A Nanoscale Adhesion Layer to Promote Cell Attachment on PEEK

A Nanoscale Adhesion Layer to Promote Cell Attachment on PEE

Titanium(III)-Promoted Stereoselective Synthesis of Simple <i>C</i>-Glycosides

Titanium(III)-Promoted Stereoselective Synthesis of Simple C-Glycoside

Surface Modification of Y₂O₃ Nanoparticles

Rare earth ion-doped yttrium oxide (Y2O3) nanocrystals are nontoxic and can be prepared as upconversion materials for cellular imaging, but they do not suspend well in water. In contrast to their tendency to dissolve in acidic media, yttria (Y2O3) nanoparticles readily react with phosphonic acids to give phosphonate-bonded yttria particles. Through the choice of phosphonic acid, the hydrophilicity of the nanoparticles can be controlled. The synthesis of a novel tetraethylene glycol-derived phosphonic acid is described; yttria treated with the corresponding phosphonate is easily dispersed in aqueous media. The preparation of yttria bonded to a phosphonate that may be used for cross coupling with biomolecules is also described

Highly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy

A highly sensitive technique is reported to detect NO using X-ray photoelectron spectroscopy (XPS) of a silicon-bound iron hemelike complex. A self-assembled monolayer of an hydroxyalkylphosphonic acid was grown on the native oxide surface of silicon and was used for covalent attachment of hematin. XPS analysis for the hematin nitrogens gives a single peak in the N(1s) region. After reaction with NO, a new, distinct peak is observed in the N1s spectrum, at approximately 5.5 eV higher binding energy, which is attributed to the heme-bound NO. On the basis of measurements of surface loading of hematin species using quartz crystal microgravimmetry and XPS, detection of ≤50 picomoles of NO in the sampled region can be accomplished

Rapid Preparation of Variously Protected Glycals Using Titanium(III)

Glycosyl chlorides and bromides can be rapidly converted to glycals in high yield by reaction with (Cp2Ti[III]Cl)2. This reagent tolerates a wide range of common carbohydrate protecting groups, including silyl ethers, acetals, and esters; the methodology provides a general route for the preparation of glycals substituted with both acid- and base-labile functionality. A reaction mechanism is proposed that is based on heteroatom abstraction to give an intermediate glycosyl radical. This radical reacts with a second equivalent of Ti(III) to yield a glycosyltitanium(IV) species. β-Heteroatom elimination from the glycosyltitanium(IV) complex gives the glycal

A Modular Monolayer Coating Enables Cell Targeting by Luminescent Yttria Nanoparticles

Luminescent Eu3+-doped Y2O3 nanoparticles are functionalized for cell targeting using a modular, multisegmented approach based on a phosphonate monolayer platform. The first segment provides hydrolytic stability for the particle−organic interface; the second enables aqueous suspendability; the third is used to bond cell attachment molecules. In vitro imaging experiments showed enhanced cell attachment of activated nanoparticles conjugated with cell attachment peptides compared to control nanoparticles. Peptide-derivatized nanoparticles are not displaced from the cells by their soluble peptide analogue, which suggests strong, polyvalent cell−particle interactions

A Nanoscale Interface Improves Attachment of Cast Polymers to Glass

A novel interface was prepared on glass slides that stabilizes several cast polymers against delamination under conditions necessary for the study of cell surface interactions. This interface was synthesized by deposition of zirconium tetra(tert-butoxide) from the vapor phase onto the glass followed by mild thermolysis, which gives a surface-bound zirconium oxide coating. This oxide coating improved attachment of polymer coatings cast from formic acid or methylene chloride. Nylon, polyurethane, and polyhydroxybutyrate/polyhydroxyvalerate coatings were stable against delamination from the oxide-coated glass following sonication in ethanol for more than 30 min or immersion in water at pH 8 for at least 48 h

Organometallic Chemistry at the Magnesium− Tris(8-hydroxyquinolino)aluminum Interface

Organometallic Chemistry at the Magnesium− Tris(8-hydroxyquinolino)aluminum Interfac

Reaction of Tetra(<i>tert</i>-Butoxy)Tin or -Zirconium with Hydroxylated Titanium in Ultrahigh Vacuum: Contrasting Reactivity with Hydroxylated Aluminum Substrate

Reaction of Tetra(tert-Butoxy)Tin or -Zirconium with Hydroxylated Titanium in Ultrahigh Vacuum:  Contrasting Reactivity with Hydroxylated Aluminum Substrat

Characterization of Self-Assembled Organic Films Using Differential Charging in X-ray Photoelectron Spectroscopy

Differential charging is often regarded as a problem in X-ray photoelectron spectroscopic studies, especially for insulating or partially conducting samples. Application of a positive bias can reduce the effect of differential charging by attracting stray electrons from the system, thereby compensating for the electron loss. On the other hand, differential charging effect can be enhanced by the application of a negative bias to the sample during spectrum acquisition. The successful use of the differential charging technique to distinguish between multi- and monolayer organophosphonate films on oxide-covered silicon has been reported. A detailed description of this technique is now presented which shows how differential charging can be used as an important tool for the characterization of self-assembled films deposited on various surfaces. The dependence of this technique on the conductivity of the substrate has been investigated by studying the spectral behavior of the deposited films of phosphonic acid on conducting, semiconducting, and insulating samples (stainless steel, silicon, and glass). Application of either positive or negative dc electrical bias affects the carbon core-level (C1s) line shape and intensity, which is dependent on the atom's physical location above the surface