Synthesis of magnetic FeO/graphene aerogel for the removal of 2,4-dichlorophenoxyacetic acid herbicide from water.

Graphene-based aerogels are among the lightest materials in the world and have been extensively studied for environmental remediation. In this work, an FeO/graphene aerogel material was synthesized using the co-precipitation method. The prepared material was characterized using X-ray diffraction (XRD), scanning electron microscopy/X-ray energy dispersive spectroscopy (FESEM/EDX), infrared spectroscopy (FT-IR), and vibration sample magnetization (VSM).

Simple and Label-Free Detection of Carboxylesterase and Its Inhibitors Using a Liquid Crystal Droplet Sensing Platform.

In this study, we developed a liquid crystal (LC) droplet-based sensing platform for the detection of carboxylesterase (CES) and its inhibitors. The LC droplet patterns in contact with myristoylcholine chloride (Myr) exhibited dark cross appearances, corresponding to homeotropic anchoring of the LCs at the aqueous/LC interface. However, in the presence of CES, Myr was hydrolyzed; therefore, the optical images of the LC patterns changed to bright fan-shaped textures, corresponding to a planar orientation of LCs at the interface.

Ultrasensitive colorimetric detection of amoxicillin based on Tris-HCl-induced aggregation of gold nanoparticles.

An ultrasensitive colorimetric aptasensor for the detection of amoxicillin (AMO) based on the Tris-HCl buffer-induced aggregation of gold nanoparticles (AuNPs) was developed. The AuNPs were aggregated by the addition of Tris-HCl buffer. The adsorption of the aptamer on the AuNP surface increased its negative charge density, leading to the enhancement of the electrostatic repulsion between the nanoparticles, thus protecting AuNPs from aggregation in the Tris-HCl buffer.

A Simple and Ultrasensitive Colorimetric Biosensor for Anatoxin-a Based on Aptamer and Gold Nanoparticles.

Here, we designed a simple, rapid, and ultrasensitive colorimetric aptasensor for detecting anatoxin-a (ATX-a). The sensor employs a DNA aptamer as the sensing element and gold nanoparticles (AuNPs) as probes. Adsorption of the aptamer onto the AuNP surface can protect AuNPs from aggregation in NaCl solution, thus maintaining their dispersion state.

A Label-Free Liquid Crystal Biosensor Based on Specific DNA Aptamer Probes for Sensitive Detection of Amoxicillin Antibiotic.

We developed a liquid crystal (LC) aptamer biosensor for the sensitive detection of amoxicillin (AMX). The AMX aptamer was immobilized onto the surface of a glass slide modified with a mixed self-assembled layer of dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) and (3-aminopropyl) triethoxysilane (APTES). The long alkyl chains of DMOAP maintained the LC molecules in a homeotropic orientation and induced a dark optical appearance under a polarized light microscope (POM).

A Cationic Surfactant-Decorated Liquid Crystal-Based Aptasensor for Label-Free Detection of Malathion Pesticides in Environmental Samples.

We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) solution due to the formation of a self-assembled CTAB monolayer at the aqueous/LC interface, which induced the homeotropic orientation of LCs. With the addition of malathion aptamer, the homeotropic orientation of LCs changed to a planar one due to the interactions between CTAB and the aptamer, resulting in a bright optical image.

An acetylcholinesterase-based biosensor for the detection of pesticides using liquid crystals confined in microcapillaries.

Here, we demonstrate a capillary-sensing platform based on liquid crystals (LCs) confined in microcapillaries for simple and sensitive detection of acetylcholinesterase (AChE) and its inhibitors. LC droplets were formed through sequential injection of LCs and an aqueous solution into trichloro(octyl)silane (OTS)-treated microcapillaries. When the confined LC droplets make contact with a cationic surfactant solution, myristoylcholine chloride (Myr), the formation of a Myr monolayer at the aqueous/LC interface induces a horizontal orientation of the LCs at the interface along the microcapillary, producing an optical LC droplet texture of a four-petal shape.

Label-free liquid crystal-based biosensor for detection of dopamine using DNA aptamer as a recognition probe.

We present a label-free liquid crystal-based biosensor for the detection of dopamine (DA) in aqueous solutions using dopamine-binding aptamers (DBA) as recognition elements. In this system, the dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) self-assembled monolayers immobilized on glass slides support the long alkyl chains that keep the liquid crystal (LC) molecules in a homeotropic orientation. Glutaraldehyde (GA) is used as a cross-linker to immobilize DBA onto the surface of glass slides.

Synthesis and Irreversible Thermochromic Sensor Applications of Manganese Violet.

An irreversible thermochromic material based on manganese violet (MnNH₄P₂O₇) is synthesized. The crystal phase, chemical composition, and morphology of the synthesized material are analyzed using X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, and Fourier-transform infrared spectroscopy. The absorption spectra of the synthesized material are obtained using a UV-Vis spectrometer, and the thermochromism exhibited by the powdered samples at high temperatures is also investigated.

Synthesis and Thermochromic Properties of Cr-Doped Al₂O₃ for a Reversible Thermochromic Sensor.

An inorganic thermochromic material based on Cr-doped Al₂O₃ is synthesized using a solid-state method. The crystal structure, chemical composition, and morphology of the synthesized material are analyzed using X-ray diffraction, scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer, and Fourier transform infrared (FT-IR) spectroscopy. The color performances of the synthesized material are analyzed using a UV-VIS spectrometer.

Hydrogel Encapsulation of Cells in Core-Shell Microcapsules for Cell Delivery.

A newly designed 3D core-shell microcapsule structure composed of a cell-containing liquid core and an alginate hydrogel shell is fabricated using a coaxial dual-nozzle electrospinning system. Spherical alginate microcapsules are successfully generated with a core-shell structure and less than 300 μm in average diameter using this system. The thickness of the core and shell can be easily controlled by manipulating the core and shell flow rates.