentración de Iones de Hidrógeno , Lógica , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
In this paper we report the fabrication of layered double hydroxide (LDH) nanoparticles/poly(N-isopropylacrylamide) (pNIPAM) ultrathin films (UTFs) via the layer-by-layer assembly technique, and their switchable electrocatalytic performance in response to temperature stimuli was demonstrated. X-ray diffraction and UV-vis absorption spectroscopy indicate a periodic layered structure with uniform and regular growth of the (LDH/pNIPAM)(n) UTFs; an interaction based on hydrogen bonding between LDH nanoparticles and pNIPAM was confirmed by X-ray-photoelectron spectroscopy and Fourier transform infrared spectroscopy. Temperature-triggered cyclic voltammetry and electrochemical impedance spectroscopy switch for the UTFs was obtained between 20 and 40 °C, accompanied by reversible changes in surface topography and film thickness revealed by atomic force microscopy and ellipsometry, respectively. The electrochemical on-off property of the temperature-controlled (LDH/pNIPAM)(n) UTFs originates from the contraction-expansion configuration of pNIPAM with low-high electrochemical impedance. In addition, a switchable electrocatalytic behavior of the (LDH/pNIPAM)(n) UTFs toward the oxidation of glucose was observed, resulting from the temperature-controlled charge transfer rate. Therefore, this work provides a facile approach for the design and fabrication of a well-ordered command interface with a temperature-sensitive property, which can be potentially applied in electrochemical sensors and switching.
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Acrilamidas/química , Electroquímica/métodos , Hidróxidos/química , Polímeros/química , Temperatura , Resinas Acrílicas , Catálisis , Electrodos , Enlace de Hidrógeno , Modelos Moleculares , Conformación Molecular , Compuestos de Estaño/químicaRESUMEN
The ordered ultrathin films (UTFs) based on CoFe-LDH (layered double hydroxide) nanoplatelets and manganese porphyrin (Mn-TPPS) have been fabricated on ITO substrates via a magnetic-field-assisted (MFA) layer-by-layer (LBL) method and were demonstrated as an electrochemical sensor for glucose. The XRD pattern for the film indicates a long-range stacking order in the normal direction of the substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of the MFA LDH/Mn-TPPS UTFs reveal a continuous and uniform surface morphology. Cyclic voltammetry, impedance spectroscopy, and chronoamperometry were used to evaluate the electrochemical performance of the film, and the results show that the MFA-0.5 (0.5 T magnetic field) CoFe-LDH/Mn-TPPS-modified electrode displays the strongest redox current peaks and fastest electron transfer process compared with those of MFA-0 (without magnetic-field) and MFA-0.15 (0.15 T magnetic field). Furthermore, the MFA-0.5 CoFe-LDH/Mn-TPPS exhibits remarkable electrocatalytic activity toward the oxidation of glucose with a linear response range (0.1-15 mM; R(2) = 0.999), low detection limit (0.79 µM) and high sensitivity (66.3 µA mM(-1) cm(-2)). In addition, the glucose sensor prepared by the MFA LBL method also shows good selectivity and reproducibility as well as resistance to poisoning in a chloride ion solution. Therefore, the novel strategy in this work creates new opportunities for the fabrication of nonenzyme sensors with prospective applications in practical detection.
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Glucosa/análisis , Hidróxidos/química , Magnetismo , Membranas Artificiales , Metaloporfirinas/química , Electrodos , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
The sulfonated phenylenevinylene polyanion derivate (APPV) and exfoliated Mg-Al-layered double hydroxide (LDH) monolayers were alternatively assembled into ordered ultrathin films (UTFs) employing a layer-by-layer method, which shows uniform yellow luminescence. UV-vis absorption and fluorescence spectroscopy present a stepwise and regular growth of the UTFs upon increasing deposited cycles. X-ray diffraction, atomic force microscopy, and scanning electron microscopy demonstrate that the UTFs are orderly periodical layered structure with a thickness of 3.3-3.5 nm per bilayer. The APPV/LDH UTFs exhibit well-defined polarized photoemission characteristic with the maximum luminescence anisotropy of approximately 0.3. Moreover, the UTF exhibit longer fluorescence lifetime (3-3.85-fold) and higher photostability than the drop-casting APPV film under UV irradiation, suggesting that the existence of a LDH monolayer enhances the optical performance of the APPV polyanion. A combination study of electrochemistry and periodic density functional theory was used to investigate the electronic structure of the APPV/LDH system, illustrating that the APPV/LDH UTF is a kind of organic-inorganic hybrid multiple quantum well (MQW) structure with a low band energy of 1.7-1.8 eV, where the valence electrons of APPV can be confined into the energy wells formed by the LDH monolayers effectively. Therefore, this work not only gives a feasible method for fabricating a luminescence ultrathin film but also provides a detailed understanding of the geometric and electronic structures of photoactive polyanions confined between the LDH monolayers.
