A droplet-based electrochemical digital magnetofluidics system has been developed. The system relies on the magnetic movement, in air, of different aqueous microdroplets containing magnetic microparticles--serving as the 'sample', 'blank', 'wash' and 'reagent' solutions--into and out of a three-electrode assembly. The movement of all droplets was controlled using the magnetic fields generated by three separate external magnets positioned below the superhydrophobic surface. Square-wave voltammetry was used for rapid measurements of dopamine in multiple successive microdrops with minimal cross talk. The ability of the droplet-based electrochemical microfluidic system to manipulate microliter solutions was also illustrated in bioassays of glucose, involving the merging of enzyme (GOx) and substrate droplets, followed by chronoamperometric measurements of the hydrogen peroxide product in the merged droplet. Variables of the new electrochemical digital magnetomicrofluidic technique were examined and optimized. The new droplet-based electrochemical microfluidic system offers a promising platform for automated clinical diagnostics and drug discovery.
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http://dx.doi.org/10.1039/b617631c | DOI Listing |
The next-generation of energy devices rely on advanced catalytic materials, especially electrocatalytic nanoparticles (NPs), to achieve the performance and cost required to reshape the energy landscape towards a more sustainable and cleaner future. It has become imperative to maximize the performance of the catalyst, both through improvement of the intrinsic activity of the NP, and by ensuring all particles are performing at the level of their capability. This requires not just a structure-function understanding of the catalytic material, but also an understanding of how the catalyst performance is impacted by its environment (substrate, ligand, ).
View Article and Find Full Text PDFSensors (Basel)
January 2024
Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany.
Gallium liquid metals (LMs) like Galinstan and eutectic Gallium-Indium (EGaIn) have seen increasing applications in heavy metal ion (HMI) sensing, because of their ability to amalgamate with HMIs like lead, their high hydrogen potential, and their stable electrochemical window. Furthermore, coating LM droplets with nanopowders of tungsten oxide (WO) has shown enhancement in HMI sensing owing to intense electrical fields at the nanopowder-liquid-metal interface. However, most LM HMI sensors are droplet based, which show limitations in scalability and the homogeneity of the surface.
View Article and Find Full Text PDFFront Microbiol
November 2023
Research Center of Molecular Diagnostics and Sequencing, Axbio Biotechnology (Shenzhen) Co., Ltd., Shenzhen, China.
In Phi29-α-hemolysin (α-HL) nanopore sequencing systems, a strong electrochemical signal is dependent on a high concentration of salt. However, high salt concentrations adversely affect polymerase activity. Sequencing by synthesis (SBS) requires the use of phi29 polymerase without exonuclease activity to prevent the degradation of modified nucleotide tags; however, the lack of exonuclease activity also affects polymerase processivity.
View Article and Find Full Text PDFNat Methods
September 2023
Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.
Single-particle cryogenic electron microscopy (cryo-EM) allows reconstruction of high-resolution structures of proteins in different conformations. Protein function often involves transient functional conformations, which can be resolved using time-resolved cryo-EM (trEM). In trEM, reactions are arrested after a defined delay time by rapid vitrification of protein solution on the EM grid.
View Article and Find Full Text PDFJ Phys Chem Lett
May 2023
Electrochemical Technology Centre, Department of Chemistry, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
A deep understanding of the properties of semiconductor films at the micro-/nanoscale level is fundamental toward designing effective photoelectrocatalysts. Here, we integrated spatially resolved optical spectroscopy (SR-OS) with scanning photoelectrochemical microscopy (SPECM) to collect UV/vis spectra and quantify photocurrents of localized sites on a nanostructured BiVO thin film. Direct measurement of absorbance allowed for the determination of band gap energy at each location.
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