A wet photolithographic route for micropatterning fluid phospholipid bilayers is demonstrated in which spatially directed illumination by short-wavelength ultraviolet radiation results in highly localized photochemical degradation of the exposed lipids. Using this method, we can directly engineer patterns of hydrophilic voids within a fluid membrane as well as isolated membrane corrals over large substrate areas. We show that the lipid-free regions can be refilled by the same or other lipids and lipid mixtures which establish contiguity with the existing membrane, thereby providing a synthetic means for manipulating membrane compositions, engineering metastable membrane microdomains, probing 2D lipid-lipid mixing, and designing membrane-embedded arrays of soluble proteins. Following this route, new constructs can be envisaged for high-throughput membrane proteomic, biosensor array, and spatially directed, aqueous-phase material synthesis.

Al molar ratio of 2:1 was titrated with 0.1 M NaOH solution to approximately pH 9.5 under an N 2 atmosphere and aged for 24 h with vigorous stirring. The resulting white precipitate was collected by centrifugation and washed thoroughly with decarbonated water. The DNA±LDH hybrid was then prepared by intercalating doublestranded DNA into the interlayer space of the pristine LDH by an anion-exchange route. The DNA solution (2.6 mg mL ±1 ) was added to the LDH suspension (1 mg mL ±1 ) and mixed together in a shaking incubator for 7 days at 65 C. The resulting DNA±LDH hybrid was collected by centrifugation and washed with decarbonated water. For the preparation of PEO-coated DNA±LDH hybrid, 0.05 g of the DNA±LDH hybrid was dispersed in 50 mL of EtOH, and 50 mL of 0.5 % PEO±EtOH solution was added. After 30 min the PEO-coated DNA±LDH hybrid was washed with EtOH and then dried.Preparation of PPY-MAG Hybrid: The MAG (maghemite) nanoparticles were prepared by the method of Massart et al. [15,16] 3+ ratio of 0.5 were dissolved in deionized water, and heated to 50 C. Then, 150 mL of 8.6 M NH 4 OH solution was quickly added to the solution with vigorous mechanical stirring. The precipitated magnetite (Fe 3 O 4 ) was washed with deionized water and acetone, and magnetically decanted to remove the chloride ions and other non-magnetic impurities. The obtained magnetite was easily oxidized to maghemite as follows [13,17]. The magnetite (18 g) was treated with 2 M nitric acid solution for 15 min and 300 mL of aqueous 0.33 M iron(III) nitrate solution was then added. The resulting mixture was then boiled for another 15 min. The resulting maghemite particles were washed and dried in vacuo for subsequent polypyrrole coating. 1.7 g of maghemite was dispersed in liquid pyrrole for 30 min, and excess pyrrole was removed by magnetic decantation. This maghemite/pyrrole mixture was added to 200 mL of 0.15 M FeCl 3 /EtOH solution with stirring for 30 min to polymerize the surface pyrrole. Finally, the PPY/cFe 2 O 3 nanohybrids were washed with ethanol, separated by magnetic decantation, and dried in vacuo.DNA Stability Test under Enzyme Conditions: 96 units of DNase I (purchased from Sigma) was added to the DNA±LDH hybrid (15 lg) mixed with Ca 2+ /Mg 2+ ions and incubated at 37 C. After 2 h, the activation of DNase I was stopped by heating to 75 C for 30 min. The hybrid was then washed with decarbonated water. For the recovery of DNA from the hybrid, both the as-prepared DNA±LDH hybrid and the DNase I treated sample were acidified to a pH of about 2 with 0.01 M HCl solution for 30 min. The extracted DNA strands were amplified by PCR. Typical PCR was performed in 25 lL PCR buffer containing 200 lM of dNTPs (deoxynucleoside triphosphates), 0.2 lM of forward primer (AGGGT CGAAG TACGG AATAC), 0.2 lM of reverse primer (GTCCG GAGCA CTCCG CTCCG) and 1 U of Taq polymerase (Nova-taq, Genenmed). Thermocycling was at 95 C for 10 min followed by 35 cycles of 95 C for 30 s, 60 C for 30 s, 72 C for 30 s, and then 72 C for 10 min.

Here we present a spatially directed calcination approach based on masked UV exposure to pattern mesoporous regions within a mesostructured matrix in a rapid, single-step, and inexpensive manner. Subsequent chemical treatment of the film can selectively remove the mesostructured regions, leading to patterned mesoporous structures. Such tunability in the processing under near room-temperature conditions allows for spatial control and patterning of function related to optical properties, topology, porosity, hydrophobicity, and structural morphology of the mesoscopic thin film material on a wide range of substrates.

The evolution of photochemical surfactant removal and silica condensation from organically templated thin film silica nanocomposites with mesoscopic ordering has been probed using a combined application of Fourier transform infrared (FT-IR) spectroscopy and single wavelength ellipsometry. Thin films of silica nanocomposites were prepared by a previously reported evaporation-induced self-assembly process. Specifically, oxidized silicon and gold substrates were withdrawn at 25 mm/min from a subcritical micelle concentration solution containing an ethylene oxide surfactant as a structure-directing agent and tetraethyl orthosilicate as a silica precursor. Real-time grazing incidence difference FT-IR spectra of the nanocomposite films on gold taken during exposure to short-wavelength ultraviolet light (184-257 nm) show that surfactant removal and silica condensation occur gradually and concomitantly. Surfactant removal and silica reconstructions were found to be nearly complete after 90 min of exposure. Further, a transient feature was observed in the FT-IR spectra around 1713 cm(-1) during the UV exposure process and was assigned to a carbonyl (C=O) stretching mode absorption, reflecting the transient formation of a partially oxidized surfactant intermediate. From these data we propose a stepwise model for surfactant removal from the nanocomposite films. Ellipsometrically determined index of refraction values collected as a function of UV exposure are also shown to support such a stepwise mechanism of surfactant removal from the ordered nanocomposite silica thin film mesophases studied here.

The integration of ion-channel transport functions with responses derived from nanostructured and nanoporous silica mesophase materials is demonstrated. Patterned thin-film mesophases consisting of alternating hydrophilic nanoporous regions and hydrophobic nanostructured regions allow for spatially localized proton transport via selective dimerization of gramicidin in lipid bilayers formed on the hydrophilic regions. The adjoining hydrophobic mesostructure doped with a pH sensitive dye reports the transport. The ease of integrating functional membranes and reporters through the use of patterned mesophases should enable high throughput studies of membrane transport.

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In recent years, methods have been developed for the generation of complex ordered nanocomposite materials through organic templating of inorganic structures. One approach involves preparation of composite materials by an evaporation induced self-assembly process involving organization of organic surfactants and formation of inorganic silica from soluble precursors. Recently, we have shown that deep-UV light (185–254nm) is efficient at removing the surfactant microphase for a routine production of well-ordered mesoporous silica thin films. Here we probe the evolution of surfactant removal from nanocomposite thin film silica mesophases as a function of deep-UV exposure using a combined application of FTIR and single wavelength ellipsometry. Taken together, these data indicate that surfactant removal occurs in a step-wise fashion with the formation of oxidized intermediates prior to complete removal of the surfactant from the thin film.