1,720,973 research outputs found
IrOx_RuOX_pHSensor_Dataset
No full textData set to accompany the publication: Iridium and Ruthenium oxide miniature pH sensors: long-term performance published in Sensors and Actuators B: Chemical. DOI: 10.1016/j.snb.2019.126779</span
Shaped apertures enhance the stability of suspended lipid bilayers
No full textA biological membrane not only forms a protective outer boundary for cells and organelles but also houses ion channels that are attractive drug targets. The characterisation of membrane-embedded ion channels hence is of prime importance, but in vivo studies have been hindered by the complexity of the natural membranes. Lipid bilayers suspended in apertures have provided a simple and controlled model membrane system for ion channel studies, but short lifetimes and poor mechanical stability of suspended bilayers have limited the experimental throughput of bilayer electrophysiology experiments. Although suspended bilayers are more stable when smaller apertures are used, ion channel incorporation through vesicle fusion with the suspended bilayer becomes increasingly difficult. In this project, in an alternative bilayer stabilization approach, shaped apertures with tapered sidewalls have been fabricated with serial two-photon laser lithography and high-throughput grayscale lithography in photoresist. Bilayers formed at the 2µm thin tip of the shaped apertures, either with the painting or the folding method, displayed drastically increased lifetimes, typically >20 hours, and mechanical stability, being able to withstand extensive perturbation of the buffer solution, as compared to the control shapes. Single-channel electrical recordings of the peptide Alamethicin, water soluble protein ?-Hemolysin and of the proteoliposome-delivered potassium and sodium channels KcsA, hERG and NavSp pore domains demonstrate channel conductance with low noise, made possible by the small capacitance of the 50µm thick resist septum, which is only thinned around the aperture, and unimpeded proteoliposome fusion, enabled by the large aperture diameter of 80µm. Optically accessible horizontal bilayers in shaped apertures were developed to visualize suspended bilayers and incorporated ion channels. It is anticipated that these shaped apertures with micrometer edge thickness can substantially enhance the throughput of channel characterisation by bilayer lipid membrane electrophysiology, especially in combination with automated parallel bilayer platforms
Fast and sensitive isothermal DNA assay using micro-bead dielectrophoresis for detection of anti-microbial resistance genes
No full textAntimicrobial resistant pathogens are a growing worldwide threat to human health. This study proposes a novel method for rapid and sensitive detection of antimicrobial resistance (AMR) genes, specifically blaCTX-M-15 which encodes for the enzyme that offers resistance to extended spectrum -lactam antibiotics. The method combines isothermal DNA amplification by recombinase polymerase amplification (RPA), with microbead dielectrophoresis (DEP)-based DNA detection. The amplicon of RPA is attached to dielectric microbeads, and the amount of amplicon determined by dielectrophoretic impedance measurement (DEPIM) of the microbeads. Amplicon-labeled microbeads were prepared by two-step and one-step labeling. A purified recombinant plasmid containing blaCTX-M-15 and genomic DNA (with plasmid) extracted from AMR bacteria (Escherichia coli NCTC 13441) were used as target samples. A one-step method in which RPA and DNA immobilization on the microbeads are carried out simultaneously, has a detection limit of 2 copies/reaction for the pure plasmid and 50 copies/reaction for genomic DNA. The assays are quantitative with a dynamic range up to 105 copies/reaction, with a total detection time of 26 min. Both methods are easy, rapid, and unlike lateral flow detection are quantitative.<br/
Dataset for Fast and sensitive isothermal DNA assay using micro-bead dielectrophoresis for detection of anti-microbial resistance genes
No full textDataset supports:
Nakano, M. I., Kalsi, S., & Morgan, H. (2018). Fast and sensitive isothermal DNA assay using micro-bead dielectrophoresis for detection of anti-microbial resistance genes. Biosensors & Bioelectronics.
