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1.
Colloids Surf B Biointerfaces ; 161: 42-50, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29040833

RESUMO

A mixed self-assembled monolayer (SAM) of an initiator (3-(2-bromo-2-isobutyryloxy)propyl triethoxysilane) for atom transfer radical polymerization (ATRP) and an agent (6-(triethoxysilyl)hexyl 2-(((methylthio)carbonothioyl)thio)-2-phenylacetate) for reversible addition-fragmentation chain transfer (RAFT) polymerization was constructed on the surface of a silicon wafer or glass plate by a silane coupling reaction. When a UV light at 254nm was irradiated at the mixed SAM through a photomask, the surface density of the bromine atom at the end of BPE in the irradiated region was drastically reduced by UV-driven scission of the BrC bond, as observed by X-ray photoelectron spectroscopy. Consequently, the surface-initiated (SI)-ATRP of 2-ethylhexyl methacrylate (EHMA) was used to easily construct the poly(EHMA) (PEHMA) brush domain. Subsequently, SI-RAFT polymerization of a zwitterionic vinyl monomer, carboxymethyl betaine (CMB), was performed. Using the sequential polymerization, the PCMB and PEHMA brush domains on the solid substrate could be very easily patterned. Patterning proteins and cells with the binary polymer brush is expected because the PCMB brush indicated strong suppression of protein adsorption and cell adhesion, and the PEHMA brush had non-polar properties. This technique is very simple and useful for regulating the shape and size of bio-fouling and anti-biofouling domains on solid surfaces.


Assuntos
Materiais Biocompatíveis/química , Polimerização/efeitos da radiação , Polímeros/química , Raios Ultravioleta , Adsorção/efeitos da radiação , Animais , Betaína/química , Materiais Biocompatíveis/farmacologia , Incrustação Biológica/prevenção & controle , Adesão Celular/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Espectroscopia Fotoeletrônica , Propriedades de Superfície
2.
ACS Nano ; 11(11): 10903-10913, 2017 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-29112378

RESUMO

Strong electric fields are known to influence the properties of molecules as well as materials. Here we show that by changing the orientation of an externally applied electric field, one can locally control the mixing behavior of two molecules physisorbed on a solid surface. Whether the starting two-component network evolves into an ordered two-dimensional (2D) cocrystal, yields an amorphous network where the two components phase separate, or shows preferential adsorption of only one component depends on the solution stoichiometry. The experiments are carried out by changing the orientation of the strong electric field that exists between the tip of a scanning tunneling microscope and a solid substrate. The structure of the two-component network typically changes from open porous at negative substrate bias to relatively compact when the polarity of the applied bias is reversed. The electric-field-induced mixing behavior is reversible, and the supramolecular system exhibits excellent stability and good response efficiency. When molecular guests are adsorbed in the porous networks, the field-induced switching behavior was found to be completely different. Plausible reasons behind the field-induced mixing behavior are discussed.


Assuntos
Campos Eletromagnéticos , Nanoestruturas/efeitos da radiação , Propriedades de Superfície/efeitos da radiação , Adsorção/efeitos da radiação , Animais , Bismuto/química , Eletricidade , Modelos Moleculares , Nanoestruturas/química , Porosidade/efeitos da radiação
3.
J Phys Chem B ; 121(33): 7797-7802, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28753013

RESUMO

In this article, we have studied the binding of different naturally occurring hemoglobin (Hb) variants on erythrocyte skeletal protein, spectrin surface using the label free nondestructive second harmonic light scattering (SHLS) technique in aqueous buffer. Hemoglobin variants like sickle hemoglobin (HbS) and hemoglobin E (HbE) were chosen as they associate with sickle cell disease and HbEß-thalassemia, respectively, and their interaction with spectrin is compared with normal adult hemoglobin (HbA). The concentration dependent change in the second harmonic light intensity from nanomolar spectrin solution has been measured after addition of small aliquots of hemoglobins. From the second harmonic titration data, the binding constant is calculated using a modified Langmuir adsorption model of hemoglobin binding to the spectrin surface. Interestingly, it is found that the binding constant for HbE (13.8 × 108 M-1) is 1 order of magnitude higher than that of HbS (1.6 × 108 M-1) or HbA (2.1 × 108 M-1) which indicates higher affinity of HbE for spectrin compared to HbA and HbS. The number of the Hb molecules bound to the spectrin surface was estimated to be of the order of hundred's which is determined for the first time.