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Hidróxido de Aluminio/química , Simulación por Computador , Hidróxido de Magnesio/química , Membranas Artificiales , Modelos Químicos , Polivinilos/química , Puntos Cuánticos , Aniones/química , Combinación de Medicamentos , Estructura Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Lavender layers: A poly(p-phenylene) anionic derivate and exfoliated Mg-Al layered double hydroxide monolayers were assembled into ultrathin films with well-defined blue fluorescence (see picture; the numbers indicate the number of bilayers), long-range order, and high photostability. These films work as multiple quantum-well structures for valence electrons.
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Hidróxidos/química , Nanoestructuras/química , Polímeros/química , Fluorescencia , Microscopía Electrónica de RastreoRESUMEN
In recent years layered double hydroxides (LDHs), also known as hydrotalcite-like materials, have attracted considerable interest from both industry and academia. In this article, we discuss methods of preparing LDHs with an emphasis on the way in which particle size and morphology can be controlled with regard to specific target applications; scale-up of one such preparation procedure is also described. In addition, we review selected applications of LDHs developed by our own and other laboratories.
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Hidróxido de Aluminio/química , Ingeniería Biomédica/métodos , Hidróxidos/síntesis química , Hidróxido de Magnesio/química , Magnetismo , Polímeros/química , Microscopía Electrónica de Transmisión , Nanoestructuras/química , Tamaño de la PartículaRESUMEN
Gold nanoclusters (Au NCs) as ultrasmall fluorescent nanomaterials possess discrete electronic energy and unique physicochemical properties, but suffer from relatively low quantum yield (QY) which severely affects their application in displays and imaging. To solve this conundrum and obtain highly-efficient fluorescent emission, 2D exfoliated layered double hydroxide (ELDH) nanosheets were employed to localize Au NCs with a density as high as 5.44 × 10(13) cm(-2), by virtue of the surface confinement effect of ELDH. Both experimental studies and computational simulations testify that the excited electrons of Au NCs are strongly confined by MgAl-ELDH nanosheets, which results in a largely promoted QY as well as prolonged fluorescence lifetime (both â¼7 times enhancement). In addition, the as-fabricated Au NC/ELDH hybrid material exhibits excellent imaging properties with good stability and biocompatibility in the intracellular environment. Therefore, this work provides a facile strategy to achieve highly luminescent Au NCs via surface-confined emission enhancement imposed by ultrathin inorganic nanosheets, which can be potentially used in bio-imaging and cell labelling.
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Oro , Nanopartículas del Metal , Nanoestructuras , Materiales Biocompatibles , Fluorescencia , Células HeLa , HumanosRESUMEN
A simple chemical method to obtain nanopolymers with special morphology is reported. The key to the success of this preparation was the use of layered double hydroxides (LDHs), a two-dimensional host material, as template. Typical procedures include in-situ polymerization of the monomers in the interlayers of the LDH template, followed by the dissolution of LDH sheets so that the formed polymers can be free and collected. The obtained results demonstrate potential of LDHs as tools for the controlled synthesis of nanopolymers with platelike morphology.
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Cristalización/métodos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Poliestirenos/química , Hidróxidos/análisis , Hidróxidos/química , Sustancias Macromoleculares/análisis , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Nanoestructuras/análisis , Tamaño de la Partícula , Polímeros/análisis , Polímeros/química , Poliestirenos/análisisRESUMEN
A targeted photosensitizer used in photodynamic therapy (PDT) was fabricated by incorporation of zinc phthalocyanine (ZnPc) and folic acid (FA) into polyvinylpyrrolidone (PVP) micelles, which exhibits excellent anticancer performance revealed by both in vitro studies and in vivo tests.
