Search

Bifunctional periodic mesoporous organosilica materials with and without cobalt ion incorporation were synthesized by co-condensation of 1,2-bistrimethoxysilylethane (BTME) with 3-aminopropyltriethoxysilane (APTS) in the presence of cetyltrimethylammonium bromide. Cobalt was incorporated onto APTS-modified ethylene-bridged silica materials by in situ and by incipient wetness addition methods. The periodicity of the new materials is indicated by the presence of low angle diffraction peaks found in the XRD profiles (pore size ca. 40 nm). The surface area, pore volume and pore diameter of the new ethylene-bridged silica materials decreased with increasing loading of APTS as well as after cobalt incorporation. Thermogravimetric analysis and Raman spectroscopy show that the surfactant is removed by solvent extraction. Cobalt ion incorporation is confirmed by Raman spectroscopy and UV-vis diffuse reflectance spectroscopy.

[Display omitted] • Silylation of the clay with 3‑aminpropyltriethoxysilane (APTES). • Modification of silylated clay by grafting of glutaraldehyde (GA), tris(2-aminoethyl)amine (TREN), ethylenediamine (EDA) and hexamethylenediamine (HMDA) in order to provide functional groups. • Functionalization of the calix[4]arene on the lower rim (diester). • Synthesis and Characterization of nanocomposites (SC-GA-TREN-Calix2, SC-GA-EDA-Calix2 and SC-GA-HMDA-Calix2) The present work studied the synthesis of nanocomposites calix[4]arene-modified-clay. The calix[4]arene diester was prepared and characterized. Purified clay was firstly silylated with APTES silane before grafting the glutaraldehyde. Then, tris(2-aminoethyl)amine, ethylenediamine or hexamethylenediamine were grafted. The structures of the silylated and modified clays were characterized by various techniques. The calix[4]arene diester was grafted onto modified clays. All data demonstrated the successful grafting of calix[4]arene, and indicated that in the case of the nanocomposites with aliphatic amines, the calixarene was grafted by a single ester function, whereas by two ester functions in the case of the nanocomposite with branched amine. [ABSTRACT FROM AUTHOR]

Amine-functionalized, silver-exchanged zeolite NaY (ZSA) were prepared with three different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.20 and 0.40 M) and four different concentrations of silver ions (25%, 50%, 100% and 200% from zeolite cation exchange capacity (CEC)). The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), surface area analysis, thermogravimetric analysis (TGA) and zeta potential (ZP) analysis. The FTIR results indicated that the zeolite was functionalized by APTES and that the intensity of the peaks corresponding to APTES increased as the concentration of APTES used was increased. The antibacterial activities of the silver-exchanged zeolite NaY (ZS) and ZSA were studied against Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538 using the disc diffusion technique (DDT) and minimum inhibitory concentration (MIC). The antibacterial activity of ZSA increased with the increase in APTES on ZS, and E. coli was more susceptible towards the sample compared to S. aureus. The FESEM micrographs of the bacteria after contact with the ZSA suggested different mechanisms of bacterial death for these two bacteria due to exposure to the studied sample. The functionalization of ZS with APTES improved the antibacterial activity of the silver-zeolite, depending on the concentration of silver ions and APTES used during modification. [ABSTRACT FROM AUTHOR]

The CO2 adsorption capacity of different functionalized mesoporous silicas of the SBA-15 type was investigated and the influence of textural properties and the effect of the silicon source on the CO2 uptake studied. Several adsorbents based on SBA-15 were synthesized using sodium silicate as silicon source, replacing the commonly used tetraethyl orthosilicate (TEOS). Thus, we synthesized three couples of supports, two at room temperature (RT, RT-F), two hydrothermal (HT, HT-F) and two hydrothermal with addition of swelling agent (1,3,5-triisopropylbenzene) (TiPB, TiPB-F). Within each couple, one of the materials was synthesized with ammonium fluoride (NH4F). The supports were functionalized via grafting 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethylenimine ethylenediamine branched (PEI). The adsorption behavior of the pure materials was described well by the Langmuir model, whereas for the amine-silicas, a Dualsite Langmuir model was applied, which allowed us to qualify and quantify two different adsorption sites. Among the materials synthesized, only the SBA-15 synthesized at room temperatures (RT) improved its properties as an adsorbent with the addition of fluoride when the silicas were functionalized with APTES. The most promising result was the TiPB-F/50PEI silica which at 75 °C and 1 bar CO2 captured 2.21 mmol/g. [ABSTRACT FROM AUTHOR]

