Search results for "SURFACE MODIFICATION"
showing 10 items of 417 documents
Design and evaluation of sensory systems based on amphiphilic anthraquinones molecular receptors
2015
A new paradigm is described that allows one to create different types of sensors: from highly sensitive ones to practical household devices. Our approach relies on modular molecular receptors incorporating an intensely-colored aminoanthraquinone signaling unit equipped with both hydrophilic and hydrophobic modules, the number and size of which being configured in accordance with the targeted analyte and the sought detection method. An important advantage is the compliance with some principles of green chemistry, avoiding the use of toxic organic solvents. The proper functionalization of the anthraquinone scaffold afforded water-soluble chromoinophores capable of quantifying selectively Hg2+…
Mössbauer Spectroscopic Study and Magnetic Investigation of Iron(III) Complexes on a DendrimericBasis
2014
The functionalization of the molecular surface of various dendrimer generations with a phosphorous core and external amine groups is obtained by converting those amine groups into the corresponding imines of salicylaldehyde creating multiple coordination sites for the iron atoms. Treatment with iron(III) chloride yields multinuclear iron(III) complexes on a dendrimeric basis.The obtained multinuclear molecular systems exhibit extremely high total spin values. The influence of the generation growth on this type of coordination compounds is investigated by Mossbauer spectroscopy and SQUID magnetometry.
Light induced charging of polymer functionalized nanorods.
2010
ZnO nanorods were functionalized with new block copolymers containing a hole transporting moiety in one block and a dye and an anchor system in the second block. After functionalization, the ZnO nanorods are well dispersible in organic media and the fluorescence of the dye is quenched. Kelvin probe force microscopy was used to measure changes in electrical potential between the ZnO nanorod and the polymeric corona. Upon light irradiation, potential changes on the order of some tens of millivolts were observed on individual structures. This effect is attributed to light-induced charge separation between the ZnO nanorod and its hole transporting polymeric corona.
In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration
2012
A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…
Covalently bonded layer-by-layer assembly of multifunctional thin films based on activated esters.
2009
We demonstrate that chemically stable, multifunctional polymer thin films can be obtained using the layer-by-layer (LbL) deposition based on covalent bonds between adsorbing chains. Poly(pentafluorophenyl-4-vinylbenzoate) (P1) or poly(pentafluorophenylacrylate) (P2) polymers were assembled with poly(allyl amine) (PAAm) to yield LbL multilayer films through amide bond formation by the reaction between activated esters of P1 or P2 and amine groups in PAAm, which was quantitatively monitored by Fourier transform infrared spectroscopy (FT-IR). It was found that the difference in the solubility of P1 and P2 against ethanol, which was used as the solvent for PAAm, during the LbL deposition yields…
Semiconductor Nanocrystals with Multifunctional Polymer Ligands
2002
In this letter, we describe the preparation of a versatile polymer ligand, which can be attached to CdSe/ZnS semiconductor nanocrystals via a phase transfer reaction. The ligand is based on a chain of reactive esters, which can, in principle, be substituted by any compound containing amino-functionalities. The polymer/nanocrystal complexes are characterized in terms of structure and photostability.
Polymeric monolayers and liposomes as models for biomembranes. How to bridge the gap between polymer science and membrane biology?
1984
This contribution deals with the stabilization of membrane model systems, especially vesicles. The desired further biological functionalization of these stabilized polymeric membranes is possible via the incorporation of proteins. Addition of natural lipids to polymerizable membranes and degradation of the unpolymerized component after polymerization allows selective opening of otherwise stable compartments. Finally, first attempts are made to combine biological properties of natural cells and the durability of polymerized membranes via fusion of synthetic vesicles with natural cells.
A bio-orthogonal functionalization strategy for site-specific coupling of antibodies on vesicle surfaces after self-assembly
2019
Attaching targeting ligands on the surface of self-assembled drug delivery systems is the key request for a controlled transport of the drug to a desired location. Most commonly, the amphiphilic molecules (blockcopolymers, lipids etc.) are therefore pre-functionalized before the self-assembly takes place. However, this strategy cannot be applied, if it interferes with the self-assembly process, if the introduced functional groups react with loaded cargo or if natural carriers like extracellular vesicles should be functionalized. Here, we present the site-specific coupling of antibodies to the surface of amino group-terminated liposomes via bio-orthogonal copper-free click chemistry after li…
The surface modification of polymers to modulate endothelial cell growth
1996
The effect of nitrogen ion implantation or ion-assisted film deposition on the growth of human endothelial cells in vitro on a substrate has been studied. It was shown that the largest change occurs when TiO2 films were reactively sputtered onto the substrates, while the most passive surface was reactively sputtered SiO2. SEM pictures of the cells adhering to the various treated surfaces show that the cells were healthy. Future studies on the effect of alloy films and their oxides and nitrides are proposed.
Amino-functional polyethers: versatile, stimuli-responsive polymers
2020
Due to the increasing demand for “smart” materials and systems e.g. for actuators, microvalves, but also for drug delivery, electrooptical devices and many other applications, multi-stimuli responsive materials such as amino-functional polymers are attracting increasing attention in recent years. The hydrophilic character and excellent biocompatibility of the polyether backbone, in combination with multi-stimuli responsive amine moieties, offer intriguing opportunities for a wide range of applications, such as bioconjugation, stimuli-responsive drug delivery and surface modification. Furthermore, the controlled introduction of amino-functionalities at the polyether backbone via copolymeriza…