Search results for "acrylamide"
showing 10 items of 485 documents
The uptake of N-(2-hydroxypropyl)-methacrylamide based homo, random and block copolymers by human multi-drug resistant breast adenocarcinoma cells
2009
A series of well-defined, fluorescently labelled homopolymers, random and block copolymers based on N-(2-hydroxypropyl)-methacrylamide were prepared by reversible addition–fragmentation chain transfer polymerization (RAFT polymerization). The polydispersity indexes for all polymers were in the range of 1.2–1.3 and the number average of the molar mass (Mn) for each polymer was set to be in the range of 15–30 kDa. The cellular uptake of these polymers was investigated in the human multi-drug resistant breast adenocarcinoma cell line MCF7/ADR. The uptake greatly depended on the polymer molecular mass and structure. Specifically, smaller polymers (approx. 15 kDa) were taken up by the cells at m…
Experimental design approach in the synthesis of molecularly imprinted polymers specific for iprodione fungicide
2015
International audience; An experimental design (ED) approach was applied to study the weight of three factors in the synthesis of a molecularly imprinted polymer (MIP) specific for iprodione fungicide. The objective was to obtain a high specific polymer with the best performance of iprodione binding. Thirteen iprodione-imprinted polymers and 13 non-imprinted polymers (NIP) were synthesized according to ED having 3 influencing factors: the polymerization method, the crosslinker nature and the functional monomer type. For each factor, two levels were studied: bulk and precipitation polymerization for the first factor, trimethylolpropane trimethacrylate (TRIM) and ethylene glycol dimethacrylat…
Nanotube Friendly Poly(N-isopropylacrylamide).
2010
Poly(N-ispropylacrylamide) [PNIPAM] is a widely studied polymer for use in biological applications due to its lower critical solution temperature (LCST) being so close to the human body temperature. Unfortunately, attempts to combine carbon nanotubes (CNTs) with PNIPAM have been unsuccessful due to poor interactions between these two materials. In this work, a PNIPAM copolymer with 1 mol-% pyrene side group [p-PNIPAM] was used to produce a thermoresponsive polymer capable of stabilizing both single and multi-walled carbon nanotubes (MWNTs) in water. The presence of pyrene in the polymer chain lowers the LCST less than 4 °C and the interaction with nanotubes does not show any influence on LC…
Use of two-dimensional thin-layer chromatography for the components study of poly(adenosine diphosphate ribose)
1990
Two-dimensional thin-layer chromatography on cellulose plates has been used for separating and quantifying the three adenosine derivatives: AMP, phosphoribosyl AMP (PRAMP), and (PR)2AMP obtained by venom phosphodiesterase digestion of poly(ADP-ribose). In vitro synthesized polymer, up to 300 derivatives in length were studied. Some parameters of the complexity of poly(ADP-ribose) could be deduced from our results: (i) The first branching point appears in fragments of approximately 21 derivatives in length. (ii) The branching points are located at regular distances of approximately 41 derivatives from each other.
New Perspectives of HPMA-based Copolymers Derived by Post-Polymerization Modification
2014
Poly[N-(2-hydroxypropyl) methacrylamide] (HPMA) was one of the first polymers applied as polymer drug conjugate in the clinics. Since then many attempts have been made to expand the functionality of HPMA-based copolymers from advanced synthetic pathways to multiple biomedical applications. This Feature Article highlights multifunctional HPMA based copolymers prepared by controlled radical polymerization and subsequent post-polymerization modification of activated ester precursor polymers via aminolysis. This approach combines precise control of the polymer's microstructure (molecular weight, dispersity, block copolymer formation, end group functionalization) with an easy introduction of var…
RAFT-polymerized poly(hexafluoroisopropyl methacrylate)s as precursors for functional water-soluble polymers
2014
Post-polymerization modification of well-defined precursor polymers is a versatile tool to obtain multifunctional water-soluble polymers that cannot be synthesized by common polymerization techniques. For the first time, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate (HFIPMA) based homo and block copolymers were synthesized via RAFT polymerization to provide precise precursors for the post-polymerization modification of the 1,1,1,3,3,3-hexafluoroisopropyl ester side chains with water-soluble amines (methoxy tri(ethylene glycol) amine, 2-hydroxypropyl amine and 3-(dimethylamino)-1-propylamine). Sequential aminolysis using Oregon Green cadaverine first followed by 2-hydroxypropyl amine enables …
Oxidative oligomerization of cyclodextrin-complexed bifunctional phenols catalyzed by horseradish peroxidase in water
2000
The HRP-catalyzed oligomerization of hydrophobic bifunctional phenols in water was realized by the use of 2,6-di-O-methylated β-cyclodextrin. The molecular weights of the resulting oligomers were in the same region as they were reached by conventional HRP-catalyzed oligomerizations in water/dioxane-mixtures. The polymerizable moieties, maleimide and methacrylamide, were not affected during the oligomerization process, as proofed by NMR, MALDI-TOF and FT-IR measurements. It was therefore possible to get soluble functionalized oligomers, which were crosslinked via radical copolymerization with suitable components (styrene, MMA) or heating.
Controlled cleavage of KLH1 and KLH2 by the V8 protease from Staphylococcus aureus reassociation, electrophoretic and transmission electron microscop…
1999
The reassociation behaviour of protease V8-cleaved peptides from KLH1 and KLH2, the two hemocyanin isoforms from the giant keyhole limpet Megathura crenulata, has been studied by transmission electron microscopy of negatively stained specimens and SDS/PAGE. Reassociation of the complete mixture of protease cleavage products and of combinations of peptide fragments purified by HPLC was performed in the presence of 100 mm CaCl2 and 100 mm MgCl2 at pH 7.4, over a period of 1 to 4 weeks. The V8 protease splits KLH1 into peptide fragments containing the functional units abc, def, defg, defgh, g and h. This mixture of peptide fragments reassociated to form helical tubular polymers, with a diamete…
Two proteases from nuclei of rat testis cells. I. Isolation
1987
Abstract Two proteases, assayed with fluorogenic peptides and tentatively designated Rc and Kc, have been isolated from nuclei of rat testis cells by differential extraction with acetic acid, removal of some proteins at pH 4.5, and polyacrylamide gel electrophoresis followed by electroblotting onto nitrocellulose paper. Protease R hydrolyzes t‐Butyl‐oxycarbonyl‐Val‐Pro‐Arg‐7‐amino‐4‐methyl‐coumarin and other peptides in which arginine is joined to 7‐amino‐4‐methyl‐coumarin by amide linkage. Protease Kc has a preference for peptides terminating in lysine‐7‐amino‐4‐methylcoumarin amide. Neither of these proteases is active against Glu‐Phe‐7‐amino‐4‐methyl‐coumarin amide or Carbobenzoxy‐Arg‐7‐…
Biocompatible Poly(N-isopropylacrylamide)-halloysite Nanotubes for Thermoresponsive Curcumin Release
2015
The grafting of poly(N-isopropylacrylamide) (PNIPAAM) onto the halloysite external surface is proposed in order to obtain a novel thermoresponsive drug carrier for curcumin delivery. The new nanomaterial is characterized by means of FT-IR spectroscopy, thermogravimetric analysis, and SEM investigations. A high density of polymer chain was achieved at the nanoparticle surface. The PNIPAAM dehydration phenomenon was observed in water above 32 °C that is nearly coincident with the lower critical solution temperature for the polymer. The colloidal stability as well as the wettability of the obtained nanomaterial may be triggered by temperature stimuli. In vitro tests simulating the gastro-intes…