Search results for "SURFACE MODIFICATION"
showing 10 items of 417 documents
Tetrazine Click Chemistry for the Modification of 1-Hydroxy-1,1-methylenebisphosphonic Acids: Towards Bio-orthogonal Functionalization of Gold Nanopa…
2016
Inverse electron demand Diels-Alder (iEDDA) was evaluated for the functionalization of gold nanoparticles. The reaction was first modelled with the free coating molecule 1-hydroxy-1,1-methylenebisphosphonate bearing an alkene functionality (HMBPene). A model tetrazine 3,6-dipyridin-2-yl-1,2,4,5-tetrazine (pyTz) was used, kinetic of the reaction was calculated and coupling products were analysed by NMR and HRMS. The reaction was then transposed at the nanoparticle surface. Gold nanoparticles bearing an alkene functionality were obtained using a one-pot methodology with HMBPene and the tetrazine click chemistry was evaluated at their surface using pyTz. The successful coupling was assessed by…
Hydrophobically Modified Halloysite Nanotubes as Reverse Micelles for Water-in-Oil Emulsion.
2015
An easy strategy to obtain inorganic reverse micelles based on halloysite nanotubes (HNTs) and alkyltrimethylammonium bromides has been developed. The selective modification of the HNTs external surface with cationic surfactants endows to generate tubular nanostructures with a hydrophobic shell and a hydrophilic cavity. The influence of the surfactants alkyl chain on the HNTs functionalization degree has been investigated. The dynamic behavior of the surfactant/HNT hybrids in solvents with variable polarity has been correlated to their affinity toward hydrophobic media explored through partition experiments. The water-in-oil emulsion is able to solubilize copper sulfate, proving the incorpo…
A two-step synthesis of new macrobicyclic aza-ligands starting from “trans”dioxocyclam as diprotected macrocycle
1997
Abstract A rapid and convenient synthesis of two small aza-cryptands containing a 1,4,8,11-tetraazacyclotetradecane backbone is reported. This strategy can be applied to the preparation of many other aza-cages by varying the nature of the cross linker. Moreover, the two remaining secondary amine sites may allow the functionalization of these ligands or their grafting on a polymer.
Towards Multifunctional Materials Incorporating Elastomers and Reversible Redox-Active Fragments
2014
This paper presents a novel and unique feature of metallacarboranes, consisting of the linkage of this redox electro-active site to a stretchable polymer. This is based on polyTHF, a known and applied material. This hybrid material has the two ends functionalized: one with the aforemen- tioned redox molecule and the other with a terminal OH group, both linked by a molecular spring. Moreover, the redox electro-active molecules can be synthesized with either cobalt (cobaltabisdicarbollide) or with iron (ferrabisdi- carbollide), species whose respective E1/2 value differs by almost 1 V. The polymerization mechanism, based on an in- termediate molecular crystal structure, is explained through a…
Redox-Responsive Block Copolymers: Poly(vinylferrocene)-b-poly(lactide) Diblock and Miktoarm Star Polymers and Their Behavior in Solution
2013
The synthesis of diblock and miktoarm star polymers containing poly(vinylferrocene) (PVFc) and poly(l-lactide) (PLA) blocks is introduced. End functionalization of PVFc was carried out via end capping of living carbanionic PVFc chains with benzyl glycidyl ether (BGE). By hydrogenolysis of the benzyl protecting group a dihydroxyl end-functionalized PVFc was obtained. Both monohydroxyl- and dihydroxyl-functionalized PVFcs have been utilized as macroinitiators for the subsequent polymerization of l-lactide via catalytic ring-opening polymerization. A series of block copolymers and AB2 miktoarm star polymers was synthesized with varied PLA chain lengths. All polymers were characterized in detai…
Noncovalent molecular imprinting: antibody-like molecular recognition in polymeric network materials
1997
Abstract Molecular imprinting techniques allow the preparation of polymeric receptors which bind small molecules with affinities and selectivities of the same order as those observed in the binding of antigens by antibodies. The molecular imprinting technology has now reached a stage where the commercial use of imprinted materials is being assessed, notably for separations requiring strong and selective binding of small molecules. This development is driven by the potential advantages of polymeric receptors over biological in terms of stability, capacity, cost and ease of preparation. In this short review the state of the art of noncovalent imprinting is summarised indicating a few areas in…
Separation studies of amino acids, proteins and enzymes on bonded 1,2-dihydroxy-, 1,2-hydroxylamino-and amino silica packings
1979
1,2-dihydroxy-3-propoxypropyl (HPPS), 1-amino-2-hydroxy-3-propoxypropyl (AHPS) and 1-aminoethyl-3-aminopropyl (AEAPS) silica were synthesized by means of both a surface modification procedure (I) and a bulk modification procedure (II). Method (I) gave a surface concentration, α, of functional groups of 2–3 μmole/m2, whereas method (II) gave values up to 5 μmole/m2. Retention times, peak asymmetries and plate heights of thiamine and ascorbic acid eluted with aqueous buffer solutions ranging from pH 5.3 to 9.2 gave only a±5% variation over periods of 12 hours and more. The recoveries of selected enzymes and proteines examined under static and dynamic conditions were between 60% and 100% depen…
Optical planar Bragg grating sensor for real-time detection of benzene, toluene and xylene in solvent vapour
2012
Abstract We report on an optical planar Bragg grating sensor functionalized by a comparatively simple method to detect substances such as benzene, toluene and xylene (BTX). The functionalization is performed by allyl substituted γ -cyclodextrin derivatives which are immobilized on the sensor surface by dip coating. Our results prove the capability of this functionalized sensor system to detect lowest concentrations of BTX in solvent vapour in real-time with a sensitivity of 3±0.4 pm/100 ppm for benzene, 8±1 pm/100 ppm for toluene and 32±1 pm/100 ppm for m-xylene. Taking into account the spectral resolution and repeatability of the interrogation system this corresponds to a minimum concentra…
Host-guest interactions for extracting antibiotics with a γ-cyclodextrin poly(glycidyl-co-ethylene dimethacrylate) hybrid sorbent
2021
Abstract A procedure for the solid-phase extraction of antibiotics (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and sparfloxacin) in water has been developed. The sorbent used is based on a poly(glycidyl-co-ethylene dimethacrylate) network, whose previously modified surface has been functionalized with γ-cyclodextrin through a click-chemistry reaction. The architecture of the material has been characterized by thermogravimetric analysis, N2 adsorption-desorption, Raman spectroscopy, confocal microscopy, and scanning electron microscopy, showing good capability to be used as a filler for extraction cartridges. The optimization of the extraction methodology shows good intra-day and inter…
Carbohydrate nanocarriers in biomedical applications: functionalization and construction
2015
The specific targeting of either tumor cells or immune cells in vivo by carefully designed and appropriately surface-functionalized nanocarriers may become an effective therapeutic treatment for a variety of diseases. Carbohydrates, which are prominent biomolecules, have shown their outstanding ability in balancing the biocompatibility, stability, biodegradability, and functionality of nanocarriers. The recent applications of sugar (mono/oligosaccharides and/or polysaccharides) for the development of nanomedicines are summarized in this review, including the application of carbohydrates for the surface-functionalization of various nanocarriers and for the construction of the nanocarrier its…