Assuntos
Hemoglobinas/química , Luz , Espalhamento de Radiação , Espectrina/química , Adsorção/efeitos da radiação , Ligação Proteica/efeitos da radiação , Propriedades de Superfície
4.
IET Nanobiotechnol ; 11(3): 317-328, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28476990

RESUMO

This study discusses about the biosorption of Cr(VI) ion from aqueous solution using ultrasonic assisted Spirulina platensis (UASP). The prepared UASP biosorbent was characterised by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller, scanning electron spectroscopy and energy dispersive X-ray and thermogravimetric analyses. The optimum condition for the maximum removal of Cr(VI) ions for an initial concentration of 50 mg/l by UASP was measured as: adsorbent dose of 1 g/l, pH of 3.0, contact time of 30 min and temperature of 303 K. Adsorption isotherm, kinetics and thermodynamic parameters were calculated. Freundlich model provided the best results for the removal of Cr(VI) ions by UASP. The adsorption kinetics of Cr(VI) ions onto UASP showed that the pseudo-first-order model was well in line with the experimental data. In the thermodynamic study, the parameters like Gibb's free energy, enthalpy and entropy changes were evaluated. This result explains that the adsorption of Cr(VI) ions onto the UASP was exothermic and spontaneous in nature. Desorption of the biosorbent was done using different desorbing agents in which NaOH gave the best result. The prepared material showed higher affinity for the removal of Cr(VI) ions and this may be an alternative material to the existing commercial adsorbents.


Assuntos
Cromo/isolamento & purificação , Modelos Químicos , Sonicação/métodos , Spirulina/química , Spirulina/efeitos da radiação , Poluentes Químicos da Água/isolamento & purificação , Adsorção/efeitos da radiação , Biodegradação Ambiental , Cromo/química , Simulação por Computador , Íons/química , Íons/isolamento & purificação , Cinética , Termodinâmica , Purificação da Água
5.
J Nanosci Nanotechnol ; 16(5): 4342-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27483755

RESUMO

Solar photocatalytic degradation of organic water pollutants can be used to degrade toxic organic pollutants in water. In this study, potassium titanate nanofibres were synthesized by an aqueous peroxide route at high pH and examined as photocatalysts for photodegradation of methylene blue (MB) using a solar simulator. Initially, MB was adsorbed on the surface of potassium polytitanates to achieve adsorption equilibrium before the photocatalysts were illuminated using solar simulator. The results showed that potassium polytitanate nanofibres were effective adsorbents of MB and also facilitated its photocatalytic degradation. Sulphate ion evolution during photocatalysis confirmed that some mineralisation occurred and hence photo-oxidative degradation of MB took place. The optimum operational conditions for the photocatalytic degradation of MB were found at 0.05 g/L of photocatalyst load, 10 mg/L MB and pH 7. The stability and regeneration of the photocatalyst specimen was also studied for 3 degradation cycles using adsorption/photocatalysis model. Morphological structure analysis of potassium titanate showed nanocrystallines structure of longitudinally-oriented isolated fibre with a length up to several micrometres with diameters ranging from 10 to 20 nanometres.


Assuntos
Azul de Metileno/química , Nanopartículas/química , Energia Solar , Titânio/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção/efeitos da radiação , Catálise/efeitos da radiação , Azul de Metileno/isolamento & purificação , Azul de Metileno/efeitos da radiação , Nanopartículas/efeitos da radiação , Nanopartículas/ultraestrutura , Titânio/efeitos da radiação , Poluentes Químicos da Água/isolamento & purificação
6.
J Nanosci Nanotechnol ; 16(4): 4224-32, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27451790

RESUMO

We studied the dispersity of multi-walled carbon nanotubes (MWNTs) combined with different metal- lic particles (Ni and Fe). An ultrasonic-assisted water-bath dispersion process was used to dis- perse the metal-coated MWNTs in different solutions and the dispersity was measured using an ultraviolet-visible spectrophotometer. The dispersity and morphology of the MWNTs were characterized using field-emission scanning electron microscopy (FE-SEM) together with digital image processing technology. Effects of dispersant type (sodium dodecyl benzene sulfonate (SDBS), oleic acid, and polymer (TNEDIS)) and surfactant dosage on the dispersity of the metal-coated MWNTs were investigated under controlled and uncontrolled temperatures and results were compared with those from the untreated MWNTs. The results showed that the negative effects of temperature on the ultrasonic dispersion process could be eliminated through a temperature-controlled system. Moreover, the TNEDIS, SDBS, and oleic acid were arranged in the descending order of the dispersion effect degree. The untreated MWNTs, Ni-coated MWNTs, and Fe-coated MWNTs were arranged in the descending degree of dispersity order. Since the metal coating makes the MWNTs harder and more fragile, the metal-coated MWNTs are more likely to fracture during the ultrasonic dispersion process.