A two-component waterborne polyurethane (2K-WPU) was obtained by the reaction between a hydroxyl-component waterborne polyurethane and a hydrophilically modified polyisocyanate. A hydroxyl-component waterborne polyurethane with a cross-link structure of Si-O-Si groups was synthesized by means of 3-aminopropyltriethoxysilane (APTES) and trimethylolpropane end-capping concurrently. Mean particle size and viscosity of the hydroxyl-component WPU mini-emulsions were examined by a laser particle analyzer and a Brookfield viscometer. Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were utilized to analyze the chemical structure of 2K-WPU films. The influence of APTES content on thermal stability, mechanical properties, and solvent resistance of 2K-WPU films was also investigated by thermogravimetric analysis (TGA), a universal testing machine, and an immersion test under three kinds of solvent (ethanol, acetone, and dichloromethane) for 24 h, respectively. The results show that 2K-WPU films containing APTES have excellent thermal stability, tensile strength, and breaking elongation. Additionally, these films possess the strongest resistance to ethanol, as well as resistance to acetone and dichloromethane to a certain extent at the APTES content of 4 wt.%. [ABSTRACT FROM AUTHOR]

Diagrammatic representation of 3-aminopropyltriethoxysilane and glutaraldehyde functionalization of halloysite nanoclay for the immobilization of endoinulinase. [Display omitted] • Endoinulinase was successfully immobilized onto hetero-modified halloysite nanoclay. • APTES and glutaraldehyde was found an effective crosslinking agents for immobilization. • Immobilization shown a drastic change in kinetic characteristics of endoinulinase. • Enhancement in the t 1/2 and D-value of immobilized endoinulinase was observed. • Immobilized biocatalyst shown a good operational stability for FOSs production. Present investigation describes immobilization efficiency of endoinulinase onto hetero-functionalized halloysite nanoclay using 3-aminopropyltriethoxysilane and glutaraldehyde as crosslinkers. Under optimal conditions (APTES 0.75%, sonication time 2.25 h, glutaraldehyde 0.75%, activation-time 65 min, immobilized endoinulinase load 60 IU and coupling-time 1 h), maximum yield in enzyme activity (70.65%) and immobilization (89.61%) was obtained. Developed immobilized biocatalyst shown maximum activity at 65 °C and pH 5.0 with wide range thermal (50–80 °C) and pH (4.0–9.0) stability. Increase in half-life (28.70-fold) of immobilized endoinulinase was observed as compared to free enzyme. An enhanced K m and reduced V max of endoinulinase for inulin was recorded after immobilization. Maximum FOSs production 98.42% was obtained, under optimized conditions (inulin 10%; immobilized endoinulinase load 85 IU; hydrolysis-time 10 h and agitation rate 130 rpm) containing kestose (36.26%), nystose (27.02%), fructofuranosylnystose (9.98%) and FOSs DP 5–9 (25.15%). Developed immobilized biocatalyst exhibited a splendid operational stability for 18 batch cycles. [ABSTRACT FROM AUTHOR]

In this work, we demonstrated a facile approach for preparation of Au popcorns by using 3-aminopropyltriethoxysilane (APTES) as ligand. It was identified that APTES monomers acted as ligand to tune activity of the gold precursor and direct the preferential growth of (111) plane of face-centered cubic (fcc) Au, resulting in the formation of Au particles popcorn-like in shape via random attachment fashion. Attributed to the existence of APTES layer on their surface, the resulting Au popcorns presented excellent stability and improved peroxidase-like activity, making them qualified as probe for colorimetric and surface-enhanced Raman scattering (SERS) dual detection of cysteine. [Display omitted] • Au popcorns were prepared by using 3-aminopropyltriethoxysilane (APTES) as ligand. • The Au popcorns presented excellent stability due to protection effect of APTES. • Improved peroxidase-like activity of the Au popcorns made them qualified as dual probe for detection of cysteine. [ABSTRACT FROM AUTHOR]

