Publications
199 results found
Sharma S, Huang Z, Rogers M, et al., 2016, Evaluation of a minimally invasive glucose biosensor for continuous tissue monitoring, Analytical and Bioanalytical Chemistry, Vol: 408, Pages: 8427-8435, ISSN: 1618-2650
We describe here a minimally invasive glucose biosensor based on a microneedle array electrode fabricated from an epoxy-based negative photoresist (SU8 50) and designed for continuous measurement in the dermal compartment with minimal pain. These minimally invasive, continuous monitoring sensor devices (MICoMS) were produced by casting the structures in SU8 50, crosslinking and then metallising them with platinum or silver to obtain the working and reference electrodes, respectively. The metallised microneedle array electrodes were subsequently functionalised by entrapping glucose oxidase in electropolymerised polyphenol (PP) film. Sensor performance in vitro showed that glucose concentrations down to 0.5 mM could be measured with a response times (T90) of 15 s. The effect of sterilisation by Co60 irradiation was evaluated. In preparation for further clinical studies, these sensors were tested in vivo in a healthy volunteer for a period of 3–6 h. The sensor currents were compared against point measurements obtained with a commercial capillary blood glucometer. The epoxy MICoMS devices showed currents values that could be correlated with these.
Hamaoui K, Aftab A, Gowers S, et al., 2016, An ex vivo comparison of adenosine and lidocaine solution and University of Wisconsin solution for hypothermic machine perfusion of porcine kidneys: potential for development, JOURNAL OF SURGICAL RESEARCH, Vol: 208, Pages: 219-229, ISSN: 0022-4804
Hartings JA, Shuttleworth CW, Kirov SA, et al., 2016, The continuum of spreading depolarizations in acute cortical lesion development: Examining Leão's legacy., Journal of Cerebral Blood Flow & Metabolism, Vol: 37, Pages: 1571-1594, ISSN: 0271-678X
A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed as diffusion restriction in magnetic resonance imaging and define the ischemic core. In delayed lesion growth, transient spreading depolarizations arise spontaneously in the ischemic penumbra and induce further persistent depolarization and excitotoxic damage, progressively expanding the ischemic core. The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion development. These pathophysiologic concepts establish a working hypothesis for translation to human disease, where complex patterns of depolarizations are observed in acute brain injury and appear to mediate and signal ongoing secondary damage.
Dreier JP, Fabricius M, Ayata C, et al., 2016, Recording, analysis, and interpretation of spreading depolarizations in neurointensive care: Review and recommendations of the COSBID research group., Journal of Cerebral Blood Flow & Metabolism, ISSN: 0271-678X
Spreading depolarizations (SD) are waves of abrupt, near-complete breakdown of neuronal transmembrane ion gradients, are the largest possible pathophysiologic disruption of viable cerebral gray matter, and are a crucial mechanism of lesion development. Spreading depolarizations are increasingly recorded during multimodal neuromonitoring in neurocritical care as a causal biomarker providing a diagnostic summary measure of metabolic failure and excitotoxic injury. Focal ischemia causes spreading depolarization within minutes. Further spreading depolarizations arise for hours to days due to energy supply-demand mismatch in viable tissue. Spreading depolarizations exacerbate neuronal injury through prolonged ionic breakdown and spreading depolarization-related hypoperfusion (spreading ischemia). Local duration of the depolarization indicates local tissue energy status and risk of injury. Regional electrocorticographic monitoring affords even remote detection of injury because spreading depolarizations propagate widely from ischemic or metabolically stressed zones; characteristic patterns, including temporal clusters of spreading depolarizations and persistent depression of spontaneous cortical activity, can be recognized and quantified. Here, we describe the experimental basis for interpreting these patterns and illustrate their translation to human disease. We further provide consensus recommendations for electrocorticographic methods to record, classify, and score spreading depolarizations and associated spreading depressions. These methods offer distinct advantages over other neuromonitoring modalities and allow for future refinement through less invasive and more automated approaches.