Assuntos
Temperatura Alta , Metais/química , Nanotubos de Carbono/química , Nanotubos de Carbono/efeitos da radiação , Sonicação/métodos , Tensoativos/química , Adsorção/efeitos da radiação , Coloides/química , Coloides/efeitos da radiação , Cristalização/métodos , Ondas de Choque de Alta Energia , Teste de Materiais , Nanotubos de Carbono/ultraestrutura
7.
Water Sci Technol ; 73(4): 881-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26901732

RESUMO

Herein the degradation of malachite green (MG) dye from aqueous medium by vanadium doped zinc oxide (ZnO:V3%) nanopowder was investigated. The specific surface area and pore volume of the nanopowder was characterized by nitrogen adsorption method. Batch experimental procedures were conducted to investigate the adsorption and photocatalytic degradation of MG dye. Adsorption kinetics investigations were performed by varying the amount of the catalyst and the initial dye concentrations. Adsorption and photocatalytic degradation data were modeled using the Lagergren pseudo-first-order and second-order kinetic equation. The results showed that the ZnO:V3% nanopowder was particularly effective for the removal of MG and data were found to comply with Lagergreen pseudo-first-order kinetic model.


Assuntos
Recuperação e Remediação Ambiental/métodos , Nanopartículas/química , Corantes de Rosanilina/química , Vanádio/química , Poluentes Químicos da Água/química , Óxido de Zinco/química , Adsorção/efeitos da radiação , Catálise/efeitos da radiação , Recuperação e Remediação Ambiental/instrumentação , Concentração de Íons de Hidrogênio , Cinética , Luz
8.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 50(7): 428-32, 2015 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-26564748

RESUMO

OBJECTIVE: To study the adsorption behavior of bovine serum albumin (BSA) and fibrinogen (Fg) and the competition of them on titanium before and after ultraviolet (UV)-photofunctionalization, and to provide the evidence of photofunctionalization on the surface modification of titanium implants. METHODS: Titanium disks and sensors of quartz crystal microbalance-D (QCM-D) were stored and sealed in the dark for 4 weeks before being divided into two groups, namely the UV-treated group and control group. Samples in the UV-treated group were treated with UV rays for 48 hours. Then the Fg adsorbing property of disks in both groups was tested at 1, 12 and 24 h. Protein films of Fg and BSA formed on QCM sensors after 1 h incubation were imaged via atomic force microscopy (AFM). Then with QCM-D, for both surfaces the adsorption of Fg and BSA as well as the competition between them was tested by introducing proteins with different sequences. RESULTS: After being incubated for 1 and 12 h, UV-treated group attracted more Fg[(0.250 ± 0.005) and (0.172 ± 0.006) mg] than control group did [(0.207 ± 0.004) and (0.144 ± 0.004) mg] (P < 0.05). However, after 24 h incubation, Fg residual on the UV-treated group [(0.080 ± 0.003) mg] was smaller than that in the control group [(0.127 ± 0.004) mg] (P < 0.05). AFM showed protein clustered more densely on UV-treated surfaces than control surfaces and QCM displayed the same result. In addition, when Fg was introduced into QCM-D after BSA, the mass of protein film increased on both surfaces. However, when BSA was introduced after Fg, the mass of protein film on the control group had no change, but slightly decrease on the UV-treated group. CONCLUSIONS: UV-photofunctionalization promotes protein adsorption but has no influence on the competition between Fg and BSA.


