Publications
119 results found
Rawson T, o'hare D, Herrero P, et al., 2018, Delivering precision antimicrobial therapy through closed-loop control systems, Journal of Antimicrobial Chemotherapy, Vol: 73, Pages: 835-843, ISSN: 0305-7453
Sub-optimal exposure to antimicrobial therapy is associated with poor patient outcomes and the development of antimicrobial resistance. Mechanisms for optimizing the concentration of a drug within the individual patient are under development. However, several barriers remain in realizing true individualization of therapy. These include problems with plasma drug sampling, availability of appropriate assays, and current mechanisms for dose adjustment. Biosensor technology offers a means of providing real-time monitoring of antimicrobials in a minimally invasive fashion. We report the potential for using microneedle biosensor technology as part of closed-loop control systems for the optimization of antimicrobial therapy in individual patients.
Bell CG, Seelanan P, O'Hare D, 2017, Microelectrode generator-collector systems for electrolytic titration: theoretical and practical considerations, ANALYST, Vol: 142, Pages: 4048-4057, ISSN: 0003-2654
Rawson TM, Sharma S, Georgiou P, et al., 2017, Towards a minimally invasive device for beta-lactam monitoring in humans, Electrochemistry Communications, Vol: 82, Pages: 1-5, ISSN: 1388-2481
Antimicrobial resistance is a leading patient safety issue. There is a need to develop novel mechanisms for monitoring and subsequently improving the precision of how we use antibiotics. A surface modified microneedle array was developed for monitoring beta-lactam antibiotic levels in human interstitial fluid. The sensor was fabricated by anodically electrodepositing iridium oxide (AEIROF) onto a platinum surface on the microneedle followed by fixation of beta-lactamase enzyme within a hydrogel. Calibration of the sensor was performed to penicillin-G in buffer solution (PBS) and artificial interstitial fluid (ISF). Further calibration of a platinum disc electrode was undertaken using amoxicillin and ceftriaxone. Open-circuit potentials were performed and data analysed using the Hill equation and log(concentration [M]) plots. The microneedle sensor demonstrated high reproducibility between penicillin-G runs in PBS with mean Km (± 1SD) = 0.0044 ± 0.0013 M and mean slope function of log(concentration plots) 29 ± 1.80 mV/decade (r2 = 0.933). Response was reproducible after 28 days storage at 4 °C. In artificial ISF, the sensors response was Km (± 1SD) = 0.0077 ± 0.0187 M and a slope function of 34 ± 1.85 mv/decade (r2 = 0.995). Our results suggest that microneedle array based beta-lactam sensing may be a future application of this AEIROF based enzymatic sensor.
Zhexembekova A, Akhmetova N, Molkenova A, et al., 2017, Thiol-modified activated carbon material for sensor technology, 4th International Conference on Nanomaterials and Advanced Energy Storage Systems (INESS), Publisher: ELSEVIER SCIENCE BV, Pages: 4599-4602, ISSN: 2214-7853
Gandhi SI, Boutelle M, O'Hare D, 2016, A novel electrolytic titrator design - Coating platinum cathodes with an electron sink using Nafion (R) and hexaammineruthenium (III), ELECTROCHEMISTRY COMMUNICATIONS, Vol: 73, Pages: 50-54, ISSN: 1388-2481
Wilson RE, Stoianov I, O'Hare D, 2016, Biofouling and in situ electrochemical cleaning of a boron-doped diamond free chlorine sensor, Electrochemistry Communications, Vol: 71, Pages: 79-83, ISSN: 1873-1902
Biofouling presents a significant obstacle to the long-term use of electrochemical sensors in complex media. Drinking water biofilms reduce performance of sensors by insulating electrode surfaces by inter alia inhibiting mass transport. Boron-doped diamond (BDD) electrodes are relatively resistant to biofouling and inert at high potentials. These qualities can be exploited to create a drinking water quality sensor that resists biofouling to meet performance criteria for longer, and to enable electrochemical cleaning of the sensor surface in situ using high potentials without disconnecting or disassembling the sensor.A purpose-built BDD wall-jet sensor was compared with a glassy carbon (GC) sensor in ability to determine free chlorine, detect biofilm and remove biofilm in situ. It was found that the BDD produced accurate and reliable readings with a 4.86% standard error and a LOD of 0.18 ppm. The BDD could be electrochemically cleaned in situ whereas this was less successful with the GC electrode. The BDD electrode could also detect electroactive pyocyanin, secreted in the biofilm of the drinking water biofilm indicator organism Pseudomonas aeruginosa, potentially enabling biofouling and non-biological fouling such as scaling to be distinguished. Observed changes in flow sensitivity and current-voltage curves that correspond to fouling provide multiple fouling detection methods, resulting in an accurate, sensitive, water quality sensor that can be cleaned without disassembly or replacement of parts and can identify when cleaning is required.