Papadimitriou K, Wang C, Rogers M, et al., 2016, High-Performance Bioinstrumentation for Real-Time Neuroelectrochemical Traumatic Brain Injury Monitoring, Frontiers in Human Neuroscience, Vol: 10, ISSN: 1662-5161
Traumatic brain injury (TBI) has been identified as an important cause of death and severe disability in all age groups and particularly in children and young adults. Central to TBI’s devastation is a delayed secondary injury that occurs in 30-40% of TBI patients each year, while they are in the hospital Intensive Care Unit (ICU). Secondary injuries reduce survival rate after TBI and usually occur within 7 days post-injury. State-of-art monitoring of secondary brain injuries benefits from the acquisition of high-quality and time-aligned electrical data i.e. ElectroCorticoGraphy (ECoG) recorded by means of strip electrodes placed on the brain’s surface, and neurochemical data obtained via rapid sampling microdialysis and microfluidics-based biosensors measuring brain tissue levels of glucose, lactate and potassium. This article progresses the field of multi-modal monitoring of the injured human brain by presenting the design and realisation of a new, compact, medical-grade amperometry, potentiometry and ECoG recording bioinstrumentation. Our combined TBI instrument enables the high-precision, real-time neuroelectrochemical monitoring of TBI patients, who have undergone craniotomy neurosurgery and are treated sedated in the ICU. Electrical and neurochemical test measurements are presented, confirming the high-performance of the reported TBI bioinstrumentation.
Hassan S, Nightingale AM, Leong CL, et al., 2016, Wearable droplet-based microfluidic sensor device for continuous sampling and real-time analysis, Pages: 43-44
This paper reports a wearable droplet-microfluidic based continuous chemical sensing device. The device combines microdialysis and droplet microfluidic techniques, can continuously sample from interstitial or other body fluids into nanolitre droplets and perform biochemical assays and measurements in situ and in real-time.
Hamaoui K, Gowers S, Damji S, et al., 2016, Rapid sampling microdialysis as a novel tool for parenchyma assessment during static cold storage and hypothermic machine perfusion in a translational ex vivo porcine kidney model, Journal of Surgical Research, Vol: 200, Pages: 332-345, ISSN: 1095-8673
BackgroundViability assessment during preservation is imperative to avoid unnecessary discard of marginal organs maximizing graft outcomes in kidney transplantation. To address this need, we have developed a novel system based on a rapid sampling microdialysis (rsMD) analyzer allowing continuous tissue monitoring and measurement of metabolic markers of cell damage. Our aim was to develop a tool that allows for accurate assessment of tissue metabolism and organ viability in the preservation period.MethodsTwenty-two porcine kidneys subjected to 15 min of warm ischemia underwent either 24 h of static cold storage (SCS) or 10 h of hypothermic machine perfusion (HMP). After preservation, tissue temperature was allowed to passively increase to ambient temperature as an ischemic challenge. Cortical and medullary metabolism was monitored throughout with online measurements of lactate concentrations made every 60 s.ResultsOn commencement of monitoring, lactate concentrations were successfully detected within 15 mins. During the initial 1.5 h, lactate concentrations were similar during SCS (65 μM) and HMP (124 μM, P > 0.05) but lower after 10 h of SCS (SCS: 68 μM versus HMP: 230 μM, P < 0.001). Warming data suggest a resilience of HMP kidneys to subsequent temperature induced ischemia compared to SCS kidneys.ConclusionsThis preliminary study provides the baseline ischemic profile for porcine kidneys while validating the technique of rsMD as a tool for organ viability assessment during preservation. The data characterize metabolic differences between SCS and HMP preserved allografts and can help elucidate why HMP is clinically superior to SCS allowing development of interventions to augment these benefits.
Moser N, Leong CL, Hu Y, et al., 2016, An Ion Imaging ISFET Array for Potassium and Sodium Detection, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2847-2850, ISSN: 0271-4302
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- Citations: 17
Gowers SAN, Curto VF, Seneci CA, et al., 2015, A 3D printed microfluidic device with integrated biosensors for online analysis of subcutaneous human microdialysate, Analytical Chemistry, Vol: 87, Pages: 7763-7770, ISSN: 0003-2700
This work presents the design, fabrication, and characterization of a robust 3D printed microfluidic analysis system that integrates with FDA-approved clinical microdialysis probes for continuous monitoring of human tissue metabolite levels. The microfluidic device incorporates removable needle type integrated biosensors for glucose and lactate, which are optimized for high tissue concentrations, housed in novel 3D printed electrode holders. A soft compressible 3D printed elastomer at the base of the holder ensures a good seal with the microfluidic chip. Optimization of the channel size significantly improves the response time of the sensor. As a proof-of-concept study, our microfluidic device was coupled to lab-built wireless potentiostats and used to monitor real-time subcutaneous glucose and lactate levels in cyclists undergoing a training regime.