Chemical Mechanical Polishing (CMP) is a widely used surface treatment process in integrated circuit manufacturing for global planarization of the surface layers of various materials. The CMP slurry is regarded as one of the key determinants of planarization performance, considering the synergistic effect of its abrasive and other chemical components. As the component size is decreased to the molecular or even atomic scale, ways to achieve a high material removal rate of the SiO 2 dielectric layer while maintaining high surface topography quality have become a challenge for the integrated circuit manufacturing industry. In this work, the synergistic effect of aminosilane and K 2 CO 3 in the SiO 2 CMP process was identified. A material removal rate of 248 nm/min and surface roughness of 0.374 nm was achieved under a pH of 11, SiO 2 abrasive of 12 wt%, K 2 CO 3 concentration of 0.12 M, and 3-aminopropyltriethoxysilane (APTES) concentration of 60 ppm. Through X-ray photoelectron spectroscopy (XPS), it was found that APTES can be adsorbed on the surface of SiO 2 film through chemical bonding. Further, it was proved by fourier infrared spectroscopy (FTIR) that APTES could be combined with abrasive particles and coated on the surface of abrasive to realize the modification. The changes in particle size and zeta potential of the slurry were measured with a laser particle size analyzer. The studies suggested that under the influence of K 2 CO 3 , the hydration reaction on the SiO 2 surface was intensified, the chemical bonding between APTES and the silanol (Si–OH) dangling bond on both surface of abrasive and SiO 2 film was established, which enhanced the chemical reaction on the wafer surface. Finally, a material removal model of SiO 2 , characterized by the synergistic effect of APTES and K 2 CO 3 was proposed based on the study. [ABSTRACT FROM AUTHOR]

Cocoa pod husk (CPH) is a waste material from cocoa industry. This work describes the development of biocomposites from polypropylene and cocoa pod husk. 3-aminopropyltriethoxysilane (3-APE) is used as coupling agent in filler treatment of CPH. The treated CPH with 3-APE had raised the stabilization torque of PP/CPH biocomposites. The results of tensile test and scanning electron microscope (SEM) indicated that 3-APE given coupling effect on PP/ CPH biocomposites. The presence of covalent bonds between CPH and 3-APE was confirmed by Fourier transmission infra-red (FTIR) analysis, while the improvement of thermal stability and crystallization were evidenced by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Three ultrathin films consisting of dendrimer self-assembled monolayer (SAM), silica particle/dendrimer SAM and silica particles have been prepared on glass surface to develop solvo-affinity and surface roughness and to elucidate the anti-fingerprint effect. The solvo-affinity and surface roughness of the coated films on glass surface were characterized by contact angle measurement and atomic force microscope. The results showed that the fabrication of dendrimer SAM on glass revealed the significantly high hydrophobicity. The loading of silica particles also enhanced hydrophobicity. Thus, the roughness of the surface was enhanced, suggesting the meaningful relation of hydrophobicity and roughness. However, the probable relation of anti-fingerprint property with solvo-affinity and surface roughness was not necessarily found, although the highest anti-fingerprint property was observed for a SAM of 3-aminopropyltriethoxysilane on glass which displayed medium hydrophobicity. [ABSTRACT FROM AUTHOR]

Highlights: [•] The incorporation of APTES improved mechanical properties of the coating films. [•] The incorporation of APTES improved the water and toluene resistance. [•] The 3H pencil could not mar the coatings surface. [•] The coatings showed high transparence. [ABSTRACT FROM AUTHOR]

Abstract: Paper based colorimetric biosensing platform utilizing cross-linked siloxane 3-aminopropyltriethoxysilane (APTMS) as probe was developed for the detection of a broad range of targets including H2O2, glucose and protein biomarker. APTMS was extensively used for the modification of filter papers to develop paper based analytical devices. We discovered when APTMS was cross-linked with glutaraldehyde (GA), the resulting complex (APTMS–GA) displays brick-red color, and a visual color change was observed when the complex reacted with H2O2. By integrating the APTMS–GA complex with filter paper, the modified paper enables quantitative detection of H2O2 through the monitoring of the color intensity change of the paper via software Image J. Then, with the immobilization of glucose oxidase (GOx) onto the modified paper, glucose can be detected through the detection of enzymatically generated H2O2. For protein biomarker prostate specific antigen (PSA) assay, we immobilized capture, not captured anti-PSA antibody (Ab1) onto the paper surface and using GOx modified gold nanorod (GNR) as detection anti-PSA antibody (Ab2) label. The detection of PSA was also achieved via the liberated H2O2 when the GOx label reacted with glucose. The results demonstrated the possibility of this paper based sensor for the detection of different analytes with wide linear range. The low cost and simplicity of this paper based sensor could be developed for “point-of-care” analysis and find wide application in different areas. [Copyright &y& Elsevier]