Lee M-H, O'Hare D, Guo H-Z, et al., 2016, Electrochemical sensing of urinary progesterone with molecularly imprinted poly(aniline-co-metanilic acid)s, Journal of Materials Chemistry B, Vol: 4, Pages: 3782-3787, ISSN: 2050-7518
In this work, progesterone is imprinted into poly(aniline-co-metanilic acid) on the working electrode of an electrochemical sensing chip. This sensing chip was used directly to optimize the composition of the imprinting polymer. Poly(aniline-co-metanilic acid) deposited from a 1 : 3 molar ratio of aniline (ANI) : m-aminobenzenesulfonic acid (MSAN) had an imprinting effectiveness which led to a four-fold greater electrochemical response than pure polyaniline. The electrochemical sensing of progesterone had a limit of detection (LOD) less than 1.0 pg mL−1, and the direct electrochemical response was very weak even at high interference concentrations. Results from potential interferents (urea, testosterone, creatinine and 17-β estradiol) are reported. The progesterone levels that were measured in a random urine analysis were compared with those obtained using a commercial ARCHITECT system, and the accuracy of the progesterone concentration was 89.0 ± 5.3% at a concentration of 0.64–5.27 ng mL−1.
Ng SR, Pang H, Chen P, et al., 2015, A Novel Electroactive Polymer for pH-independent Oxygen Sensing, ELECTROANALYSIS, Vol: 27, Pages: 2745-2752, ISSN: 1040-0397
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- Citations: 3
Ng S, O'Hare D, 2015, An iridium oxide microelectrode for monitoring acute local pH changes of endothelial cells, The Analyst, Vol: 140, Pages: 4224-4231, ISSN: 0003-2654
pH sensors were fabricated by anodically electrodepositing iridium oxide films (AEIROFs) onto microelectrodes on chips and coated with poly(ethyleneimine) (PEI) for mechanical stability. These demonstrate super-Nernstian response to pH from pH 4.0 to 7.7 in chloride-free phosphate buffer. The surface of the chip was coated with fibronectin for the attachment of porcine aortic endothelial cells (PAECs). The working capability of the pH sensor for monitoring acute local pH changes was investigated by stimulating the PAECs with thrombin. Our results show that thrombin induced acute extracellular acidification of PAECs and dissolution of fibronectin, causing the local pH to decrease. The use of PD98059, a mitogen-activated protein kinase (MAPK) inhibitor, reduced extracellular acidification and an increase in local pH was observed. This study shows that our pH sensors can facilitate the investigation of acute cellular responses to stimulation by monitoring the real-time, local pH changes of cells attached to the sensors.
Huang C-Y, O'Hare D, Chao I-J, et al., 2015, Integrated potentiostat for electrochemical sensing of urinary 3-hydroxyanthranilic acid with molecularly imprinted poly (ethylene-<i>co</i>-vinyl alcohol), BIOSENSORS & BIOELECTRONICS, Vol: 67, Pages: 208-213, ISSN: 0956-5663
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- Citations: 25
Leow PL, Chee PS, Patel BA, et al., 2015, A study of the in-column detection performance for chromatography separation, Microfluidics and Nanofluidics, Vol: 19, Pages: 343-349, ISSN: 1613-4990
This paper studies the in-column detection performance for chromatography separation. Numerical modeling was performed to investigate the detection efficiency of the electrodes that are suspended within a packed chromatography column. The results show that the density of the silica beads packed within the channel does not hinder the detection ability of the electrode. The findings have been further validated with experimental works. An 8 in-column electrode array provides the full separation progress traces of the five neurotransmitters and metabolites (adrenalin, dopamine, DOPAC, serotonin and 5-HIAA) within the column. From the in-column detection, better peak resolutions are developed though the separation column as compared to the conventional post-column detection. The whole progress of the separation shows that good separation (R s > 1) can be obtained at E5 (28.7 mm from column inlet), whereas baseline separation could be obtained at E8 (last in-column electrode) with R s ≥ 1.5 within 60 min. The presented results suggest that the packing materials within the column do not obstruct the efficiency of the electrodes but able to produce a good baseline separation detection as compared to conventional post-column detection.
Lee M-H, O'Hare D, Chen Y-L, et al., 2014, Molecularly imprinted electrochemical sensing of urinary melatonin in a microfluidic system, BIOMICROFLUIDICS, Vol: 8, ISSN: 1932-1058
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- Citations: 8
Kim J-Y, Chang S-I, deMello AJ, et al., 2014, Integration of monolithic porous polymer with droplet-based microfluidics on a chip for nano/picoliter volume sample analysis., Nano Converg, Vol: 1, ISSN: 2196-5404
In this paper, a porous polymer nanostructure has been integrated with droplet-based microfluidics in a single planar format. Monolithic porous polymer (MPP) was formed selectively within a microfluidic channel. The resulting analyte bands were sequentially comartmentalised into droplets. This device reduces band broadening and the effects of post-column dead volume by the combination of the two techniques. Moreover it offers the precise control of nano/picoliter volume samples.