Hutchinson PJ, Jalloh I, Helmy A, et al., 2015, Consensus statement from the 2014 International Microdialysis Forum., Intensive Care Medicine, Vol: 41, Pages: 1517-1528, ISSN: 1432-1238
Microdialysis enables the chemistry of the extracellular interstitial space to be monitored. Use of this technique in patients with acute brain injury has increased our understanding of the pathophysiology of several acute neurological disorders. In 2004, a consensus document on the clinical application of cerebral microdialysis was published. Since then, there have been significant advances in the clinical use of microdialysis in neurocritical care. The objective of this review is to report on the International Microdialysis Forum held in Cambridge, UK, in April 2014 and to produce a revised and updated consensus statement about its clinical use including technique, data interpretation, relationship with outcome, role in guiding therapy in neurocritical care and research applications.
Wu W, Vitharana K, Gorgy T, et al., 2015, A Method for Voltage Measurements of Cancerous vs Non-cancerous Omentum, 37th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC), Publisher: IEEE, Pages: 7514-7517, ISSN: 1557-170X
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- Citations: 2
Lawrance D, Williamson C, Boutelle MG, et al., 2015, Development of a disposable bile acid biosensor for use in the management of cholestasis, ANALYTICAL METHODS, Vol: 7, Pages: 3714-3719, ISSN: 1759-9660
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- Citations: 6
Gorgy T, Paterson A, Vitharana K, et al., 2014, MOLECULAR PHYSIOLOGY MONITORING OF OVARIAN CANCER EX VIVO, INTERNATIONAL JOURNAL OF GYNECOLOGICAL CANCER, Vol: 24, Pages: 402-402, ISSN: 1048-891X
Fotopoulou C, Gorgy T, Paterson A, et al., 2014, Molecular physiology monitoring of ovarian cancer ex vivo., Annual Meeting of the American-Society-of-Clinical-Oncology (ASCO) / Clinical Science Symposium on Predicting and Improving Adverse Outcomes in Older Adults with Cancer, Publisher: LIPPINCOTT WILLIAMS & WILKINS, 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA, ISSN: 1048-891X
Jeffcote T, Jewell S, Pahl C, et al., 2014, INTRAPARENCHYMAL ELECTRODE RECORDINGS OF CORTICAL SPREADING DEPOLARISATION AND CONTINUOUS SEIZURE ACTIVITY - NEUROVASCULAR DISRUPTION AND SEIZURE OXYGEN THRESHOLDS, 11th Symposium of the International-Neurotrauma-Society, Publisher: MARY ANN LIEBERT, INC, Pages: A51-A51, ISSN: 0897-7151
Jeffcote T, Hinzman JM, Jewell SL, et al., 2014, Detection of spreading depolarization with intraparenchymal electrodes in the injured human brain, Neurocritical Care, Vol: 20, Pages: 21-31, ISSN: 1541-6933
BackgroundSpreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can be detected using intra-cortical electrodes, opening the way for electrode insertion via burr hole.MethodsAnimal work was carried out on adult Sprague–Dawley rats in a laboratory setting to investigate the feasibility of recording depolarization events. Subsequently, 8 human patients requiring craniotomy for traumatic brain injury or aneurysmal subarachnoid hemorrhage were monitored for depolarization events in an intensive care setting with concurrent strip (subdural) and depth (intra-parenchymal) electrode recordings.Results(1) Depolarization events can be reliably detected from intra-cortically placed electrodes. (2) A reproducible slow potential change (SPC) waveform morphology was identified from intra-cortical electrodes on the depth array. (3) The depression of cortical activity known to follow depolarization events was identified consistently from both intra-cortical and sub-cortical electrodes on the depth array.ConclusionsIntra-parenchymally sited electrodes can be used to consistently identify depolarization events in humans. This technique greatly extends the capability of monitoring for spreading depolarization events in injured patients, as electrodes can be sited without the need for craniotomy. The method provides a new investigative tool for the evaluation of the contribution of these events to secondary brain injury in human patients.