Assuntos
Implantes Dentários , Fibrinogênio , Soroalbumina Bovina , Titânio/efeitos da radiação , Raios Ultravioleta , Adsorção/efeitos da radiação , Microscopia de Força Atômica , Técnicas de Microbalança de Cristal de Quartzo , Propriedades de Superfície , Fatores de Tempo , Titânio/química
9.
J Agric Food Chem ; 63(38): 8391-8, 2015 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-26345112

RESUMO

The botanical insecticide azadirachtin was incorporated in alginate-based granules to obtain controlled release formulations (CRFs). The basic formulation [sodium alginate (1.47%) - azadirachtin (0.28%) - water] was modified by the addition of biosorbents, obtaining homogeneous hybrid hydrogels with high azadirachtin entrapment efficiency. The effect on azadirachtin release rate caused by the incorporation of biosorbents such as lignin, humic acid, and olive pomace in alginate formulation was studied by immersion of the granules in water under static conditions. The addition of the biosorbents to the basic alginate formulation reduces the rate of release because the lignin-based formulation produces a slower release. Photodegradation experiments showed the potential of the prepared formulations in protecting azadirachtin against simulated sunlight, thus improving its stability. The results showed that formulation prepared with lignin provided extended protection. Therefore, this study provides a new procedure to encapsulate the botanical insecticide azadirachtin, improving its delivery and photostability.


Assuntos
Alginatos/química , Química Farmacêutica/métodos , Preparações de Ação Retardada/química , Inseticidas/química , Limoninas/química , Adsorção/efeitos da radiação , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Cinética , Fotólise
10.
Sci Rep ; 5: 13354, 2015 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-26306638

RESUMO

In this work, the behavior of protein molecules adsorbed on TiO2 nanodots films are modulated through the light responses of the nanodots. TiO2 nanodots films are first prepared through phase separation induced self assembly. Then, bovine serum albumin (BSA) is adsorbed on TiO2 nanodots films and exposed to ultraviolet (365 nm) illumination. It is found the conformation of surface-bound BSA molecules changes with ultraviolet illumination. Moreover, the BSA molecules conjugate to the surface-bound molecules, which are in the overlayer, are released. The reason is ascribed to that TiO2 nanodots absorb ultraviolet and result in the increase of surface hydroxyl groups on nanodots. Such increase further leads to intensified attraction of -NH3 groups in the surface-bound BSA molecules. That not only changes the conformation of the surface-bound BSA molecules, but also weaken the conjugation between surface-bound molecules and other BSA molecules in the overlayer. Eventually, the overlayer of BSA molecules is released. It is believed that such protein conformation variation and release behavior induced through light responses of TiO2 nanodots are crucial in understanding the biomedical performance of TiO2 nanostructures. Also, it could be widely utilized in tailoring of the materials-protein interactions.


Assuntos
Membranas Artificiais , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Soroalbumina Bovina/química , Soroalbumina Bovina/efeitos da radiação , Titânio/química , Adsorção/efeitos da radiação , Sítios de Ligação/efeitos da radiação , Luz , Teste de Materiais , Tamanho da Partícula , Ligação Proteica/efeitos da radiação , Conformação Proteica/efeitos da radiação , Doses de Radiação , Propriedades de Superfície , Titânio/efeitos da radiação , Raios Ultravioleta
11.
Invest Radiol ; 50(11): 772-84, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26135018

RESUMO

OBJECTIVE: The objective of this study was to optically verify the dynamic behaviors of adherent microbubbles in large blood vessel environments in response to a new ultrasound technique using modulated acoustic radiation force. MATERIALS AND METHODS: Polydimethylsiloxane (PDMS) flow channels coated with streptavidin were used in targeted groups to mimic large blood vessels. The custom-modulated acoustic radiation force beam sequence was programmed on a Verasonics research scanner. In vitro experiments were performed by injecting a biotinylated lipid-perfluorobutane microbubble dispersion through flow channels. The dynamic response of adherent microbubbles was detected acoustically and simultaneously visualized using a video camera connected to a microscope. In vivo verification was performed in a large abdominal blood vessel of a murine model for inflammation with injection of biotinylated microbubbles conjugated with P-selectin antibody. RESULTS: Aggregates of adherent microbubbles were observed optically under the influence of acoustic radiation force. Large microbubble aggregates were observed solely in control groups without targeted adhesion. Additionally, the dispersion of microbubble aggregates were demonstrated to lead to a transient acoustic signal enhancement in control groups (a new phenomenon we refer to as "control peak"). In agreement with in vitro results, the control peak phenomenon was observed in vivo in a murine model. CONCLUSIONS: This study provides the first optical observation of microbubble-binding dynamics in large blood vessel environments with application of a modulated acoustic radiation force beam sequence. With targeted adhesion, secondary radiation forces were unable to produce large aggregates of adherent microbubbles. Additionally, the new phenomenon called control peak was observed both in vitro and in vivo in a murine model for the first time. The findings in this study provide us with a better understanding of microbubble behaviors in large blood vessel environments with application of acoustic radiation force and could potentially guide future beam sequence designs or signal processing routines for enhanced ultrasound molecular imaging.


