We consider a polymer brush grafted to a surface (acting as an electrode) and bearing a charged group at its free end. Using a second distant electrode, the brush is subject to a constant electric field. Based on a coarse-grained continuum model, we calculate the average brush height and find that the brush can stretch or compress depending on the applied field and charge end-group. We further ...

The presence of polymer chains grafted or adsorbed onto a surface can dramatically alter the forces that affect interactions between surfaces. The equilibrium properties of such polymer brush systems have been studied for the past two decades, yielding general agreement between theory and experiment. Conversely, the nonequilibrium properties of polymer brushes are still under intense theoretica...

BACKGROUND High-risk human papillomavirus (HR-HPV) infection is associated with improved prognosis and a better response to treatment in patients with oropharyngeal squamous cell carcinoma (OPSCC). Brush cytology is a noninvasive method with which to collect cells from the surface of mucosal lesions. The objective of the current study was to assess the performance of OPSCC brush cytology for th...

We reported previously that the absorption of cholesterol and long-chain cholesteryl esters by rabbit small-intestinal brush border membranes (BBMV) is protein-mediated (Thurnhofer, H., and H. Hauser. 1990. Biochemistry. 29:2142-2148; Compassi, S., M. Werder, D. Boffelli, F. E. Weber, H. Hauser, and G. Schulthess. 1995. Biochemistry. 34: 16473-16482). Evidence is presented for similar cholester...

PURPOSE To compare the efficacy of an oscillating-rotating power toothbrush with a novel brush head incorporating angled CrissCross bristles (Oral-B Pro 7000 SmartSeries and Oral-B CrossAction brush head) versus a marketed sonic toothbrush (Colgate ProClinical A1500 with the Triple Clean brush head) in the reduction of gingivitis and plaque over a 6-week period. METHODS This was a single cent...

The brush border of intestinal epithelial cells consists of an array of tightly packed microvilli. Within each microvillus is a bundle of 20-30 actin filaments. The basal ends of the filament bundles are embedded in and interconected by a filamentous meshwork, the terminal web, which lies directly beneath the microvilli. When calcium and ATP are added to isolated brush borders that have been tr...

Using molecular dynamics simulations, we study the lubricating properties of neutral and charged bottle-brush coatings as a function of the compression and shear stresses and brush grafting density. Our simulations have shown that in charged bottle-brush systems under shear there is a layer with excess counterions located in the middle between brush-bearing surfaces. The main deformation mode o...

Designable media can control properties of nanocomposite materials by spatially organizing nanoparticles. Here we theoretically study particle organization by ultrathin polymer films of grafted chains ("brushes"). Polymer-soluble nanoparticles smaller than a brush-determined threshold disperse in the film to a depth scaling inversely with particle volume. In the polymer-insoluble case, aggregat...

We investigate the mechanical properties of ultra-thin layers of polystyrene/poly (2-vinylpyridine) (PS/P2VP) block copolymers by means of a Surface Forces Apparatus adapted to operate as a rheometer at the molecular level. Two systems are studied: "brush/wall" and "brush/brush". A comparison of the normal force curves shows that when brushes are compressed against each other, they contract rat...