Micrometre and nanometre scale patterning of binary polymer brushes, supported lipid bilayers and proteins.

Binary polymer brush patterns were fabricated photodeprotection of an aminosilane with a photo-cleavable nitrophenyl protecting group. UV exposure of the silane film through a mask yields micrometre-scale amine-terminated regions that can be derivatised to incorporate a bromine initiator to facilitate polymer brush growth atom transfer radical polymerisation (ATRP). Atomic force microscopy (AFM) and imaging secondary ion mass spectrometry (SIMS) confirm that relatively thick brushes can be grown with high spatial confinement.

Simple, Direct Routes to Polymer Brush Traps and Nanostructures for Studies of Diffusional Transport in Supported Lipid Bilayers.

Patterned poly(oligo ethylene glycol) methyl ether methacrylate (POEGMEMA) brush structures may be formed by using a combination of atom-transfer radical polymerization (ATRP) and UV photopatterning. UV photolysis is used to selectively dechlorinate films of 4-(chloromethyl)phenyltrichlorosilane (CMPTS) adsorbed on silica surfaces, by exposure either through a mask or using a two-beam interferometer. Exposure through a mask yields patterns of carboxylic acid-terminated adsorbates.

Fabrication of Two-Component, Brush-on-Brush Topographical Microstructures by Combination of Atom-Transfer Radical Polymerization with Polymer End-Functionalization and Photopatterning.

Poly(oligoethylene glycol methyl ether methacrylate) (POEGMEMA) brushes, grown from silicon oxide surfaces by surface-initiated atom transfer radical polymerization (SI-ATRP), were end-capped by reaction with sodium azide leading to effective termination of polymerization. Reduction of the terminal azide to an amine, followed by derivatization with the reagent of choice, enabled end-functionalization of the polymers. Reaction with bromoisobutryl bromide yielded a terminal bromine atom that could be used as an initiator for ATRP with a second, contrasting monomer (methacrylic acid).

Influence of fermentation conditions on the surface properties and adhesion of Lactobacillus rhamnosus GG.

Background: The surface properties of probiotic bacteria influence to a large extent their interactions within the gut ecosystem. There is limited amount of information on the effect of the production process on the surface properties of probiotic lactobacilli in relation to the mechanisms of their adhesion to the gastrointestinal mucosa. The aim of this work was to investigate the effect of the fermentation pH and temperature on the surface properties and adhesion ability to Caco-2 cells of the probiotic strain Lactobacillus rhamnosus GG.

Quantitative investigation of the photodegradation of polyethylene terephthalate film by friction force microscopy, contact-angle goniometry, and X-ray photoelectron spectroscopy.

Studies of the UV-induced photodegradation of poly(ethylene terephthalate) (PET) have been carried out using contact-angle goniometry, X-ray photoelectron spectroscopy (XPS), and friction force microscopy (FFM). The advancing contact angle of water, theta, decreased following exposure of free-standing PET films to UV light. Measurements of surface friction by FFM showed that the coefficient of friction mu increased as the degradation proceeded, reaching a limiting value after ca 200 min, in agreement with the contact angle data.

Fabrication of submicrometer biomolecular patterns by near-field exposure of plasma-polymerized tetraglyme films.

Plasma-polymerized tetraglyme films (PP4G) have been modified by exposure to ultraviolet (UV) light from a frequency-doubled argon ion laser (244 nm) and characterized using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). XPS data indicated that the ether component of the C 1s spectrum declined after UV exposure, while components due to carbonyl and carboxylate groups increased. The film was physically eroded by UV exposure: after 100 s the rate of erosion reached a steady state of 0.

Influence of the solvent environment on the contact mechanics of tip-sample interactions in friction force microscopy of poly(ethylene terephthalate) films.

Friction force microscopy measurements have been carried out on free-standing films of poly(ethylene terephthalate) in a variety of different media. In ethanol, the adhesion force was small, and the friction-load relationship was linear. In perfluorodecalin, nonlinearity was observed in the friction-load relationship, and the data have been found to fit the Johnson-Kendall-Roberts model of contact mechanics.