Kothur RR, Hall J, Patel BA, et al., 2014, A low pH sensor from an esterified pillar[5]arene, CHEMICAL COMMUNICATIONS, Vol: 50, Pages: 852-854, ISSN: 1359-7345
Hamaoui K, Smith R, Gowers S, et al., 2013, GRAFT PRECONDITIONING USING LOCALISING ANTICOAGULANT FUSION PROTEINS IN KIDNEY TRANSPLANTATION, TRANSPLANT INTERNATIONAL, Vol: 26, Pages: 67-67, ISSN: 0934-0874
Hamaoui K, Gowers S, Mastoridis S, et al., 2013, NOVEL REAL-TIME MICRODIALYSIS MONITORING OF TISSUE VIABILITY - A PROMISING NEW TOOL IN MARGINAL KIDNEY TRANSPLANTATION?, TRANSPLANT INTERNATIONAL, Vol: 26, Pages: 336-336, ISSN: 0934-0874
Hamaoui K, Aftab A, Gowers S, et al., 2013, A NOVEL ADENOSINE/LIDOCAINE PRESERVATION SOLUTION FOR RENAL MACHINE PERFUSION - A POTENTIAL ALTERNATIVE TO UNIVERSITY OF WISCONSIN SOLUTION?, TRANSPLANT INTERNATIONAL, Vol: 26, Pages: 336-336, ISSN: 0934-0874
Boutelle MG, Rogers ML, Leong CL, et al., 2013, The dynamics of glucose and lactate metabolism in the injured brain during spreading depolarisation, 24th Biennial Meeting of the International-Society-for-Neurochemistry and the American-Society-for-Neurochemistry, Publisher: WILEY-BLACKWELL, Pages: 48-48, ISSN: 0022-3042
Rogers ML, Feuerstein D, Leong CL, et al., 2013, Continuous Online Microdialysis Using Microfluidic Sensors: Dynamic Neurometabolic Changes during Spreading Depolarization, ACS CHEMICAL NEUROSCIENCE, Vol: 4, Pages: 799-807, ISSN: 1948-7193
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- Citations: 60
Rogers ML, Brennan PA, Leong CL, et al., 2013, Online rapid sampling microdialysis (rsMD) using enzyme-based electroanalysis for dynamic detection of ischaemia during free flap reconstructive surgery, ANALYTICAL AND BIOANALYTICAL CHEMISTRY, Vol: 405, Pages: 3881-3888, ISSN: 1618-2642
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- Citations: 27
Córcoles EP, Boutelle MG, 2013, The need for invasive sensing, SpringerBriefs in Applied Sciences and Technology, Pages: 3-4
The fast progress in medicinal therapies, clinical instrumentation and drugs development have contributed paradoxically to higher demand for patient monitoring in healthcare systems. The higher increase in chronic patients and an aging population has led to the use of intensive and invasive methods in general wards areas, which otherwise were reserved for patients in high level of care environments, such as intensive care units.
Sansuk S, Bitziou E, Joseph MB, et al., 2013, Ultrasensitive Detection of Dopamine Using a Carbon Nanotube Network Microfluidic Flow Electrode, ANALYTICAL CHEMISTRY, Vol: 85, Pages: 163-169, ISSN: 0003-2700
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- Citations: 96
Córcoles EP, Boutelle MG, 2013, Implantable biosensors, SpringerBriefs in Applied Sciences and Technology, Pages: 21-41
Implantable biosensors have been recognised for their ability to continuously monitor with minimal patient intervention compared with common procedure in clinical environments, such as introduction of catheters and surgical drains.
Córcoles EP, Boutelle MG, 2013, Microdialysis, SpringerBriefs in Applied Sciences and Technology, Pages: 45-47
Microdialysis (MD) is a well-established extracting technique. Its beginnings go back to 1966 when Bito et al. inserted a sterile dialysis sac into a dog’s cortex.
Córcoles EP, Boutelle MG, 2013, Progress in sensor biocompatibility, SpringerBriefs in Applied Sciences and Technology, Pages: 15-20
Two main approaches have been followed to improve sensors biocompatibility: elimination of biological responses by means of coatings and surface modifications, and substance releasing sensors that increase this biological response further.
Córcoles EP, Boutelle MG, 2013, Microdialysis probe requirements, SpringerBriefs in Applied Sciences and Technology, Pages: 49-58
Materials such as cellulose, cuprophane and hospal were extensively used to fabricate MD membranes, since chemical composition was considered to play an important role in the in vitro recovery. Commercially available clinical probes are now being fabricated with supported polycrystalline, polyethylene terephthalate (PET) membranes with specific weight cut-off, typically of 20 kDa and 1 MDa in case of macromolecules studies.
Córcoles EP, Boutelle MG, 2013, Microdialysis coupled with biosensors, SpringerBriefs in Applied Sciences and Technology, Pages: 59-61
During conventional microdialysis, dialysate samples are periodically analysed offline by lab bench instruments. This approach is inadequate for some applications, especially those that require high temporal resolution and rapid data collection.
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