Relationship between adsorbed fibronectin and cell adhesion on a honeycomb-patterned film

Substratum surface morphology plays a vital roles in cellular behavior. Here, we characterized adsorption of fibronectin (Fn) as a typical cell adhesion protein onto honeycomb-patterned films made of poly(ε-caprolactone) (PCL) by using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). In order to determine how cells adhere to a honeycomb-patterned film, focal adhesion of cardiac myocytes (CMYs) and endothelial cells (ECs) on the films were studied by using fluorescence labeling of vinculin. Fn adsorbs around the pore edges to form ring-shaped structures. CMYs and ECs adhere onto the honeycomb-patterned films at focal contact points localized around pore edges distributed over the entire cellular surface. The focal contact points on the honeycomb-patterned films correspond well with the adsorption sites of Fn. We suggest that the cell response to honeycomb-patterned films is associated with the adsorption pattern of Fn on the film.     

The Association of Tetraalkylammonium Ions with Poly(vinyl methyl ether) in Water and its Effect on Phase‐Separation Behavior as Studied by Micro‐Raman Spectroscopy

Summary: The thermosensitive phase‐separation of poly(vinyl methyl ether) in water has been investigated by micro‐Raman spectroscopy in the presence of tetraalkylammonium bromides. The equilibrium distribution of both polymer and salts to the polymer‐rich and solvent‐rich phases was determined as a function of temperature. Tetraalkylammonium ions with longer alkyl chains associate more strongly with PVME and raise the phase‐transition temperature due to an increase in hydrophilicity.

     

Clarification on the Reactivity of Diaryl Diselenides toward Hexacyclohexyldilead under Light

In this study, the reactivity of organochalcogen compounds toward a representative alkyl-lead bond compound under light was investigated in detail. Under light irradiation, the Cy-Pb bond of Cy₆Pb₂ (Cy = cyclohexyl) undergoes homolytic cleavage to generate a cyclohexyl radical (Cy•). This radical can be successfully captured by diphenyl diselenide, which exhibits excellent carbon-radical-capturing ability. In the case of (PhS)₂ and (PhTe)₂, the yields of the corresponding cyclohexyl sulfides and tellurides were lower than that of (PhSe)₂. This probably occurred due to the low carbon-radical-capturing ability of (PhS)₂ and the high photosensitivity of the cyclohexyl-tellurium bond.     

Synthesis of a New Thiophene/Quinoxaline CT‐Type Copolymer with High Solubility and Its Basic Optical Properties

A new π‐conjugated charge‐transfer‐type copolymer of electron‐donating thiophene and electron‐accepting quinoxaline was prepared by organometallic polycondensation. The polymer was soluble in organic solvents such as tetrahydrofuran, and showed a UV‐vis peak at long wavelengths of 598 nm in chloroform and 629 nm in the film. Its film exhibited a χ⁽³⁾ peak in the resonance region with a χ⁽³⁾ value comparable to that of regioregular head‐to‐tail poly(3‐hexylthiophene‐2,5‐diyl).

     

Fluorescence Studies of Pyrene‐Labeled Cholesterol‐Bearing Polymer Films

Copolymers of cholesteryl 6‐methacryloyloxy hexanoate and (1‐pyrenemethyl) 6‐methacryloyloxy hexanoate were prepared by free radical polymerization, with the amount of (1‐pyrenemethyl) 6‐methacryloyloxy hexanoate units (f_Py) in the polymers ranging from 0–100 mol‐%. The copolymers with f_Py ≤ 20.0 mol‐% show distinct liquid‐crystalline (LC) phase behavior. According to the fluorescence of pyrene in these copolymer LC films, each pyrene moiety is individually incorporated into the LC domain, and the interaction between the pyrene moieties is restricted.