Abstract: Glass microfibers are commonly used as biomolecule adsorption media, as structural or disposable components of the optical biosensors. While any improvement in these components are appreciated, utilizing basic tools of traditional approaches may lead to original sensor opportunities as simple, functional designs that can be easily disseminated. Following this pursuit, surface modification of glass microfiber paper surface was performed by 3-aminopropyltriethoxysilane (APTES) and resulting improvement in the cell entrapment capacity could be observed visually, only after Gram staining. Gram staining offered rapid validation of enhanced binding on the glass surface. The same APTES-modified samples were also tested for binding of complementary DNA sequences and the results were less straightforward due to the necessity of DNA visualization by using a fluorescent stain, YOYO-1. Accordingly, when there were no surface modification, DNA and YOYO-1 adsorbed readily on the glass microfiber filter paper, and prolonged the interaction between DNA and YOYO-1. YOYO-1 adsorption on glass could be recognized from the color profile of YOYO-1 emission. This phenomenon can be used to examine suitability of APTES coverage on glass surfaces since YOYO-1 emission can be distinguished by its glass adsorbed versus DNA-bound forms. Aptness of surface coverage is vital to biosensor studies in the sense that it is preceding the forthcoming surface modifications and its precision is imperative for attaining the anticipated interaction kinetics of the surface-immobilized species. The proposed testing scheme offered in this study secures the work, which is aimed to be carried out utilizing such sensing systems and device components. [Copyright &y& Elsevier]

The modification of montmorillonite clay mineral (Mt) was performed using the 3-aminopropyltriethoxysilane (γ-APS) silylation agent in different synthesis solutions. The modified products (S-Mt) were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The XRD demonstrated that silane was intercalated in the interlayer space of Mt due to the increase in basal spacing. The basal spacing shown by some S-Mts suggests the presence of a double layer of aminopropyl molecules in the interlayer space of the clay mineral modified in water and in a hydroalcoholic media at both synthesis temperatures (50°C and 80°C). The TGA revealed the presence of peaks in the range of 200°C to 600°C due to the presence of adsorbed silanes, intercalated silanes and silanes chemically bonded between the clay mineral layers and/or the edges. Evidence showed that the presence of water in dispersant is essential for intercalation of the silane in the interlayer space of the Mt such that the S-MMTwater, S-MtE/A(50) e S-MtE/A(80) showed higher amount of silane and higher basal spacing in its structure. Qualitative evidence of the presence of γ-APS in the modified clay minerals was obtained by FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: Imine-modified silicas were synthesized by the reaction of the essential oil of Eucalyptus citriodora, 3-aminopropyltriethoxysilane and tetraethylorthosilicate by different methods. The imine supported on silica was characterized by FT-IR-spectroscopy using the attenuated total reflection (ATR) technique, the Brunauer–Emmett–Teller (BET) method and thermogravimetric analysis (TGA). These silicas have shown a large amount of organic matter incorporated on the surface, which affects their textural properties. The hydrolysis reaction of the imine-modified silica leads to the formation of products different from those expected. [Copyright &y& Elsevier]

Highlights: [•] A multi-step approach was developed for the efficient doping of amino-reactive dyes into silica particles. [•] This approach included surface modification and then covalent coupling of the dyes on the particle surface. [•] Doping efficiency of typical amino-reactive dye such as fluorescein isothiocyanate was as high as 91%. [•] The dye doped silica particles showed bright luminescence and excellent anti-leaking ability. [Copyright &y& Elsevier]

Abstract: Immobilization of chromium complexes on modified silica support was achieved via two different synthetic routes using 3-aminopropyl triethoxysilane (APTS) as a linking group. The FTIR spectra, elemental and solid-state NMR analyses demonstrated incorporation of amine functional groups on the surface of the APTS-functionalized silica support, which was further confirmed by 29Si solid-state CP MAS NMR spectroscopy. Oxidation of cyclohexene was carried out over the chromium complex supported on organically modified silica using H2O2 as an oxidant under various conditions and different atmospheres viz. oxygen, nitrogen and air. The supported catalysts exhibited excellent activity (>94%) after 6h reaction time under O2 atmosphere using THF as solvent. The catalysts showed high chemoselectivity towards formation 2-cyclohexen-1-ol and 2-cyclohexen-1-one. Activity of the immobilized catalysts remains nearly the same after three consecutive cycles, suggesting the true heterogeneous nature of the catalyst. [Copyright &y& Elsevier]