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Portadores de Fármacos/administración & dosificación , Ácido Fólico/administración & dosificación , Indoles/administración & dosificación , Neoplasias/tratamiento farmacológico , Compuestos Organometálicos/administración & dosificación , Fotoquimioterapia , Fármacos Fotosensibilizantes/administración & dosificación , Animales , Portadores de Fármacos/química , Ácido Fólico/química , Células Hep G2 , Humanos , Indoles/química , Isoindoles , Masculino , Ratones Endogámicos BALB C , Micelas , Neoplasias/metabolismo , Imagen Óptica , Compuestos Organometálicos/química , Fármacos Fotosensibilizantes/química , Povidona/química , Oxígeno Singlete/química , Luz Solar , Compuestos de ZincRESUMEN
A novel inorganic-organic composite ultrathin film was fabricated by layer-by-layer assembly of naphthol green B (NGB) and layered double hydroxides (LDHs) nanoplatelets, which shows remarkable electrocatalytic behavior for oxidation of ascorbic acid. LDHs nanoplatelets were prepared using a method involving separate nucleation and aging steps (particle size: 25±5 nm; aspect ratio: 2-4) and used as building blocks for alternate deposition with NGB on indium tin oxide (ITO) substrates. UV-vis absorption spectroscopy and XRD display regular and uniform growth of the NGB/LDHs ultrathin film with extremely c-orientation of LDHs nanoplatelets (ab plane of microcrystals parallel to substrates). A continuous and uniform surface morphology was observed by SEM and AFM image. The film modified electrode displays a couple of well-defined reversible redox peaks attributed to Fe(2+)/Fe(3+) in NGB (ΔE(p)=68 mV and I(a)/I(c)=1.1). Moreover, the modified electrode shows a high electrocatalytic activity towards ascorbic acid in the range 1.2-55.2 µM with a detection limit of 0.51 µM (S/N=3). The Michaelis-Menten constant was calculated to be K(M)(app)=67.5 µM.
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Ácido Ascórbico/análisis , Colorantes , Electroquímica/instrumentación , Membranas Artificiales , Catálisis , Electroquímica/métodos , Electrodos , Hidróxidos , Límite de Detección , Oxidación-Reducción , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Inorganic nanoplatelet reinforced polymer films were fabricated via alternate layer-by-layer assembly of layered double hydroxide (LDH) nanoplatelets with poly(vinyl alcohol) (PVA), which showed largely enhanced strength and good ductility simultaneously.
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Hidróxidos/química , Compuestos Inorgánicos/química , Nanocompuestos/química , Nanoestructuras/química , Compuestos Orgánicos/química , Polímeros/química , Alcohol Polivinílico/química , Biomimética , Películas Cinematográficas , Propiedades de Superficie , Resistencia a la TracciónRESUMEN
Induced pluripotent stem cells (iPSCs) can differentiate into mineralizing cells and thus have a great potential in application in engineered bone substitutes with bioactive scaffolds in regeneration medicine. In the current study we characterized and demonstrated the pluripotency and osteogenic differentiation of mouse iPSCs. To enhance the osteogenic differentiation of iPSCs, we then transduced the iPSCs with the potent transcription factor, nuclear matrix protein SATB2. We observed that in SATB2-overexpressing iPSCs there were increased mineral nodule formation and elevated mRNA levels of key osteogenic genes, osterix (OSX), Runx2, bone sialoprotein (BSP) and osteocalcin (OCN). Moreover, the mRNA levels of HoxA2 was reduced after SATB2 overexpression in iPSCs. The SATB2-overexpressing iPSCs were then combined with silk scaffolds and transplanted into critical-size calvarial bone defects created in nude mice. Five weeks post-surgery, radiological and micro-CT analysis revealed enhanced new bone formation in calvarial defects in SATB2 group. Histological analysis also showed increased new bone formation and mineralization in the SATB2 group. In conclusion, the results demonstrate that SATB2 facilitates the differentiation of iPSCs towards osteoblast-lineage cells by repressing HoxA2 and augmenting the functions of the osteoblast determinants Runx2, BSP and OCN.
