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

Abstract

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. POEGMEMA may be grown from intact Cl initiators that were masked during exposure. Corrals, traps, and other structures formed in this way enable the patterning of proteins, vesicles, and, following vesicle rupture, supported lipid bilayers (SLBs). Bilayers adsorbed on the carboxylic acid-terminated surfaces formed by C–Cl bond photolysis in CMPTS exhibit high mobility. SLBs do not form on POEGMEMA. Using traps consisting of carboxylic acid-functionalized regions enclosed by POEGMEMA structures, electrophoresis may be observed in lipid bilayers containing a small amount of a fluorescent dye. Segregation of dye at one end of the traps was measured by fluorescence microscopy. The increase in the fluorescence intensity was found to be proportional to the trap length, while the time taken to reach the maximum value was inversely proportional to the trap length, indicating uniform, rapid diffusion in all of the traps. Nanostructured materials were formed using interferometric lithography. Channels were defined by exposure of CMPTS films to maxima in the interferogram, and POEGMEMA walls were formed by ATRP. As for the micrometer-scale patterns, bilayers did not form on the POEGMEMA structures, and high lipid mobilities were measured in the polymer-free regions of the channels.

Fabrication of microstructured binary polymer brush “corrals” with integral pH sensing for studies of proton transport in model membrane systems

“…In both cases residual lipid vesicles with a diameter of several microns can be observed. However, the difference in contrast between the brush walls and brush wells is significantly larger in the presence of pR than in its absence, when the low-level of background emission from the labelled lipids (present at ∼1% the concentration of NBC in the lipid-resistant POEGMA brushes, 36 , 68 present as a diagnostic device to confirm membrane formation) 71 appears to be more significant.…”

Photosynthetic Model Membranes of Natural Plant Thylakoid Embedded in a Patterned Polymeric Lipid Bilayer

“…The sensor crystals were cleaned in 0.1 M SDS solution (immersed for 30 min at 30 °C), rinsed with deionized water, and dried under a nitrogen stream. For the measurements, the sensor crystal was oscillated at its resonance frequency of 5 MHz and at three harmonics (25,35,and 45 MHz), and the shifts of frequency (Δf) and dissipation (ΔD) were monitored. The interval for data acquisition was 0.2 s. The mounted QCM sensor crystal was first equilibrated with a degassed buffer solution at 21.8 °C.…”

“…have been reconstituted in a substrate-supported model membrane to study their lateral organization, − clustering, , membrane stacking, − and potential as nanomaterials . Supported membrane systems are amenable to highly sensitive interfacial analyses (including AFM), and they can be generated in a designed pattern, − which greatly enhances their utility in analyzing the photosynthetic reactions. However, the studies using supported membranes thus far had only two choices, i.e.…”

Tools for Low-Dimensional Chemistry

“…Figure 7 shows a schematic diagram for the procedure used. 43 A film of CMPTS on a glass surface is exposed to UV light through a mask, leading to dehalogenation in exposed regions. In the masked areas, the chloromethyl groups remain intact, and poly(oligothylene glycol methacrylate) (POEGMA) brushes can be grown.…”

“…Figure shows a schematic diagram for the procedure used . A film of CMPTS on a glass surface is exposed to UV light through a mask, leading to dehalogenation in exposed regions.…”