This work presents the synthesis and use of surface-modified iron oxide nanoparticles for the covalent immobilization of Bacillus licheniformis γ-glutamyl transpeptidase (BlGGT). Magnetic nanoparticles were prepared by an alkaline solution of divalent and trivalent iron ions, and they were subsequently treated with 3-aminopropyltriethoxysilane (APES) to obtain the aminosilane-coated nanoparticles. The functional group on the particle surface and the amino group of BlGGT was then cross-linked using glutaraldehyde as the coupling reagent. The loading capacity of the prepared nanoparticles for BlGGT was 34.2 mg/g support, corresponding to 52.4% recovery of the initial activity. Monographs of transmission electron microscopy revealed that the synthesized nanoparticles had a mean diameter of 15.1 ± 3.7 nm, and the covalent cross-linking of the enzyme did not significantly change their particle size. Fourier transform infrared spectroscopy confirmed the immobilization of BlGGT on the magnetic nanoparticles. The chemical and kinetic behaviors of immobilized BlGGT are mostly consistent with those of the free enzyme. The immobilized enzyme could be recycled ten times with 36.2% retention of the initial activity and had a comparable stability respective to free enzyme during the storage period of 30 days. Collectively, the straightforward synthesis of aldehyde-functionalized nanoparticles and the efficiency of enzyme immobilization offer wide perspectives for the practical use of surface-bound BlGGT. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of the novel nanopore Ti surface and amine-terminated Ti surface on peri-implant bone formation and bone-implant bonding strength in a rabbit tibiae model. Characterization of the modified Ti surface, such as root-mean square roughness, contact angle, and surface energy was evaluated using scanning electron microscopy, atomic force microscopy, and a Contact Angle Measurement System, respectively. The results from alkali treatment indicated that an interpenetrating dimensional porosity surface had been formed, whose morphology was similar to the amine-terminated surface of self-assembled monolayers after alkali treatment. The micro-CT demonstrated that the amine-terminated surface had higher bone volume ratio and higher mean trabecular thickness after 4 weeks of implantation. The push-out test and histological examination showed no significant differences in the maximal force and bone-implant contact between the terminated surface and alkali-treated surface. These novel dimensional nanoporous structures can significantly improve the initial stabilization and the osseointegration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3428-3435, 2012. [ABSTRACT FROM AUTHOR]

Designing biointerfaces with enhanced biomolecule binding abilities, along with their distribution and presentation on the surface, largely requires control over underlying surface chemistries. In an effort to correlate experimental parameters to surface properties, ligand distribution and biomolecule binding, the influence of (3-aminopropyl)triethoxysilane (APTES) concentration (1, 2 and 4 vol%) and duration of the silanization reaction (5–60 min) on the number of available - NH2 groups were determined and correlated with the amount of surface bound human immunoglobulin G (HIgG). Surfaces silanized with 2 vol% APTES for 30 min yielded a densely populated silane monolayer (1.0–1.2 nm) where the average molecular orientation was 38 ± 2° with respect to the surface normal. A surface density of - NH2 moieties of ∼1015/cm2 was obtained and was significantly higher compared to other conditions evaluated. The combined data from ellipsometry and atomic force microscopy (AFM) analyses supports our findings. Coupling of HIgG to surfaces silanized with 2 vol% APTES for 30 min yielded ∼1013 IgG/cm2, which was significantly higher than values obtained at 1 vol% APTES for 30 min. The distribution of immobilized HIgG was noted to be dense and uniform on surfaces silanized with 2 vol% APTES when visualized using Nanogold® antibody conjugates. This study highlights the critical role of the experimental parameters that impact the biomolecule immobilization process on functionalized surfaces. [Copyright &y& Elsevier]

Micron-scale hollow spheres were successfully constructed with silica nanoparticles by templating of polymer spheres. Subsequently, the use of 3-aminopropyltriethoxysilane (APTES) introduces carbon and oxygen defects in the silica nanoparticles resulting from calcination of the aminopropyl group. In this approach, the template of micron-scale polymer spheres was prepared from dispersion polymerization. Subsequent Stöber process results in the formation of a silica layer attached to the polymer sphere surfaces. After calcination, the obtained micron-scale hollow silica spheres were then studied on the relationship between the particle diameter and the surface morphology. The luminescence of hollow spheres was prepared through using APTES in Stöber process, and which of related the appearance of luminescence to the APTES concentration and calcination temperature. The results of this study can provide useful information for the structure of micron-scale hollow spheres and their application to luminescent materials. [ABSTRACT FROM AUTHOR]

Polymer/clay composites have several uses in fields such as engineering, agriculture, ceramics, surface coatings, absorbent materials, pharmaceuticals or catalysis. Polysaccharides, such as alginate and its acid derivatives, are biocompatible and biodegradable polymers, effective in the production of adsorbent systems, for encapsulation and controlled release of active ingredients such as drugs and fertilizers. In this work, alginate polysaccharide and alginic acid were used to form composites with laponite, both with the original clay or with clay previously functionalized with 3-aminopropyltriethoxysilane. The properties of the composites prepared from laponite or functionalized laponite and alginic acid or alginate were compared. The interaction of laponite with alginic acid leads to composites with strong disorder in the clay structure. In all cases, composites with high contents of polysaccharides, with good thermal and mechanical properties, are obtained. Laponite-derived composites showed high adsorption capability for Cr(III) and methylene blue from aqueous medium. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Esterification of oleic acid with methanol was investigated using tungstophosphoric acid (H3PW12O40) immobilized on the 3-aminopropyltriethoxysilane (H2N(CH2)3Si(OC2H5)3) functionalized palygorskite. Among different loading catalysts, 15% (w/w) H3PW12O40 immobilized onto functionalized palygorskite showed stable and substantially high activity with about 90% oleic acid conversion. Immobilized catalysts were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and temperature programmed desorption of NH3 for their surface element compositions and chemical states, crystallization, and acid strength, respectively. Characterization results indicated that H3PW12O40 was chemically and uniformly dispersed on modified palygorskite. [ABSTRACT FROM PUBLISHER]

