Polyaniline/Titania Nanotube-Based Biosensor Strip for Sensitive and Specific Electrochemical Detection of SARS-CoV-2.

This study showcases the creation of a biosensor strip designed for the rapid, precise, and highly sensitive electrochemical detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These biosensor strips were crafted by affixing a monoclonal antibody (mAb) specific to SARS-CoV-2 onto the surface of a commercially screen-printed carbon electrode (SPCE) modified with polyaniline-titania nanotubes (PANi-TNT). The transportable sensing device was constructed by pairing the mAb functionalized strip with a portable potentiostat wirelessly connected to either a Windows or Android device.

Water-Soluble Noble Metal Nanoparticle Catalysts Capped with Small Organic Molecules for Organic Transformations in Water.

This article recaps a variety of interesting catalytic studies based on solubilized and freely movable noble metal nanoparticle catalysts employed for organic reactions in either pure water or water-organic biphasic systems. Small organic ligand-capped metal nanoparticles are fundamentally attractive materials due to their enormous potential as a well-defined system that can provide spatial control near active catalytic sites. The nanoparticle catalysts are first grouped based on the synthetic method (direct reduction, phase transfer, and redispersion) and then again based on the type of reaction such as alkene hydrogenation, arene hydrogenation, nitroaromatic reduction, carbon-carbon coupling reactions, etc.

Hydrothermal-process-based direct extraction of polydisperse lignin microspheres from black liquor and their physicochemical characterization.

Lignin nano-/microstructures are widely employed for agricultural drug delivery and heavy metal removal from wastewater, and facile low-cost methods of their large-scale production are therefore highly sought after. Herein, uniform-morphology polydisperse lignin microspheres were directly extracted from black liquor by lowering its pH to <4 followed by hydrothermal treatment and featured several lignin-typical characteristics, e.g.

Generating Color from Polydisperse, Near Micron-Sized TiO Particles.

Single particle Mie calculations of near micron-sized TiO particles predict strong light scattering dominating the visible range that would give rise to a white appearance. We demonstrate that a polydisperse collection of these "white" particles can result in the generation of visible colors through ensemble scattering. The weighted averaging of the scattering over the particle size distribution modifies the sharp, multiple, high order scattering modes from individual particles into broad variations in the collective extinction.

Chemiluminescence determination of moxifloxacin in pharmaceutical and biological samples based on its enhancing effect of the luminol-ferricyanide system using a microfluidic chip.

A sensitive determination of a synthetic fluoroquinolone antibacterial agent, moxifloxacin (MOX), by an enhanced chemiluminescence (CL) method using a microfluidic chip is described. The microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS). The fabricated PDMS microfluidic chip had three-inlet microchannels for introducing the sample, chemiluminescent reagent and oxidant, and a 500 µm wide, 250 µm deep and 82 mm long microchannel.

Chemiluminescence microfluidic system of gold nanoparticles enhanced luminol-silver nitrate for the determination of vitamin B12.

A rapid and sensitive chemiluminescence (CL) system coupled with a microfluidic chip has been presented to determine vitamin B12 (VB12) based on the reaction of luminol and silver nitrate (AgNO(3)) in the presence of gold nanoparticles (AuNPs). A microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS) having four inlets and one outlet with a 200 μm wide, 250 μm deep, and 100 mm long microchannel. Ag(+) was used as a chemiluminogenic oxidant in this CL reaction which oxidized luminol to produce strong CL signal in the presence of AuNPs.

Enzymeless determination of total sugar by luminol-tetrachloroaurate chemiluminescence on chip to analyze food samples.

Chemiluminescence (CL) emission from luminol-tetrachloroaurate ([AuCl(4)](-)) system studied in presence of monosaccharide sugars such as glucose and fructose was investigated on a microfluidic chip fabricated by the soft lithography technique. CL emission from the luminol-[AuCl(4)](-) system at 430 nm was intensified remarkably by the catalytic activity of glucose and fructose at room temperature. Under optimized conditions, the CL emission intensity of the system was found to be linearly related to the concentration of the sugars.

