Chloride ion-selective dye liquid nanoemulsion: improved sensor performance due to intermolecular interactions between dye and ionophore.

Ionophore-based dye liquid nanoemulsion sensors exhibiting rapid response, high selectivity, and high sensitivity to chloride were developed. Since nanoemulsions contain extremely high concentrations of dyes and have large surface areas, rapid and highly sensitive measurements were possible. H-NMR measurements revealed intermolecular interactions between the dye and the ionophore, which contributed to the suppression of the background signal.

Enzyme-responsive fluorescent nanoemulsion based on lipophilic dye liquid.

An enzyme-responsive fluorescent nanoemulsion (NE) based on lipophilic dye liquid (LDL) was developed for alkaline phosphatase (ALP). The response mechanism of the NE involved enzymatic reactions and simultaneous extraction of anions. The LDL-based NE exhibited 3.

Lipophilic Fluorescent Dye Liquids: Förster Resonance Energy Transfer-Based Fluorescence Amplification for Ion Selective Optical Sensors Based on a Solvent Polymeric Membrane.

Optical sensors based on solvent polymeric membranes have the potential to measure analytes present in an aqueous solution through the development of a tailored method for a specific target. However, limits in the concentrations of the component dyes have prevented improvements in sensitivity. We propose a Förster resonance energy transfer (FRET)-based fluorescence amplification system for ion-selective optical sensors using a highly fluorescent liquid material composed of a lipophilic phosphonium cation and a pyrene modifying sulfonate anion ([P][HP-SO]), as both the plasticizer and donor, in addition to a combination of the lipophilic phosphonium cation and the fluorescein dodecyl ester anion ([P][12-FL]) as the fluorescent sensing dye acceptor.

Highly sensitive optical ion sensor with ionic liquid-based colorimetric membrane/photonic crystal hybrid structure.

An ionic liquid-based thin (~ 1 µm) colorimetric membrane (CM) is a key nano-tool for optical ion sensing, and a two-dimensional photonic crystal slab (PCS) is an important nano-platform for ultimate light control. For highly sensitive optical ion sensing, this report proposes a hybrid of these two optical nano-elements, namely, a CM/PCS hybrid. This structure was successfully fabricated by a simple and rapid process using nanoimprinting and spin-coating, which enabled control of the CM thickness.

A lipophilic ionic liquid-based dye for anion optodes: importance of dye lipophilicity and application to heparin measurement.

Herein, a fully lipophilic ionic liquid (IL) comprising a lipophilic fluorescein anion and a trihexyltetradecylphosphonium cation was synthesized and used as the plasticizer for a plasticized poly(vinyl chloride) (PVC) membrane optode. Systematic investigation of the alkyl chain length of the fluorescein anion proved the significance of lipophilicity for obtaining the reversible absorbance measurements. A PVC membrane fabricated with the synthesized lipophilic IL was observed to comprise an unusually high dye concentration (915 mmol kg) and exhibited good sensitivity as well as response time in its sensor performance.

Enzyme-responsive Fluorescent Ionic Liquid.

Herein, we describe the development of a novel material, "enzyme-responsive fluorescent ionic liquid", which enabled a highly sensitive detection of alkaline phosphatase (ALP). We prepared a plasticized poly(vinyl chloride) (PVC) membrane using this new material as a plasticizer and quantified ALP in aqueous solutions. Preliminary results suggested that the PVC membrane responded to ALP at an interface between the membrane and the sample solution with anion extraction to maintain electroneutrality in the membrane phase.

An ionic liquid composed of purely functional sensing molecules: a colorimetrically calcium responsive ionic liquid.

A highly lipophilic ionic liquid (IL) consisting of stoichiometrically equal amounts of two purely functional chemical sensing molecules, an anionic calcium ionophore and a cationic dye, was synthesized for the first time, and used as a component for a poly(vinyl chloride)-based or neat liquid membrane optical sensor. This is the first report of an IL consisting of purely functional chemical sensing molecules, which is completely different from the previously reported ionic liquids typically consisting of imidazolium or other lipophilic cations. Since the present IL contained an extremely high concentration of dyes, the IL-based sensor showed dramatically enhanced sensitivity (13 times higher compared to that of a conventional sensor), and fully reversible and selective response to Ca2+.

Regioselective Immobilization of a PVC Membrane Composed of an Ionic Liquid-based Dye on Convex-shaped PDMS Surface for Multiplexed Microanalytical Devices.

A novel method for the intact immobilization of a very-thin and soft PVC membrane on a convex-shaped poly(dimethylsiloxane) (PDMS) surface is described. The present method using PVA film as a sacrificial layer allowed successful immobilization of an intact PVC membrane using an ionic liquid-based dye on only the convex-shaped PDMS surface without any deformation or increase of the inhomogeneity. In addition, two different kinds of PVC membranes were successfully immobilized simultaneously toward multiplexed detection.