6974-31-8Relevant academic research and scientific papers
Multivalent interaction and selectivities in selectin binding of functionalized gold colloids decorated with carbohydrate mimetics
Roskamp, Meike,Enders, Sven,Pfrengle, Fabian,Yekta, Shahla,Dekaris, Vjekoslav,Dernedde, Jens,Reissig, Hans-Ulrich,Schlecht, Sabine
, p. 7448 - 7456 (2011)
Colloidal gold particles with functionalized organic shells were applied as novel selectin binders. The ligand shell was terminated with different monocyclic carbohydrate mimetics as simplified analogs of the sLex unit found in biological selectin ligands. The multivalent presentation of the sulfated selectin binding epitopes on the gold particles led to extremely high binding affinities towards L- and P-selectin and IC50 values in the subnanomolar range. Depending on the ring size of the sulfated carbohydrate mimetic, its substitution pattern and its configuration, different selectivities for either L-selectin or P-selectin were obtained. These selectivities were not found for gold particles with simple acyclic sulfated alcohols, diols and triols in the ligand shell. In addition, the influence of the particle size and the thickness of the hydrophobic organic shell were systematically investigated.
Effects of multivalent histamine supported on gold nanoparticles: activation of histamine receptors by derivatized histamine at subnanomolar concentrations
Gasiorek, Friederike,Pouokam, Ervice,Diener, Martin,Schlecht, Sabine,Wickleder, Mathias S.
, p. 9984 - 9992 (2015)
Colloidal gold nanoparticles with a functionalized ligand shell were synthesized and used as new histamine receptor agonists. Mercaptoundecanoic acid moieties were attached to the surface of the nanoparticles and derivatized with native histamine. The multivalent presentation of the immobilized ligands carried by the gold nanoparticles resulted in extremely low activation concentrations for histamine receptors on rat colonic epithelium. As a functional read-out system, chloride secretion resulting from stimulation of neuronal and epithelial histamine H1 and H2 receptors was measured in Ussing chamber experiments. These responses were strictly attributed to the histamine entities as histamine-free particles Au-MUDOLS or the monovalent ligand AcS-MUDA-HA proved to be ineffective. The vitality of the tissues used was not impaired by the nanoparticles.
Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: Linker effects on the relaxivity
Ferreira, Miguel F.,Gonalves, Janaina,Mousavi, Bibimaryam,Prata, Maria I. M.,Rodrigues, Srgio P. J.,Calle, Daniel,Lpez-Larrubia, Pilar,Cerdan, Sebastian,Rodrigues, Tiago B.,Ferreira, Paula M.,Helm, Lothar,Martins, Jos A.,Geraldes, Carlos F. G. C.
, p. 4016 - 4031 (2015/03/30)
The relaxivity displayed by Gd3+ chelates immobilized onto gold nanoparticles is the result of the complex interplay between the nanoparticle size, the water exchange rate and the chelate structure. In this work we study the effect of the length of ω-thioalkyl linkers, anchoring fast water exchanging Gd3+ chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd3+ chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(α-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM-1 s-1 (30 MHz, 25 °C), were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles was determined mainly by size. Small nanoparticles (HD = 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD = 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggest that functionalized gold nanoparticles hold great potential for further investigation as MRI contrast agents. This study contributes to a better understanding of the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd3+ complexes. It is a relevant contribution towards design rules for nanostructures functionalized with Gd3+ chelates as Contrast Agents for MRI and multimodal imaging. This journal is
A photolabile protection strategy for terminal alkynes
Gschneidtner, Tina A.,Moth-Poulsen, Kasper
supporting information, p. 5426 - 5429 (2013/09/23)
We present a strategy for photolabile protection of terminal alkynes. Several photo-caged alcohols were synthesized via mild copper(II)-catalyzed substitution between tertiary propargylic alcohols and 2-nitrobenzyl alcohol to build up robust, base stable o-nitrobenzyl (NB) photo-cleavable compounds. We compare the new photolabile protecting group with the commonly used alkyne protecting group, 2-methyl-3-butyn-2-ol and the results show that NB ethers are stable under the cleaving conditions for the cleavage of methylbutynol protected alkynes. Additionally, we present the synthesis of photo-cleavable NB derivatives containing thiol groups that can serve as agents for photoinduced surface functionalization reactions.