Enhanced luminescence of lanthanide complexes by silver nanoparticles for ciprofloxacin determination.

We present the enhancement of luminescence of europium complex, Eu(3+)-ciprofloxacin (CIP), in the presence of silver nanoparticles (Ag NPs) for the CIP determination. The increment of the luminescence intensity of the Eu(3+)-CIP complex with Ag NPs was obtained due to the transfer of resonance energy to the fluorophores through the interaction of the excited-state fluorophores and surface plasmon electron in the metal nano surface. The luminescence intensity of Eu3+ was enhanced by complexation with CIP at 614 nm after excitation at 373 nm corresponding to the 5D0-7F2 transitions of Eu3+ ion.

Silver nanoparticles enhanced luminescence of terbium complex in solution for L-dopa determination.

Luminescent properties of a terbium (Tb3+)-L-3, 4-dihydroxyphenylalanine (L-dopa) complex by binding to colloidal silver nanoparticles (Ag NPs) have been presented. Luminescence intensity of the L-dopa complex was dramatically enhanced about 6-7 times by introducing Ag NPs. The Ag NPs concentration on the luminescent intensity was regarded as a main factor that balancing between an enhancing and a quenching effect of the Ag NPs.

Silver nanoparticle-enhanced chemiluminescence method for determining naproxen based on europium(III)-sensitized Ce(IV)-Na2S2O4 reaction.

A simple and sensitive chemiluminescence (CL) method coupled with flow-injection technique is proposed to determine naproxen (NAP). The method is based upon the enhancement of the weak CL signal arising from the reaction of Ce(IV) and Na(2)S(2)O(4) with Eu(3+) to form the Eu(3+)-Ce(IV)-Na(2)S(2)O(4) system. The CL intensity was significantly increased by the introduction of NAP into this system in the presence of silver nanoparticles (Ag NPs).

Spectrofluorimetric study of the interaction between europium(III) and moxifloxacin in micellar solution and its analytical application.

A sensitive spectrofluorimetric method has been developed for the determination of moxifloxacin (MOX) using europium(III)-MOX complex as a fluorescence probe in the presence of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS). The fluorescence (FL) intensity of Eu(3+) was enhanced by complexation with MOX at 614 nm after excitation at 373 nm. The FL intensity of the Eu(3+)-MOX complex was significantly intensified in the presence of SDBS.

A terbium-sensitized spectrofluorimetric method for determination of catecholamines in a serum sample with micelle medium.

A terbium-sensitized spectrofluorimetric method has been developed for determination of catecholamines such as norepinephrine (NE), epinephrine (EP) and dopamine (DA), using sodium dodecyl benzene sulphonate (SDBS). Fluorescence sensitization of terbium ions (Tb(3+) ) by complexation with catecholamines in the presence of SDBS was observed. The fluorescence intensities of the Tb(3+) -catecholamine complexes were highly enhanced by introducing SDBS with an emission maximum at 545 nm after excitation at 290 nm.

Ultrasensitive study of gatifloxacin based on its enhancing effect on the cerium (IV)-sodium hyposulfite chemiluminescence reaction in a micellar medium.

A sensitive and rapid flow-injection chemiluminescence (CL) method has been developed for the determination of gatifloxacin in pharmaceutical preparations and biological samples. The method is based on the enhancing effect of gatifloxacin on CL emission generated by the interaction of Ce (IV) in sulphuric acid and sodium hyposulphite (Na(2)S(2)O(4)) sensitized by sodium dodecyl benzene sulfonate (SDBS). Strong CL emission was observed when gatifloxacin was injected into the Ce (IV) in sulphuric acid and Na(2)S(2)O(4) solution incorporated with SDBS in a flow-cell.