Hydroxyapatite whiskers (HAW) with a maximum aspect ratio of 20 were employed to improve the toughness of poly(L-lactide-co-glycolide) (PLGA). 3-Aminopropyltriethoxysilane (AMEO) was grafted on the surface of the hydroxyapatite whiskers (g-HAW) to improve its wetting in the PLGA matrix. Composites based on HAW, g-HAW, and PLGA were prepared. The structure and properties of the composites were subsequently investigated by powder X-ray diffraction (XRD), scanning electron microscopy, differential scanning calorimetry, and tensile testing. The g-HAW were distributed homogenously in the PLGA matrix because of improved wetting of g-HAW while the HAW were aggregated. The stronger interfacial bonding also gave rise to improved mechanical properties of the g-HAW/PLGA composites. The HAW/PLGA and g-HAW/PLGA composites failed in a tough manner with intensive plastic deformation. The g-HAW/PLGA composite (5 wt% g-HAW) failed at a maximum elongation of 366%, although the tensile strength dropped slightly. The g-HAW/PLGA composite (1 wt% g-HAW) maintained the initial tensile strength of neat PLGA but failed at an equally high elongation of 347%, whereas PLGA failed at an elongation of 11%. [ABSTRACT FROM PUBLISHER]

Abstract: A sequential layer formation chemistry is demonstrated for the functionalization of silicon carbide (SiC) appropriate to biosensing applications. (0001) 4H–SiC was functionalized with 3-aminopropyltriethoxysilane (APTES) and subsequently biotinylated for the selective immobilization of streptavidin. Atomic force microscopy, X-ray photoelectron spectroscopy, ellipsometry, fluorescence microscopy, and contact angle measurements were utilized to determine the structure, thickness, wettability, and reactivity of the resulting surface after each functionalization step. Optimization of the APTES layer was found to be critical to the success of the subsequent steps; multilayer, polymeric films resulted in irreproducible behavior. It was shown that there was significant non-specific (electrostatic) binding of streptavidin to APTES functionalized SiC, thus revealing the importance of a uniform biotinylation step prior to streptavidin attachment. The experimental results demonstrate that the APTES functionalized and biotinylated SiC surface has the potential to be employed as a biosensing platform for the selective detection of streptavidin molecules. [Copyright &y& Elsevier]

The effects of the filler content and the coupling agent 3-aminopropyltriethoxysilane (3-APE) on the mechanical properties, thermal properties, and morphologies of polylactic acid (PLA)/coconut shell powder (CSP) biocomposites were investigated. It was found that increasing the CSP content decreased the tensile strengths and elongations at break of the PLA/CSP biocomposites. However, incorporating CSP increased their modulus of elasticity. The tensile strengths and modulus of elasticity of the PLA/CSP biocomposites were enhanced by the presence of 3-APE, which can be attributed to a stronger filler-matrix interaction. The thermal stabilities of the biocomposites increased with the filler content, and they were enhanced by 3-APE treatment. Meanwhile, the presence of CSP increased the glass transition temperatures ( T) and crystallinities ( X) of the PLA/CSP biocomposites at a filler content of 30 php. After 3-APE treatment, T and X of the PLA/CSP biocomposites increased due to enhanced interfacial bonding. The presence of a peak crystallization temperature ( T) for the PLA/CSP biocomposites indicated that the CSP has a nucleating effect. The melting temperatures ( T) and the T values of the biocomposites were not significantly affected by the filler content and 3-APE. PLA/CSP biocomposites that had been treated with 3-APE presented the strongest filler-matrix interaction, as confirmed by SEM. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a CdSe/ZnS quantum dot (QD)-based immunosensor using a simple optical system for human serum albumin (HSA) detection is developed. Monoclonal anti-HSA (AHSA) immobilized on 3-aminopropyltriethoxysilane (APTES)-modified glass was used to capture HSA specifically. Bovine serum albumin (BSA) was used to block non-specific sites. The solution, containing AHSA–QD complex prepared by mixing biotinylated polyclonal anti-HSA and streptavidin coated QD, was used to conjugate with the HSA molecules captured on AHSA/BSA/APTES-modified glass for the modification of HSA with QD. A simple optical system, comprising a diode laser (405nm), an optical lens, a 515-nm-long pass filter, and an Si-photodiode, was used to detect fluorescence and convert it to photocurrent. The current intensity was determined by the amount of QD specifically conjugated with HSA, and was therefore HSA-concentration-dependent and could be used to quantify HSA concentration. The detection limit of the pure QD solution was ∼3.5×10−12 M, and the detection limit for the CdSe/ZnS QD-based immunosensor developed in this study was approximately 3.2×10−5 mg/ml. This small optical biosensing system shows considerable potential for future applications of on-chip liver-function detection. [Copyright &y& Elsevier]