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Regeneración Ósea/fisiología , Células Madre Pluripotentes Inducidas/fisiología , Proteínas de Unión a la Región de Fijación a la Matriz/metabolismo , Seda/química , Cráneo/patología , Ingeniería de Tejidos/instrumentación , Andamios del Tejido/química , Factores de Transcripción/metabolismo , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/metabolismo , Diferenciación Celular , Células Cultivadas , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Células Madre Pluripotentes Inducidas/citología , Sialoproteína de Unión a Integrina/genética , Sialoproteína de Unión a Integrina/metabolismo , Ensayo de Materiales , Proteínas de Unión a la Región de Fijación a la Matriz/genética , Ratones , Ratones Desnudos , Osteocalcina/genética , Osteocalcina/metabolismo , Cráneo/citología , Cráneo/metabolismo , Factor de Transcripción Sp7 , Ingeniería de Tejidos/métodos , Factores de Transcripción/genética , Transducción Genética , Cicatrización de Heridas/fisiologíaRESUMEN
This paper reports the fabrication of a bi-protein/layered double hydroxide (LDH) ultrathin film in which hemoglobin (HB) and horseradish peroxidase (HRP) molecules were assembled alternately with LDH nanosheets via the layer-by-layer (LBL) deposition technique, and its electrocatalytic performances for oxidation of catechol were demonstrated. The results of XRD indicate that the HB-HRP/LDH ultrathin film possesses a long range stacking order in the normal direction of the substrate, with the two proteins accommodated in the LDH gallery respectively as monolayer arrangement. SEM images show that the film surface exhibits a continuous and uniform morphology, and AFM reveals the Root-Mean-Square (RMS) roughness of â¼10.2 nm for the film. A stable direct electrochemical redox behavior of the proteins was successfully obtained for the HB-HRP/LDH film modified electrode. In addition, it exhibits remarkable electrocatalytic activity towards oxidation of catechol, based on the synergistic effect of the two proteins. The catechol biosensor in this work displays a wide linear response range (6-170 µM, r=0.999), low detection limit (5 µM), high sensitivity and good reproducibility.
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Técnicas Biosensibles/instrumentación , Catecoles/análisis , Catecoles/química , Conductometría/instrumentación , Hemoglobinas/química , Peroxidasa de Rábano Silvestre/química , Membranas Artificiales , Microelectrodos , Catálisis , Diseño de Equipo , Análisis de Falla de Equipo , Hidróxidos/química , Unión ProteicaRESUMEN
We report the preparation of a reversible photoresponsive ultrathin film containing a photoactive azobenzene polymer poly{1-4[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl sodium salt} (PAZO) and exfoliated layered double hydroxide (LDH) nanosheets using a layer-by-layer (LBL) self-assembly technique. Alternate irradiation with UV and visible light (lambda > 450 nm) results in a reversible switching between the trans isomer and the cis-rich photostationary state of the azobenzene group with concomitant significant changes in film color. Fluorescence polarization measurements indicated that the orientation of the azobenzene chromophores in the LDH matrix undergoes a reversible realignment during the photoisomerization processes. Photoisomerization induced by alternate UV and visible light irradiation was accompanied by reversible morphological changes of the LBL film, observable by atomic force microscopy (AFM). Molecular dynamics (MD) studies demonstrated that the LDH monolayers allow sufficient free space for the PAZO to undergo isomerization of its azobenzene chromophores. The reversible photoalignment of PAZO was also followed by MD simulations, and the results are in reasonable agreement with the experimental findings, further validating the configurational and orientational changes proposed for PAZO during the reversible photoprocess. It has been demonstrated that the host (LDH nanosheet)-guest (PAZO) interactions are key factors in determining the reversible photoresponsive performances of the film, since the comparative pristine PAZO film shows no such properties. Therefore, the incorporation of a photoactive moiety within the inorganic nanosheets of LDH by the LBL technique provides an attractive and feasible methodology for creating novel light-sensitive materials and devices with potential read-write capabilities.
