- Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins
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Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr4+, afforded better immobilization of the peptides and proteins and efficient capture of their targets.
- Forato, Florian,Liu, Hao,Benoit, Roland,Fayon, Franck,Charlier, Cathy,Fateh, Amina,Defontaine, Alain,Tellier, Charles,Talham, Daniel R.,Queffélec, Clémence,Bujoli, Bruno
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- Modular Assembly of Vibrationally and Electronically Coupled Rhenium Bipyridine Carbonyl Complexes on Silicon
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Hybrid inorganic/organic heterointerfaces are promising systems for next-generation photocatalytic, photovoltaic, and chemical-sensing applications. Their performance relies strongly on the development of robust and reliable surface passivation and functionalization protocols with (sub)molecular control. The structure, stability, and chemistry of the semiconductor surface determine the functionality of the hybrid assembly. Generally, these modification schemes have to be laboriously developed to satisfy the specific chemical demands of the semiconductor surface. The implementation of a chemically independent, yet highly selective, standardized surface functionalization scheme, compatible with nanoelectronic device fabrication, is of utmost technological relevance. Here, we introduce a modular surface assembly (MSA) approach that allows the covalent anchoring of molecular transition-metal complexes with sub-nanometer precision on any solid material by combining atomic layer deposition (ALD) and selectively self-assembled monolayers of phosphonic acids. ALD, as an essential tool in semiconductor device fabrication, is used to grow conformal aluminum oxide activation coatings, down to sub-nanometer thicknesses, on silicon surfaces to enable a selective step-by-step layer assembly of rhenium(I) bipyridine tricarbonyl molecular complexes. The modular surface assembly of molecular complexes generates precisely structured spatial ensembles with strong intermolecular vibrational and electronic coupling, as demonstrated by infrared spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy analysis. The structure of the MSA can be chosen to avoid electronic interactions with the semiconductor substrate to exclusively investigate the electronic interactions between the surface-immobilized molecular complexes.
- Allegretti, Francesco,Amati, Matteo,Barth, Johannes V.,Bartl, Johannes D.,Bondino, Federica,Cattani-Scholz, Anna,Deimel, Peter S.,Gregoratti, Luca,Henning, Alex,Magnano, Elena,Nickel, Bert,Ober, Martina F.,Ochsenfeld, Christian,Paulus, Claudia,Rieger, Bernhard,Savasci, G?kcen,Sharp, Ian D.,Stutzmann, Martin,Thomas, Christopher,Yazdanshenas, Bahar,Zeller, Patrick
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supporting information
p. 19505 - 19516
(2021/11/26)
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- SELECTIVE PLACEMENT OF CARBON NANOTUBES THROUGH FUNCTIONALIZATION
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The present invention provides a method for selectively placing carbon nanotubes on a substrate surface by using functionalized carbon nanotubes having an organic compound that is covalently bonded to such carbon nanotubes. The organic compound comprises at least two functional groups, the first of which is capable of forming covalent bonds with carbon nanotubes, and the second of which is capable of selectively bonding metal oxides. Such functionalized carbon nanotubes are contacted with a substrate surface that has at least one portion containing a metal oxide. The second functional group of the organic compound selectively bonds to the metal oxide, so as to selectively place the functionalized carbon nanotubes on the at least one portion of the substrate surface that comprises the metal oxide.
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Page/Page column 6
(2010/06/19)
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- Synthesis of methacrylate-functionalized phosphonates and phosphates with long alkyl-chain spacers and their self-aggregation in aqueous solutions
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Polymerizable amphiphilic organophosphorous compounds were synthesized and their self-aggregation behavior was investigated. The studied molecules contain a hydrophilic phosphorus end group, an alkyl chain spacer with a variable length from 3 to 11 CH2 groups and a polymerizable methacrylic group at the other chain end. Thus, the molecules represent a class of polymerizable surfactants. Two different reaction methods were used; either unsaturated alcohols or bromine-containing alcohols were applied as starting compounds for the preparation of the organophosphorous surfactants. The self-aggregation and micelle formation of the prepared compounds were investigated in aqueous solution by dynamic light scattering measurements. The critical micelle concentration of the P-containing amphiphiles was in all cases smaller than 0.040 mol/l and strongly dependent on the polarity of the phorphorous head group and the chain length of the spacer. Graphical abstract: [Figure not available: see fulltext.] The synthesis of organophosphorous amphiphiles as surface active monomers for the modification of metal oxide surfaces is presented. The spacer between the phosphorous head group and the methacrylate group was varied with regard to their length and composition. The self-aggregation behavior of these methacrylate-functionalized phosphates and phosphonates surfactants was investigated.