Assuntos
Vasos Sanguíneos/química , Vasos Sanguíneos/efeitos da radiação , Técnicas de Imagem por Elasticidade/métodos , Fluorcarbonetos/química , Fluorcarbonetos/efeitos da radiação , Microbolhas , Adsorção/efeitos da radiação , Animais , Vasos Sanguíneos/diagnóstico por imagem , Meios de Contraste/química , Meios de Contraste/efeitos da radiação , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Doses de Radiação , Som
12.
ACS Appl Mater Interfaces ; 7(13): 7389-96, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25776274

RESUMO

In this paper, we report on the synthesis of FeCo/Cu multisegmented nanowires by means of pulse electrodeposition in nanoporous anodic aluminum oxide arrays supported on silicon chips. By adjustment of the electrodeposition conditions, such as the pulse scheme and the electrolyte, alternating segments of Cu and ferromagnetic FeCo alloy can be fabricated. The segments can be built with a wide range of lengths (15-150 nm) and exhibit a close-to-pure composition (Cu or FeCo alloy) as suggested by energy-dispersive X-ray mapping results. The morphology and the crystallographic structure of different nanowire configurations have been assessed thoroughly, concluding that Fe, Co, and Cu form solid solution. Magnetic characterization using vibrating sample magnetometry and magnetic force microscopy reveals that by introduction of nonmagnetic Cu segments within the nanowire architecture, the magnetic easy axis can be modified and the reduced remanence can be tuned to the desired values. The experimental results are in agreement with the provided simulations. Furthermore, the influence of nanowire magnetic architecture on the magnetically triggered protein desorption is evaluated for three types of nanowires: Cu, FeCo, and multisegmented FeCo15nm/Cu15nm. The application of an external magnetic field can be used to enhance the release of proteins on demand. For fully magnetic FeCo nanowires the applied oscillating field increased protein release by 83%, whereas this was found to be 45% for multisegmented FeCo15nm/Cu15nm nanowires. Our work suggests that a combination of arrays of nanowires with different magnetic configurations could be used to generate complex substance concentration gradients or control delivery of multiple drugs and macromolecules.


Assuntos
Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Nanofios/química , Nanofios/efeitos da radiação , Proteínas/química , Absorção Fisico-Química/efeitos da radiação , Adsorção/efeitos da radiação , Cobalto/química , Cobre/química , Cristalização/métodos , Galvanoplastia/métodos , Ferro/química , Campos Magnéticos , Teste de Materiais , Nanopartículas Metálicas/ultraestrutura , Nanofios/ultraestrutura , Ligação Proteica/efeitos da radiação , Proteínas/efeitos da radiação
13.
Food Chem ; 172: 56-62, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25442523

RESUMO

A novel photoresponsive molecularly imprinted polymer (MIP) was developed for the selective extraction of guanine from complex samples. The photoresponsive MIP was fabricated using guanine as the template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as the functional monomer, and water-soluble triethanolamine trimethacrylate as the cross-linker. The MIP displayed good selectivity toward guanine with a dissociation constant of (2.70 ± 0.16) × 10(-5) mol L(-1) in aqueous media. The density of the guanine-specific receptor sites in the MIP material was (4.49 ± 0.22)µmol g(-1). Quantitatively release and uptake of guanine by the MIP occurred with irradiation at 365 and 440 nm, respectively. The MIP could efficiently extract guanine from beer and then release it into aqueous media under photocontrol. This method could be used for selective separation and subsequent determination of a specific analytes from complex samples.


