Nanostructured microelectrodes (NMEs) are three-dimensional electrodes that have superb sensitivity for electroanalysis. Here we report the integration of NMEs with the versatile fluid-handling system digital microfluidics (DMF), for eventual application to distributed diagnostics outside of the laboratory. In the new methods reported here, indium tin oxide DMF top plates were modified to include Au NMEs as well as counter and pseudoreference electrodes. The new system was observed to outperform planar sensing electrodes of the type that are typically integrated with DMF. A rubella virus (RV) IgG immunoassay was developed to evaluate the diagnostic potential for the new system, relying on magnetic microparticles coated with RV particles and analysis by differential pulse voltammetry. The limit of detection of the assay (0.07 IU mL(-1)) was >100× below the World Health Organization defined cut-off for rubella immunity. The sensitivity of the integrated device and its small size suggest future utility for distributed diagnostics.
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http://dx.doi.org/10.1039/c5lc00660k | DOI Listing |
ACS Nano
December 2024
Department of Electrical and Computer Engineering, Montana State University, Bozeman, Montana 59717, United States.
Nanomagnetic forces deliver precise mechanical cues to biological systems through the remote pulling of magnetic nanoparticles under a permanent magnetic field. Cortical neurons respond to nanomagnetic forces with cytosolic calcium influx and event rate shifts. However, the underlying consequences of nanomagnetic force modulation on cortical neurons remain to be elucidated.
View Article and Find Full Text PDFLangmuir
December 2024
Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Prof. Sobouti Boulevard, 45137-66731, Zanjan, Iran.
In modern analytical chemistry, one of the primary goals is to develop miniaturized, easy-to-use sensing tools, particularly those with multitasking capabilities. In this work, we designed a mini-voltammetric cell that integrates a modified Au microelectrode (Au/Au NPs as the working electrode) and an Ag/AgCl reference electrode installed within a micropipette tip. This combined tool not only enables portable and on-site microvolume sampling─requiring only a microvolume (around 20-40 μL) or a single droplet─but also facilitates direct micro-electroanalysis in a short time.
View Article and Find Full Text PDFAnal Methods
November 2024
Georgia Institute of Technology, 315 Ferst Dr NW, Atlanta, GA 30332, USA.
Enzyme-linked immunosorbent assays are commonly used for clinical biomarker detection. However, they remain resource-intensive and difficult to scale globally. Here we present a miniaturized direct electronic biosensing modality which generates a simple and sensitive, quantitative, resistive readout of analyte binding in immunoassays.
View Article and Find Full Text PDFAnalyst
November 2024
School of Electrical & Electronic Engineering, Yonsei University, Seoul, 03722, South Korea.
Faraday Discuss
October 2024
Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee, 11 89081 Ulm, Germany.
Platinum-black (Pt-B) has been demonstrated to be an excellent electrocatalytic material for the electrochemical oxidation of hydrogen peroxide (HO). As Pt-B films can be deposited electrochemically, micro- and nano-sized conductive transducers can be modified with Pt-B. Here, we present the potential of Pt-B micro- and sub-micro-sized sensors for the detection and quantification of hydrogen (H) in solution.
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