Antimicrobial resistant pathogens are a growing worldwide threat to human health. This study proposes a novel method for rapid and sensitive detection of antimicrobial resistance (AMR) genes, specifically blaCTX-M-15 which encodes for the enzyme that offers resistance to extended spectrum β-lactam antibiotics. The method combines isothermal DNA amplification by recombinase polymerase amplification (RPA), with microbead dielectrophoresis (DEP)-based DNA detection. The amplicon of RPA is attached to dielectric microbeads, and the amount of amplicon determined by dielectrophoretic impedance measurement (DEPIM) of the microbeads. Amplicon-labeled microbeads were prepared by two-step and one-step labeling. A purified recombinant plasmid containing blaCTX-M-15 and genomic DNA (with plasmid) extracted from AMR bacteria (Escherichia coli NCTC 13441) were used as target samples. A one-step method in which RPA and DNA immobilization on the microbeads are carried out simultaneously, has a detection limit of 2 copies/reaction for the pure plasmid and 50 copies/reaction for genomic DNA. The assays are quantitative with a dynamic range up to 105 copies/reaction, with a total detection time of 26 min. Both methods are easy, rapid, and unlike lateral flow detection are quantitative.
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Metal oxide sensors for long term pH monitoring
No full textThe determination of pH, a measure of concentration of hydrogen ions in a solution, is an important task in analytical chemistry since various biological and chemical reaction mechanisms are pH dependent. While the conventional glass type electrodes are widely used for their high accuracy; they are not amenable to miniaturization, and suffer from sluggish response [1], [2], [3]. Various solid-state metal oxide pH sensing electrodes, chiefly iridium oxide and ruthenium oxide (RuOx), have been investigated as an alternate. RuOx exhibits several unique advantages over other metal oxides such as thermal stability, excellent corrosion resistance, low hysteresis, low cost and high sensitivity [4]. In this work, we developed and investigated the long-term performance of the RuOx films on platinum electrode. The sensors exhibited near-Nernstian response at 55 mV/pH and long-term stability of over 4 weeks
Programmable digital microfluidic assay for simultaneous detection of multiple anti-microbial resistance genes
No full textThe rapid emergence of antimicrobial resistant bacteria requires the development of new diagnostic tests. Nucleic acid based assay determine antimicrobial susceptibility by detecting genes that encode for the resistance. In this study, we demonstrate rapid and simultaneous detection of three genes that confer resistance in bacteria to extended spectrum β-lactam and carbapenem antibiotics; CTX-M-15, KPC and NDM-1. The assay uses isothermal DNA amplification (Recombinase Polymerase Amplification, RPA) implemented on a programmable digital microfluidics (DMF) platform. Automated dispensing protocols are used to simultaneously manipulate 45 droplets of nL volume containing sample DNA, reagents and controls. The droplets are processed and mixed under electronic control on the DMF devices with positive amplification measured by fluorescence. The assay is fast, has two orders of magnitude improved sensitivity compared with a benchtop assay. </span
Dataset for Sample pre-concentration on a digital microfluidic platform for rapid AMR detection in urine
No full textAssigned DOI: 10.5258/SOTON/D0731
Data set for figures in:
Kalsi, S. et al (2018). Sample pre-concentration on a digital microfluidic platform for rapid AMR detection in urine. Lab on a Chip., DOI: https://doi.org/10.1039/C8LC01249K</span
Sample pre-concentration on a digital microfluidic platform for rapid AMR detection in urine
No full textThere is a growing need for rapid diagnostic methods to support stewardship of antibiotics. We describe an analytical platform for sample concentration to detect antimicrobial resistance (AMR) genes directly from human urine for the diagnosis of Urinary Tract Infections (UTIs) that are resistant to antibiotics. A sample-processing unit concentrates plasmid DNA directly from urine using magnetic beads, followed by isothermal amplification of target genes. The sample pre-concentration unit interfaces with a digital microfluidic platform (DMF) and scales the sample volume by 500-fold, pre-concentrating DNA from 1mL into a 2L droplet for downstream processing. Tests with a clinical strain of Klebsiella pneumoniae (NCTC 13443), spiked into human urine demonstrated a limit of detection of 104 cfu/mL and a “sample to answer” in approximately 30 minutes
From smartphones to diagnostics: Low cost electronics for programmable digital microfluidics and sensing
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