Assuntos
Cerveja/análise , Guanina/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Adsorção/efeitos da radiação , Guanina/química , Impressão Molecular , Polímeros/síntese química , Extração em Fase Sólida/instrumentação
14.
Molecules ; 19(12): 19557-72, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25432008

RESUMO

Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcoming recombination in photocatalysis in this era of nanoparticle composites. Their relationships are considered here. A review of key literature is accompanied by a presentation of three new experiments within the overall aim of assessing the relation of these strategies. The cases presented include: A/S by a high silica zeolite/TiO2 composite, charge transfer (CT) between phases in a TiO2/WO3 composite and both A/S and CT by composites of TiO2 with powered activated carbon (AC) and single-walled carbon nanotubes (SWCNT). The opportunities presented by the two strategies for moving toward photocatalysts that could support applications for the removal of contaminants from drinking water or that lead to a practical adsorbent for organics that could be regenerated photocatalytically link this discussion to ongoing research here.


Assuntos
Elétrons , Luz , Purificação da Água/métodos , Adsorção/efeitos da radiação , Carbono/isolamento & purificação , Catálise/efeitos da radiação , Contagem de Colônia Microbiana , Enterobacteriaceae/isolamento & purificação , Cinética , Temperatura , Titânio/química , Zeolitas/química
15.
J R Soc Interface ; 11(97): 20140453, 2014 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-24920120

RESUMO

The remarkable ability of some plants and animals to cling strongly to substrates despite relatively weak interfacial bonds has important implications for the development of synthetic adhesives. Here, we examine the origins of large detachment forces using a thin elastomer tape adhered to a glass slide via van der Waals interactions, which serves as a model system for geckos, mussels and ivy. The forces required for peeling of the tape are shown to be a strong function of the angle of peeling, which is a consequence of frictional sliding at the edge of attachment that serves to dissipate energy that would otherwise drive detachment. Experiments and theory demonstrate that proper accounting for frictional sliding leads to an inferred work of adhesion of only approximately 0.5 J m(-2) (defined for purely normal separations) for all load orientations. This starkly contrasts with the interface energies inferred using conventional interface fracture models that assume pure sticking behaviour, which are considerably larger and shown to depend not only on the mode-mixity, but also on the magnitude of the mode-I stress intensity factor. The implications for developing frameworks to predict detachment forces in the presence of interface sliding are briefly discussed.


Assuntos
Adesividade , Fricção , Membranas Artificiais , Modelos Teóricos , Eletricidade Estática , Adsorção/efeitos da radiação , Simulação por Computador , Módulo de Elasticidade , Movimento (Física) , Doses de Radiação , Propriedades de Superfície
16.
Adv Mater ; 26(24): 4087-92, 2014 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-24719300

RESUMO

Functional cellulose substrates with tetrazole moieties are generated to serve as universal platforms for the spatio-temporal immobilization of synthetic ultra-low fouling polymer brushes and protein species via a nitrile imine-mediated tetrazole-ene cycloaddition (NITEC)-based protocol. Poly(carboxybetaine acrylamide) brushes are grafted from initiators photo-patterned by NITEC utilizing single electron transfer living radical polymerization. Streptavidin is photo-immobilized with remarkable efficiency, opening the possibility to generate new materials for biomedical and biosensing applications.


Assuntos
Técnicas Biossensoriais/métodos , Imunoensaio/métodos , Impressão Molecular/métodos , Papel , Fotografação/métodos , Análise Serial de Proteínas/métodos , Estreptavidina/química , Adsorção/efeitos da radiação , Teste de Materiais , Fotoquímica/métodos , Propriedades de Superfície/efeitos da radiação
17.
ScientificWorldJournal ; 2013: 641420, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24311980

RESUMO

Calcium oxide (CaO) nanoparticles are known to exhibit unique property due to their high adsorption capacity and good catalytic activity. In this work the CaO nanocatalysts were prepared by hydrothermal method using anionic surfactant, sodium dodecyl sulphate (SDS), as a templating agent. The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO. The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques. The catalytic efficiencies of these nanocatalysts were studied for the photodegradation of 2,4,6-trinitrophenol (2,4,6-TNP), which is an industrial pollutant, spectrophotometrically. The effect of surfactant and temperature on size of nanocatalysts was also studied. The smallest particle size and highest percentage of degradation were observed at critical micelle concentration of the surfactant. The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.


Assuntos
Óxido de Alumínio/química , Compostos de Cálcio/química , Óxidos/química , Picratos/química , Picratos/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção/efeitos da radiação , Óxido de Alumínio/efeitos da radiação , Compostos de Cálcio/efeitos da radiação , Catálise , Luz , Micelas , Óxidos/efeitos da radiação , Picratos/efeitos da radiação , Dodecilsulfato de Sódio/química , Dodecilsulfato de Sódio/efeitos da radiação , Água/química , Poluentes Químicos da Água/efeitos da radiação
18.
ScientificWorldJournal ; 2013: 346910, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24235885

RESUMO

In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils.