- Francova, Denisa,Kickelbick, Guido
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experimental part
p. 413 - 422
(2010/06/14)
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- Rapid in situ generation of two patterned chemoselective surface chemistries from a single hydroxy-terminated surface using controlled microfluidic oxidation
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In this work, we develop a new, rapid and inexpensive method to generatespatially controlled aldehyde and carboxylic acid surface groups by mic rofluidic oxidation of 11-hydroxyundecylphosphonic acid self-assembled monolayers (SAMs) on indium tin oxide (ITO) surfaces. SAMs are activated and patterned using a reversibly sealable, elastomeric polydimethylsiloxane cassette, fabricated with preformed micropatterns by soft lithography. By flowing the mild oxidant pyridinium chlorochromate through the microchannels, only selected areas of the SAM are chemically altered. This microfluidic oxidation strategy allows for ligand immobilization by two chemistries originating from a single SAM composition. ITO is robust, conductive, and transparent, making it an ideal platform for studying interfacial interactions. We display spatial control over the immobilizationof a variety of ligands on ITO and characterize the resulting oxime and amide linkages by electrochemistry, X-ray photoelectron spectroscopy, c ontact angle, fluorescence microscopy, and atomic force microscopy. Thisgeneral method may be used with many other materials to rapidly generat e patterned and tailored surfaces for studies ranging from molecular electronics to biospecific cell-based assays and biomolecular microarrays.
- Pulsipher, Abigail,Westcott, Nathan P.,Luo, Wei,Yousaf, Muhammad N.
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experimental part
p. 7626 - 7632
(2009/10/17)
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- Immobilization of chiral enzyme inhibitors on solid supports by amide-forming coupling and olefin metathesis
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The question whether phage display can be used as a selection method in the directed evolution of enantioselective enzymes has not been answered satisfactorily to date. In order to be able to test this in a specific case, namely in the hydrolytic kinetic
- Reetz, Manfred T,Rüggeberg, Carsten J,Dr?ge, Melloney J,Quax, Wim J
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p. 8465 - 8473
(2007/10/03)
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- Detection of discrete interactions upon rupture of au microcontacts to self-assembled monolayers terminated with -S(CO)CH3 or -SH
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Pulloff forces were measured under solvent for Au-coated atomic force microscopy (AFM) tips in contact with -S-acetate-, -O-acetate-, -SH-, or -OH-terminated self-assembled monolayers (SAMs). The SAMs were formed by adsorption of ω-functionalized undecylphosphonic acids on metal oxide substrates. In ethanol and hexadecane, the mean force required to rupture Au/S-acetate microcontacts was 7 times greater than the mean force required to break Au/O-acetate contacts, consistent with the known affinity of S-containing functional groups for Au. Further, rupture force histograms for Au/S-acetate microcontacts under ethanol or hexadecane showed 0.1 nN periodicity. Rupture forces for Au/-SH microcontacts were 4 times greater than for Au/-OH microcontacts under ethanol, and the rupture force histograms showed the same 0.1 nN periodicity. We have assigned this 0.1 nN force quantum to rupture of individual chemical bonds and have estimated the bond energy to be on the order of 10 kJ/mol. The specific interaction corresponding to this energy appears to be abstraction of Au atoms from the tip surface upon pulloff. Our ability to detect these discrete interactions was a function of the solvent in which the measurements were made. For example, in water there was no difference in the mean pulloff force for Au/S-acetate and Au/O-acetate contacts and the histograms did not exhibit periodicity. In general, mean rupture forces for tip-SAM microcontacts are strongly solvent-dependent. To observe single bond rupture forces directly, we argue that the tip-substrate interfacial energy must be negative and larger in absolute value than the substrate-solvent and tip-solvent interfacial energies [i.e., |γsubstrate-tip| > (γtip-solvent + γsubstrate-solvent)]. Otherwise, nonspecific solvent exclusion effects dominate the microcontact adhesion. These measurements show that, whereas rupture forces for tip-SAM microcontacts are solvent-dependent, these forces can be sensitive, under the right conditions, to fluctuations in the number of discrete chemical interactions.
- Skulason, Hjalti,Frisbie, C. Daniel
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p. 9750 - 9760
(2007/10/03)
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- A novel biotinylated suicide inhibitor for directed molecular evolution of lipolytic enzymes
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A bifunctional activity label (8)Scheme 1Reagents and conditions: (i) Me3SiCl, Et3N, CH2Cl2/ether; (ii) (EtO)3P/reflux; (iii) H2SO4/acetone; (iv) 1. COCl2, 2. N-hydrox
- Deussen,Danielsen,Breinholt,Borchert
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p. 507 - 513
(2007/10/03)
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