In this work, nickel oxide (NiO) nanostructures deposited by glancing angle deposition (GLAD) are fabricated to achieve highly specific catalytic electrooxidation of lactate, replacing the natural enzyme lactate oxidase for electrochemical detection in sweat. GLAD NiO electrodes exhibit high sensitivity (412 μA mM−1 cm−2), wide linear range (1–45 mM), low limit (3 μM), and excellent specificity artificial sweat samples. The unique microporous structure electrodes, combined with their surface...

In this work, we report the direct electrochemical oxidation of fentanyl using commercial screen-printed carbon electrodes (SPCEs) modified with carboxyl-functionalized nanofibers (fCNFs). CNFs have surface chemistry and reactivity similar to nanotubes (CNTs), yet they are easier produce a lower cost than CNTs. By monitoring current produced during fentanyl, variables such as fCNF loading, accumulation time, electrolyte pH, differential pulse voltammetry parameters were optimized. Under an...

A microchip structure etched on a glass substrate for packed column solid-phase extraction (SPE) and capillary electrochromatography (CEC) is described. 200 νm long, octadecylsilane (ODS) was secured using two different approaches: solvent lock or polymer entrapment. The former method utilized SPE while the latter approach applied CEC. In SPE, ODS chamber gave detection limit of 70 fM nonpolar BODIPY (493/503) dye when concentrated 3 min at an electroosmotic flow rate 4.14 nL/min, compared...

An interface design is presented that facilitates automated sample introduction into an electrokinetic microchip, without perturbing the liquids within microfluidic device. The utilizes flow channel with a volume resistance 0.54—4.1 × 106 times lower than of fluid manifold used for mixing, reaction, separation, and analysis. A channel, 300 μm deep, 1 mm wide 15—20 long, was etched in glass substrates to create (SIC) channels range 10—13 depth 36—275 width. Volume rates up mL/min were pumped...

Abstract Integration of a packed column onto microchip for performance capillary electrochromatography (CEC) is described. The quartz device incorporated cross‐injector, and double weir trapping design formation 1, 2 5 mm long CEC columns. Three fluorescent dyes were baseline‐resolved with plate numbers 330 (330 000 plates/m; height equivalent to theoretical plate, H = 3.0 μm) BODIPY 493/503, 360 (360 2.8 rhodamine 123 244 (244 4.1 acridine orange (AO) 500 V applied on 1 column. yielded ∼1.8...

Abstract We describe a microfluidic device in which integrated tryptic digestion, SPE, CE separation and electrospray ionization for MS are performed. The chip comprised of 10×30 μm channels CE, two serially connected 150 deep, 800 wide packed with 40 to 60 diameter beads, loaded either immobilized trypsin, reversed‐phase packing or both. On‐chip digestion cytochrome c using the trypsin bed showed complete consumption protein 3 min, contrast 2 h required conventional solution phase...

A molecularly imprinted polymer (MIP)-based electrochemical sensor featuring an electrochemically grafted para-phenylenediamine functional monomer on a reduced graphene oxide-gold nanoparticles composite modified screen printed electrode is reported. The morphology and properties of the sensing material were characterized with microscopy, spectroscopy techniques. number factors affecting performance MIP examined optimized. Under optimized condition, yielded homogenous naloxone binding sites...

The spread of infectious diseases poses a global threat to human health and the economy. Conventional laboratory-based pathogen detection analytical techniques are reliable, but labour time consuming. Decentralized, rapid classification devices essential boost biosecurity efforts can aid in advancement modern medicine. Here, we describe development an integrated digital microfluidic (DMF) electrochemical impedimetric sensor for on-site lipopolysaccharide (LPS), molecular signature...

Integrated sensing can be realized in a digital microfluidic (DMF) system not by adding components or materials to the DMF system, but judiciously removing portions of ground plane create microwave-resonant structures.

A molecularly imprinted sol-gel is reported for selective and sensitive electrochemical determination of the drug naloxone (NLX). The sensor was developed by combining molecular imprinting techniques electrochemically grafting sol solution onto a functionalized multiwall carbon nanotube modified indium-tin oxide (ITO) electrode. layer obtained from acid catalyzed hydrolysis condensation composed triethoxyphenylsilane (TEPS) tetraethoxysilane (TES). fabrication, structure properties sensing...

The integration of porous structures into microchannels is known to enable unique and useful separations both in electrophoresis chromatography. Etched pillars other nanostructures have received considerable interest recent years as a platform for creating with pores tailored specific applications. We present versatile method three-dimensionally sculptured nano- micro-structures PDMS microchannels. Glancing angle deposition was used fabricate that were subsequently embedded using sacrificial...

An extensive study of capillary flow fluids with various viscosities in straight and periodically constricted microchannels different surface wettability is presented. Capillary filling speed hydrophilic, less hydrophobic were experimentally monitored compared the Washburn theoretical model. For all liquids, a linear relationship was found between square propagation distance time, which expected for Newtonian fluids. Experimental results indicated slower velocity to prediction due...

Microchip-based bead-packed columns for electrochromatography are described several types of stationary phases. Chromatography 2 mm in length were used the separation proteins and peptides by size- ion-exchange modes separation, respectively. In size-exclusion electrochromatograpgy, FITC-IgG FITC-insulin baseline resolved less than 10 s, with efficiencies up to 139,000 plates/m FITC-insulin. strong cation-exchange electrochromatography, a mixture three fluorescently labeled was 40 400,000...

Both 6 and 8-channel integrated microfluidic sample pretreatment devices capable of performing "in space" fractionation, collection, preconcentration elution captured analytes via sheath flow assisted electrokinetic pumping are described. Coatings monolithic polymer beds were developed for the glass to provide cationic surface charge anodal electroosmotic delivery an electrospray emitter tip. A mixed ([2-(methacryloyloxy)ethyl] trimethylammonium chloride) (META) hydrophobic butyl...

Nickel oxide (NiO) thin films prepared by glancing angle deposition (GLAD) were investigated as electrodes for enzymatic electrochemical quantification of xanthine, a noted indicator meat freshness. The large surface area the macroporous GLAD NiO provided suitable scaffold to successfully immobilize enzyme xanthine oxidase (XO), and this XO immobilization was characterized cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy. XO-modified electrochemically oxidize with...

Herein, we describe a rapid and facile fabrication of electrochemical sensors utilizing two different toll-like receptor (TLR) proteins as biorecognition elements to detect bacterial pathogen associated molecular patterns (PAMPs).

Glancing angle deposition (GLAD) was used to fabricate nanostructured silicon (Si) thin films with highly controlled morphology for use in laser desorption/ionization mass spectrometry (DIOS-MS). Peptides, drugs and metabolites the range of 150-2500 Da were readily analyzed. The best performance obtained 500 nm thick deposited at a 85 degrees . Low background spectra attomole detection limits observed DIOS-MS various peptides. Films after three months dry storage ambient conditions produced...

We report on a facile method to stabilize colloidal self‐assembled (CSA) nanoparticles packed in microchannels for high speed size‐based separation of proteins. Silica nanoparticles, network microfluidic channels, were stabilized with methacrylate polymer prepared situ through photopolymerization. The entrapment conditions investigated minimize the effect matrix structure packing and properties CSA beds. SEM shows that links at specific sphere–sphere contact points, improving stability...