Visualization of latent fingermarks by nanotechnology: Reversed development on paper-a remedy to the variation in sweat composition
Jaber, Nimer,Lesniewski, Adam,Gabizon, Hadar,Shenawi, Sanaa,Mandler, Daniel,Almog, Joseph
supporting information, p. 12224 - 12227 (2013/02/23)
Don't sweat it: Negative fingermarks are developed on paper by the application of gold nanoparticles (gold circles) that are capped by a bifunctional ligand, and then silver precipitation. In this process, paper is the substrate and the fingermarks serve as a mask. This approach may contribute to the successful recovery of latent fingermarks by law enforcement agencies. Copyright
Preparation and antimicrobial behaviour of quaternary ammonium thiol derivatives able to be grafted on metal surfaces
Thebault, Pascal,Taffin de Givenchy, Elisabeth,Levy, Richard,Vandenberghe, Yves,Guittard, Frederic,Geribaldi, Serge
experimental part, p. 717 - 724 (2009/09/05)
New thiol derivatives containing a quaternary ammonium group bearing variable hydrocarbon chains via an amide connector or not between the sulphur and nitrogen atoms were synthesised with the future aim to be grafted on metal surfaces for obtaining contact-active auto-bactericidal surfaces. Their biostatic and bactericidal activities were evaluated against four microbial strains (Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus niger and Candida albicans). The presence of the thiol and amide functions in these surfactants was discussed in relation with the antimicrobial activity along with the influence of the length of alkyl chains in order to determine which molecular parameters are 'critical' for biological activity, and consequently what molecules must be chosen for grafting on metal surface.
Glyco-SAMs as glycocalyx mimetics: Synthesis of L-fucose- and D-mannose-terminated building blocks
Kleinert, Mike,Roeckendorf, Niels,Lindhorst, Thisbe K.
, p. 3931 - 3940 (2007/10/03)
In the course of a project on the supramolecular functions of the glycocalyx present on eukaryotic cell surfaces, it has been our goal to prepare spacer glycosides and cluster glycosides that are suitable for the formation of self-assembled monolayers (SAMs) on gold. We have selected amino-functionalized D-mannose and L-fucose derivatives for peptide coupling to thio-functionalised alkane and alkane-oligoethylene glycol spacers such as 12 and 15. Thus, a variety of thiospacered glycosides (16-19) and cluster glycosides (23, 24, 26, 28, and 29) were synthesized, which can be assembled on gold wafers to serve as glycocalyx mimetics. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Multiple Electron Tunneling Paths across Self-Assembled Monolayers of Alkanethiols with Attached Ruthenium(II/III) Redox Centers
Finklea, Harry O.,Liu, Luna,Ravenscroft Melissa S.,Punturi, Sesto
, p. 18852 - 18858 (2007/10/03)
Alkanethiol monolayers with pendant redox centers are deposited on gold electrodes by selfassembly.The monolayers are composed of both an electroactive thiol, HS(CH2)nC(O)NHCH2pyRu(NH3)5(2+/3+), with 10-15 methylene groups, and a diluent thiol, HS(CH2)mCOOH, also with 10-15 methylene groups.The monolayers are classified as "matched" (n = m), "exposed" ( n = 15, m = 10-14), and "buried" (n = 10, m = 11-15) according to the relative position of the redox center.Cyclic voltammograms in aqueous Na2SO4 indicate that the monolayers are close-packed with the redox centers residing in the aqueous phase in all but the most buried cases.Measurements of electron transfer kinetics by several methods (cyclic voltammetry, ac impedance spectroscopy, chronoamperometry) yield an internally consistent set of kinetic parameters, the standard rate constant ko, and the reorganization energy λ of the redox centers.The reorganization energies are in good agreement with the theoretically predicted value of 1.0 eV for the pyRu(NH3)5 redox centers.Plots of ln(ko) vs m are linear in all three cases.The slopes of the linear regression fit provide tunneling parameters (β, where ko ca. e-βm) of 0.97 +/- 0.03 (matched cases), 0,83 +/- 0.03 (exposed cases) and 0.16 +/- 0.02 (buried cases) per methylene.This pattern of β's is interpreted in terms of electronic coupling between the redox center and the electrode via both the redox thiol and the proximate diluent thiols, with the coupling via the diluent thiols dominating in the exposed cases.
A NEW LB FILM FORMING MOLECULE CONTAINING BOTH AN ELECTRO- AND PHOTOACTIVE PART
Burghard, M.,Schmelzer, M.,Roth, S.,Goepel, W.
, p. 39 - 48 (2007/10/02)
LB multilayers of the amphiphilic unsymmetrical disulphide S-(2-azobenzenethio)-11-mercapto-undecanoic acid (AMU) have been prepared and investigated by spectroscopic methods.A reversible photochromic switch can be observed upon film irradiation. - Keywords: photochromic, Langmuir-Blodgett film, ultrathin films, azobenzene, mercapto-alkanoic acids
Synthesis of Terminally Substituted 9-Alkylidene-10-methyl Acridans
Varveri, Fannie S.,Nikokavouras, John,Mantaka-Marketou, Anastasia E.,Micha-Screttas, Maria
, p. 967 - 972 (2007/10/02)
ω-Substituted undecanals 1 and 2 reacted with acridine derivatives 3 and 5 to give the terminally substituted 9-alkylidene-10-methylacridans 6.The compounds prepared were highly fluorescent and exhibited chemiluminescent activity. - Keywords: Acridans; Chemiluminescence.