Abstract: The residual proteins in commercially available chitosan products potentially induce immunological responses, thus compromising their clinical usage. Conventional deproteinization processes use diluted base and heat. However this heterogeneous hydrolysis is inefficient. In the present study, pepsin was selected and immobilized with tetramethoxysilane (TMOS) and 3-aminopropyltriethoxysilane (APTES). The immobilized pepsin was utilized in an alternative approach for the purification of chitosan. Optimum deproteinization was carried out at pH 4.5 and 45°C. Amino acid analysis proved a removal of 53.8–80.4% protein in chitosan after 160min incubation, which was more efficient than conventional sodium hydroxide deproteinization. When chitosan was deproteinizated by immobilized pepsin, its molecular weight decreased, but in a much milder manner than the free pepsin. The study revealed that immobilized pepsin was an efficient method for deproteinizing chitosan. [Copyright &y& Elsevier]

Abstract: The present paper describes the influence of the chemical structure of two aminoalkoxysilanes: 3-aminopropyltriethoxysilane (APTS) and N-(3-(trimethoxysilyl)-propyl)-ethylenediamine (TSPEN) on the morphology of thin layer hybrid films with phosphotungstic acid (HPW), a Keggin heteropolyanion. X-ray photoelectron spectroscopy analyses indicated that both silane films showed protonated amine species interacting with the heteropolyanion by electrostatic forces as well as the presence of secondary carbamate anions. The hybrid films have different surface morphology according to atomic force microscopy analyses. The hybrid film with TSPEN forms flatter surfaces than the hybrid film with APTS. This effect is ascribed to higher flexibility and chelating ability of the TSPEN on adsorbed molecules. Ultrasonication effect on surface morphology of the hybrid film with APTS plays a fundamental role on surface roughness delivering enough energy to promote surface diffusion of the HPW heteropolyanions. This diffusion results in agglomerate formation, which corroborates with the assumption of electrostatic bonding between the HPW heteropolyanions and the protonated amine surface. These hybrid films could be used for electrochemical sensor design or to build photochromic and electrochromic multilayers. [Copyright &y& Elsevier]

In this work, 3-aminopropyltriethoxysilane modified FeO nanoparticles (ATPS-FeO) were used to modify glassy carbon electrode for aminopyrine determination. ATPS-FeO showed obviously catalytic activity and adsorptivity towards aminopyrine oxidation proven by the increased oxidation peak current and the decreased oxidation peak potential. The best analytical response was obtained by immobilizing 8 μL 3 mg/mL APTS-FeO dispersion with an accumulation time of 200 s at −0.2 V in 0.1 M phosphate buffer solution (pH 9.0). The oxidation peak current of aminopyrine showed linear relationship with its concentration in the range from 0.5 to 100 and 100 to 1600 μM. The detection limit was 0.1 μM (S/N = 3). The proposed method showed satisfactory repeatability and anti-interference ability. The fabricated electrode was successfully applied to determine aminopyrine in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Abstract: A simple, elegant method for the formation of a continuous stationary phase gradient for use in chromatographic separations is described. Its applicability to separation science is demonstrated using thin-layer chromatography as a test case. Gradient stationary phases were formed on activated High Performance Thin-Layer Chromatography (HP-TLC) plates using a newly developed methodology termed “controlled rate infusion”. Specifically, the SiOH groups on the activated HP-TLC plates were reacted with 3-aminopropyltriethoxysilane (APTEOS) in a time dependent fashion by using a programmable syringe pump to control the rate of APTEOS infusion into the deposition reservoir. The shape (profile) of the gradient was controlled by the rate of infusion and imaged by taking advantage of the concentration-dependent color formation reaction between amine groups and ninhydrin. The advantages of such gradients in optimizing the retention and separation of various components in different mixtures were illustrated using mixtures of (1) four weak acids and bases and (2) three widely used over-the-counter drugs. The separation of the individual components on the gradient stationary phase was clearly improved relative to those on either traditional normal-phase TLC plates or uniformly amine-modified TLC plates. Precise control over component retention and separation was also demonstrated by strategically modifying the steepness of the gradient. [Copyright &y& Elsevier]