Trouillon R, Williamson ED, Saint RJ, et al., 2012, Electrochemical detection of the binding of <i>Bacillus anthracis</i> protective antigen (PA) to the membrane receptor on macrophages through release of nitric oxide, BIOSENSORS & BIOELECTRONICS, Vol: 38, Pages: 138-144, ISSN: 0956-5663
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- Citations: 13
Bell CG, Anastassiou CA, O'Hare D, et al., 2012, Theoretical treatment of high-frequency, large-amplitude ac voltammetry applied to ideal surface-confined redox systems, ELECTROCHIMICA ACTA, Vol: 64, Pages: 71-80, ISSN: 0013-4686
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- Citations: 3
Kim J-Y, Cho S-W, Kang D-K, et al., 2012, Lab-chip HPLC with integrated droplet-based microfluidics for separation and high frequency compartmentalisation, CHEMICAL COMMUNICATIONS, Vol: 48, Pages: 9144-9146, ISSN: 1359-7345
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- Citations: 19
Trouillon R, O'Hare D, Chang S-I, 2011, An electrochemical functional assay for the sensing of nitric oxide release induced by angiogenic factors, BMB REPORTS, Vol: 44, Pages: 699-704, ISSN: 1976-6696
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- Citations: 4
Yeatman EM, O'Hare D, Dobson C, et al., 2011, Approaches to self-powered biochemical sensors for in-vivo applications
The requirement for electrical power is a major limitation in the development of biosensors for in-body applications. This paper considers motion powered energy harvesting devices for in-body use, showing that power levels are unlikely to exceed a few microwatts for devices of acceptable size. As a low power sensor, we are developing pH detectors based on metal-metal oxide electrodes, such as iridium oxide. The power requirement of these devices is considered, including signal conditioning, storage and transmission. A hybrid powering scheme of energy harvesting and wireless power delivery for data transmission is proposed.
Bell CG, Anastassiou CA, O'Hare D, et al., 2011, Theory of large-amplitude sinusoidal voltammetry for reversible redox reactions, Electrochimica Acta
Bell CG, Anastassiou CA, O'Hare D, et al., 2011, Theory of high frequency, large-amplitude sinusoidal voltammetry for ideal surface-confined redox systems, Electrochimica Acta
Patel BA, Rogers M, Wieder T, et al., 2011, ATP microelectrode biosensor for stable long-term <i>in vitro</i> monitoring from gastrointestinal tissue, BIOSENSORS & BIOELECTRONICS, Vol: 26, Pages: 2890-2896, ISSN: 0956-5663
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- Citations: 47
Trouillon R, Kang D-K, Chang S-I, et al., 2011, Angiogenin induces nitric oxide release independently from its RNase activity, CHEMICAL COMMUNICATIONS, Vol: 47, Pages: 3421-3423, ISSN: 1359-7345
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- Citations: 13
Trouillon R, O'Hare D, Einaga Y, 2011, Effect of the doping level on the biological stability of hydrogenated boron doped diamond electrodes, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 13, Pages: 5422-5429, ISSN: 1463-9076
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- Citations: 33
Bell CG, Anastassiou CA, O'Hare D, et al., 2011, Large-amplitude ac voltammetry: theory for reversible redox reactions in the ``slow scan limit approximation", Electrochimica Acta, Pages: 6131-6141
Bell CG, Anastassiou CA, O'Hare D, et al., 2011, Theory of high frequency, large-amplitude sinusoidal voltammetry for ideal surface-confined redox systems, Electrochimica Acta
Bell CG, Anastassiou CA, O'Hare D, et al., 2011, Theory of large-amplitude sinusoidal voltammetry for reversible redox reactions, Electrochimica Acta
Kim J-Y, deMello AJ, Chang S-I, et al., 2011, Thermoset polyester droplet-based microfluidic devices for high frequency generation, LAB ON A CHIP, Vol: 11, Pages: 4108-4112, ISSN: 1473-0197
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- Citations: 17
Trouillon R, O'Hare D, 2010, Comparison of glassy carbon and boron doped diamond electrodes: Resistance to biofouling, ELECTROCHIMICA ACTA, Vol: 55, Pages: 6586-6595, ISSN: 0013-4686
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- Citations: 87
Trouillon R, Cheung C, Patel BA, et al., 2010, Electrochemical study of the intracellular transduction of vascular endothelial growth factor induced nitric oxide synthase activity using a multi-channel biocompatible microelectrode array, BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS, Vol: 1800, Pages: 929-936, ISSN: 0304-4165
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- Citations: 17
Trouillon R, Kang D-K, Park H, et al., 2010, Angiogenin Induces Nitric Oxide Synthesis in Endothelial Cells through PI-3 and Akt Kinases, BIOCHEMISTRY, Vol: 49, Pages: 3282-3288, ISSN: 0006-2960
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- Citations: 40
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