Assuntos
Metais Pesados/isolamento & purificação , Compostos Orgânicos/isolamento & purificação , Poluentes do Solo/isolamento & purificação , Solo/química , Adsorção/efeitos da radiação , Biodegradação Ambiental , Campos Eletromagnéticos , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/química , Metais Pesados/efeitos da radiação , Compostos Orgânicos/química , Compostos Orgânicos/efeitos da radiação , Poluentes do Solo/química , Poluentes do Solo/efeitos da radiação
19.
J Nanosci Nanotechnol ; 13(11): 7596-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24245299

RESUMO

SnO2 nanostuctures were formed on indium-tin-oxide (ITO)-coated glass substrates by using an electrochemical deposition (ECD) method. X-ray photoelectron spectroscopy (XPS) spectra showed the existence of elemental Sn and O in the samples, indicative of the formation of SnO2 materials. An XPS spectrum showing the O 1s peak at a binding energy of 531.5 eV indicated that the oxygen atoms were bonded to the SnO2. Field-emission scanning electron microscopy (FE-SEM) images showed that the samples formed by using the ECD method had SnO2 nanostructures with a size between 280 and 350 nm. FE-SEM images showed that the size of the SnO2 nanostructures formed at 65 degrees C for 30 min increased with decreasing applied voltage. X-ray diffraction (XRD) patterns showed that the SnO2 nanostrucures had tetragonal structures with cell parameters of a = 4.738 A and c = 3.187 A. XRD results showed that the peak intensity of the (110) plane increased with decreasing applied voltage, indicative of a preferencial orientation of the (110) plane.


Assuntos
Cristalização/métodos , Galvanoplastia/métodos , Vidro/química , Nanopartículas Metálicas/química , Compostos de Estanho/química , Compostos de Estanho/efeitos da radiação , Adsorção/efeitos da radiação , Campos Eletromagnéticos , Vidro/efeitos da radiação , Teste de Materiais , Nanopartículas Metálicas/efeitos da radiação , Nanopartículas Metálicas/ultraestrutura , Tamanho da Partícula , Doses de Radiação
20.
Int J Nanomedicine ; 8: 3927-35, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24143097

RESUMO

PURPOSE: The purpose of this study was to develop a novel and continuous method for preparing a nanosized particle of drug crystals and to characterize its properties. MATERIALS AND METHODS: A new apparatus was introduced to crystallize nanosized drug crystals of amitriptyline hydrochloride as a model drug. The samples were prepared in the pure state by ultrasonic spray, and elaborated deposition was completed via electrostatic adsorption. Scanning electron microscopy, X-ray powder diffraction, and atomic force microscopy were used to characterize the size of the particles; this was subsequently followed by differential scanning calorimetry. RESULTS AND DISCUSSION: Nanoparticles of drug crystals were successfully prepared. The size of the drug crystals ranged from 20 nm to 400 nm; the particle size of amitriptyline hydrochloride was approximately 71 nm. The particles were spherical and rectangular in shape. Moreover, the melting point of the nanoparticles decreased from 198.2°C to 196.3°C when compared to raw particle crystals. Furthermore, the agglomeration effect was also attenuated as a result of electrostatic repulsion among each particle when absorbed, and depositing on the inner wall of the gathering unit occurred under the electrostatic effect. CONCLUSION: Ultrasonic spray-assisted electrostatic adsorption is a very effective and continuous method to produce drug nanocrystals. This method can be applied to poorly water-soluble drugs, and it can also be a very effective alternative for industrial production. Once the working parameters are given, drug nanocrystals will be produced continuously.


Assuntos
Amitriptilina/síntese química , Amitriptilina/isolamento & purificação , Cristalização/métodos , Composição de Medicamentos/métodos , Galvanoplastia/métodos , Nanopartículas/química , Sonicação/métodos , Adsorção/efeitos da radiação , Amitriptilina/efeitos da radiação , Ondas de Choque de Alta Energia , Nanopartículas/efeitos da radiação , Nanopartículas/ultraestrutura , Tamanho da Partícula , Eletricidade Estática
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