Abstract: In this study, electrical impedimetric biosensors composed of Au-electrodes were fabricated for the quantitative detection of human serum albumin (HSA), an essential biomarker of liver function. The Au-electrodes were fabricated via a single-step photolithography process, and can be easily integrated in biochips for assessing liver function in the future. The glass sensing surface between two adjacent Au-electrodes was modified with 3-aminopropyltriethoxysilane (APTES) to improve the biocompatibility for its subsequent binding to anti-human serum albumin (AHSA). The sensing surface without AHSA binding was blocked using skim milk powders, preventing possible non-specific bonding HSA conjugation. Biosensors were used to measure HSA concentration for liver function detection. The impedance between two adjacent Au-electrodes of the biosensors applied with various HSA concentrations was directly measured, and quantified using an electrochemical impedance spectroscopy system under AC conditions. The results of plotting both values in log scales indicated the impedance increased linearly with HSA conjugation increase. The limit of HSA detection was about 2′10−4 mg/ml using the electrochemical impedimetric biosensor proposed in this work. This study demonstrates the feasibility of using electrochemical impedimetry as a bio-sensing mechanism to quantify human serum albumin concentration. The sensor proposed in this work also displays great potential for assessing liver function because of its simple detection mechanism, ease of biochip integration, and low cost. [Copyright &y& Elsevier]

In this paper, we report the γ-ray sterilization effects in pH-sensitive polysilicon wire (PSW) sensors using a mixture of 3-aminopropyltriethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs) as a sensing membrane. pH analyses showed that the γ-ray irradiation-induced sensitivity degradation of the PSW pH sensor covered with γ-APTES/silica NPs nanocomposite (γ-APTES+NPs) could be restored to a condition even better than prior to γ-ray irradiation by 40-min of post-sterilization room-temperature UV annealing. We found that the trapping charges caused by γ-ray sterilization primarily concentrated in the native oxide layer for the pH sensor covered with γ-APTES, but accumulated in the γ-APTES+NPs layer for the γ-APTES+NPs-covered sensor. It is believed that mixing the PDMS-treated silica NPs into γ-APTES provides many γ-APTES/SiO2 interfaces for the accumulation of trapping charges and for post-sterilization UV oxidation, thus restoring γ-ray-induced sensor degradation. The PDMS-treated silica NPs not only enhance the sensitivity of the pH-sensitive PSW sensors but are also able to withstand the two-step sterilization resulting from γ-ray and UV irradiations. This investigation suggests γ-ray irradiation could be used as a highly-efficient sterilization method for γ-APTES-based pH-sensitive biosensors. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the titanium plates, which were modified by NaOH alkali solution, were associated with 3-Aminopropyltriethoxysilane (APTES) films using self-assembled monolayers (SAMs). The surfaces of titanium before and after modification were characterized by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total refraction–Fourier transform infrared spectroscopy (ATR–FTIR). After bonding the APTES films on the modification titanium, the new peaks located around 1095cm−1 attributes to siloxane groups indicating that silane agent had been grafted onto the surface of the modification titanium substrate by SAMs. Following the deposition of APTES films on titanium, significant change were seen in the amounts of oxygen, silicon and carbon present on the titanium surface, which were consistent with the anticipated reaction steps. [Copyright &y& Elsevier]

Abstract: Aminopropylated nanosilica was prepared by a simple sol–gel process from tetraethyl orthosilicate (TEOS) and then it was functionalized with different amounts of 3-aminopropyltriethoxysilane (APS) under toluene reflux. The prepared solids were characterized by means of XRD, FT-IR, TGA–DTA, SEM–EDS, and TEM. Their textural properties were determined by adsorption–desorption isotherms of N2 at 77K. It was proved that the amount of APS used in the preparation process had a great influence on the physicochemical properties of the hybrid organic–inorganic solid materials. The materials were used as catalyst in the Claisen–Schmidt preparation of chalcones for the reaction of substituted acetophenones and benzaldehydes under solvent-free conditions. The result showed that the presence of a high amount of aminopropyl groups was important for a very good performance of the catalyst in the substrate conversion. Also, the influence of different groups in the aromatic ring of acetophenones and benzaldehydes was investigated. In all cases, coproduct formation was not observed; the catalysts were recovered and can be recycled twice without appreciable loss of reactivity. [Copyright &y& Elsevier]