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Alignment of liquid crystal/carbon nanotube dispersions for application in unconventional computing

We demonstrate the manipulation of single-walled carbon nanotube/liquid crystal composites using in-plane electric fields. The conductivity of the materials is shown to be dependant on the application of a DC bias across the electrodes. When the materials are subjected to this in-plane field, it is suggested that the liquid crystals orientate, thereby forcing the SWCNTs to follow in alignment. Thi

Exploring the alignment of carbon nanotubes dispersed in a liquid crystal matrix using coplanar electrodes

We report on the use of a liquid crystalline host medium to align single-walled carbon nanotubes in an electric field using an in-plane electrode configuration. Electron microscopy reveals that the nanotubes orient in the field with a resulting increase in the DC conductivity in the field direction. Current versus voltage measurements on the composite show a nonlinear behavior, which was modelled

Microfluidic electronic tongue

Fast, simple inspection of liquids such as coffee, wine and body fluids is highly desirable for food, beverage and clinical analysis. Electronic tongues are sensors capable of performing quantitative and qualitative measurements in liquid substances using multivariate analysis tools. Earlier attempts to fulfil this task using only a few drops (microliters) of sample did not yield rational results

Exploring copper nanostructures as highly uniform and reproducible substrates for plasmon-enhanced fluorescence

The unique properties of metallic nanostructures of coinage metals that can sustain localized surface plasmon resonances (LSPR) put them at the centre of plasmon-enhanced phenomena. The theory of plasmonic phenomena based on LSPR is well-established. However, the fabrication of plasmonic substrates, reproducibly, is still challenging for applications in surface-enhanced Raman scattering (SERS) and

Plasmon-Enhanced Scattering and Fluorescence Used for Ultrasensitive Detection in Langmuir-Blodgett Monolayers

The artificial bilayer structures of lipids and phospholipids can be fabricated using the Langmuir-Blodgett (LB) technique. High sensitivity and ultrasensitive detection can only be achieved using plasmon-enhanced spectroscopy, such as surface-enhanced Raman scattering (SERS). This chapter describes the single molecule detection of tagged-phospholipids using the LB technique and plasmon-enhanced s

Chitosan does not inhibit enzymatic action of human pancreatic lipase in Langmuir monolayers of 1,2-didecanoyl-glycerol (DDG)

In this study, we tested the hypothesis according to which chitosan reduces lipid digestion by blocking the access of lipases to ingested fat. Because lipase action takes place mostly at interfaces, we produced Langmuir films of 1,2-didecanoyl-glycerol (DDG), which is the substrate for human pancreatic lipase (HPL). The experimental assays were carried out in acidic medium, at pH 3.0, to ensure th

Amperometric detection of lactose using -galactosidase immobilized in layer-by-layer films

A direct, low-cost method to determine the concentration of lactose is an important goal with possible impact in various types of industry. In this study, a biosensor is reported that exploits the specific interaction between lactose and the enzyme β-galactosidase (β-Gal) normally employed to process lactose into glucose and galactose for lactose-intolerant people. The biosensor was made with β-Ga

On the distinct molecular architectures of dipping- and spray-LbL films containing lipid vesicles

The introduction of spraying procedures to fabricate layer-by-layer (LbL) films has brought new possibilities for the control of molecular architectures and for making the LbL technique compliant with industrial processes. In this study we show that significantly distinct architectures are produced for dipping and spray-LbL films of the same components, which included DODAB/DPPG vesicles. The film

Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces

Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir-Blodgett (LB) and layer-by-layer (LbL) films used to simulate bi

Toward the optimization of an e-tongue system using information visualization : A case study with perylene tetracarboxylic derivative films in the sensing units

The wide variety of molecular architectures used in sensors and biosensors and the large amount of data generated with some principles of detection have motivated the use of computational methods, such as information visualization techniques, not only to handle the data but also to optimize sensing performance. In this study, we combine projection techniques with micro-Raman scattering and atomic

Large-area plasmonic substrate of silver-coated iron oxide nanorod arrays for plasmon-enhanced spectroscopy

One-dimensional iron oxide materials fabricated on conducting glass substrates and their unique properties make these nanostructures promising candidates for a wide range of applications. Herein, vertically oriented α-Fe2O3 nanorod arrays synthesized under hydrothermal conditions over a large area are described, as an active platform for surface-enhanced resonance Raman scattering (SERRS) and surf

Physical vapor deposited thin films of lignins extracted from sugar cane bagasse : Morphology, electrical properties, and sensing applications

The concern related to the environmental degradation and to the exhaustion of natural resources has induced the research on biodegradable materials obtained from renewable sources, which involves fundamental properties and general application. In this context, we have fabricated thin films of lignins, which were extracted from sugar cane bagasse via modified organosolv process using ethanol as org

Study of the interaction between cardiolipin bilayers and methylene blue in polymer-based Layer-by-Layer and Langmuir films applied as membrane mimetic systems

An increase of the reports involving mimetic systems has been observed. Briefly, these systems use biological phospholipids to exploit specific interactions between membrane-models and drugs. Here, the Layer-by-Layer (LbL) and Langmuir techniques were used to investigate the interaction between cardiolipin (CLP - negative phospholipid) and a cationic-like drug methylene blue (MB). Supported by a c

Isolation and characterization of a resident tolerant Saccharomyces cerevisiae strain from a spent sulfite liquor fermentation plant

Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production. However, depending on the pulping process conditions, the release of monosaccharides also generates a range of compounds that negatively affect microbial fermentation. In the present study, we investigated whether endogenous yeasts in SSL-based ethanol plant could