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Compuestos Azo/química , Hidróxidos/química , Polímeros/química , Polarización de Fluorescencia , Isomerismo , Microscopía de Fuerza Atómica , Simulación de Dinámica Molecular , Nanoestructuras/química , Rayos UltravioletaRESUMEN
We report a biomorphic hierarchical mixed metal oxide (MMO) framework through a biotemplated synthesis method. A uniform Al(2)O(3) coating was deposited on the surface of the biotemplate with an atomic layer deposition (ALD) process, and the film of ZnAl-layered double hydroxide (ZnAl-LDH), which faithfully inherits the surface structure of the biotemplate, was prepared by an in situ growth technique. Subsequently, a polycrystal ZnAl-MMO framework obtained by calcination of the LDH precursor has been demonstrated as an effective and recyclable photocatalyst for the decomposition of dyes in water, owing to its rather high specific surface area and hierarchical distribution of pore size. Therefore, the new strategy reported in this work can be used to fabricate a variety of biomorphic LDHs as well as MMO frameworks through replication of complicated and hierarchical biological structures for the purpose of catalysis, adsorbents, and other potential applications.
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Óxido de Aluminio/química , Materiales Biocompatibles/química , Cristalización/métodos , Hidróxidos/química , Nanoestructuras/química , Nanotecnología/métodos , Zinc/química , Óxido de Aluminio/efectos de la radiación , Materiales Biocompatibles/efectos de la radiación , Catálisis , Hidróxidos/efectos de la radiación , Luz , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Nanoestructuras/efectos de la radiación , Nanoestructuras/ultraestructura , Tamaño de la Partícula , Fotoquímica/métodos , Propiedades de Superficie , Zinc/efectos de la radiaciónRESUMEN
OBJECTIVE: To study the distribution and expression of fibromodulin, decorin and biglycan in developing normal periodontal tissues, so as to understand its role in periodontal tissue formation. METHODS: Thirty six BALB/c mice in different developing stages were killed and their bilateral mandibular first molars with surrounding alveolar bones and gingival tissues were taken out, Power Vision two steps immunohistochemical method with anti-fibromodulin, anti-decorin and anti-biglycan was used to detect the tissue distribution and cellular localization of fibromodulin and related proteoglycans, decorin and biglycan. RESULTS: Fibromodulin was strongly expressed in the subcutaneous gingival connective tissue, periodontal ligament, mainly in gingival and periodontal fibroblasts as well as their matrices. Strong expression was also noted in the area close to the interfaces of periodontal ligament-alveolar bone and periodontal ligament-cementum. Decorin was strongly expressed in the area of gingival connective tissue, periodontal ligament and the surface of alveolar bone, while biglycan was stained evidently in gingival connective tissue throughout the period of investigation, but negative in the surface of alveolar bone and osteoblasts. CONCLUSIONS: Fibromodulin may interact with decorin and biglycan to regulate the network formation of gingival connective tissues and periodontal collagen fibers, and may be involved in mineralization of the alveolar bone and cementum.
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Proceso Alveolar/citología , Proteínas de la Matriz Extracelular/análisis , Encía/química , Osteoblastos/química , Ligamento Periodontal/química , Proteoglicanos/análisis , Proceso Alveolar/crecimiento & desarrollo , Animales , Biglicano , Decorina , Fibromodulina , Encía/crecimiento & desarrollo , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Ligamento Periodontal/crecimiento & desarrollo , Germen Dentario/químicaRESUMEN
After being impregnated in the solution containing Mg(NO3)2 x 6H2O, gamma-Al2O3 was dried and calcined at 500 degrees C which results in the production of a bactericide, highly dispersed MgO loaded on the surface of gamma-Al2O3. The threshold value of the monolayer dispersion of MgO on gamma-Al2O3 is 14.97%, and MgO crystal formed when the load amount beyond this value. The samples with different load amount were characterized by X-ray Diffraction (XRD), Low-temperature N2 adsorption-desorption, Inductively Coupled Plasma (ICP) and High Resolution Scan Electronic Microscope (SEM). The results showed that these MgO microcrystals are highly dispersed and have regular size in the range of 4 to 10.8 nm. The specific surface, pore volume and pore size of the sample decreases with the increase of load amount. It is demonstrated that gamma-Al2O3 with highly dispersed MgO on the surface is efficient bactericide, and the one with 20% load amount of MgO can kill more than 99% bacteria and spore cells.