A5050064950- Analytical Chemistry and Sensors
- Electrochemical Analysis and Applications
- Electrochemical sensors and biosensors
- Neuroscience and Neuropharmacology Research
- Microfluidic and Capillary Electrophoresis Applications
- Traumatic Brain Injury and Neurovascular Disturbances
- Neuroscience and Neural Engineering
- Ion channel regulation and function
- Amyotrophic Lateral Sclerosis Research
- Neurogenetic and Muscular Disorders Research
- Innovative Microfluidic and Catalytic Techniques Innovation
- Epilepsy research and treatment
- 3D Printing in Biomedical Research
- Conducting polymers and applications
- EEG and Brain-Computer Interfaces
- Renal Transplantation Outcomes and Treatments
- Cardiac Arrest and Resuscitation
- Organ Transplantation Techniques and Outcomes
- Cardiac electrophysiology and arrhythmias
- Optical Imaging and Spectroscopy Techniques
- Antibiotics Pharmacokinetics and Efficacy
- Functional Brain Connectivity Studies
- X-ray Diffraction in Crystallography
- Muscle activation and electromyography studies
- Crystallization and Solubility Studies
Imperial College London
2016-2025
Johannes Kepler University of Linz
2025
Imperial Valley College
2013-2019
Transnational Press London
2016-2019
King's College London
1997-2016
Faculty (United Kingdom)
2016
Engineering (Italy)
2016
Imperial College Healthcare Charity
2016
Imperial College Healthcare NHS Trust
2016
Hammersmith Hospital
2016
Background and Purpose— Cortical spreading depression (CSD) has been much studied experimentally but never demonstrated unequivocally in human neocortex by direct electrophysiological recording. A similar phenomenon, peri-infarct depolarization, occurs experimental models of stroke causes the infarct to enlarge. Our current understanding mechanisms deterioration days after major traumatic or ischemic brain injury humans not yielded any effective, novel drug treatment. This study sought clear...
Electrocorticographic (ECoG) activity was recorded for up to 129 h from 12 acutely brain-injured human patients using six platinum electrodes placed near foci of damaged cortical tissue. The method probes ECoG in the immediate vicinity injured cortex and adjacent supposedly healthy Six out twelve displayed a total 73 spontaneous episodes spreading depression ECoG. Of remaining 6 1 an episode synchronous during surgery. Using same we also measured slow potential changes (SPC) (0.005-0.05 Hz)...
Microdialysis enables the chemistry of extracellular interstitial space to be monitored. Use this technique in patients with acute brain injury has increased our understanding pathophysiology several neurological disorders. In 2004, a consensus document on clinical application cerebral microdialysis was published. Since then, there have been significant advances use neurocritical care. The objective review is report International Forum held Cambridge, UK, April 2014 and produce revised...
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 human tissue metabolite levels. The device incorporates removable needle type integrated biosensors glucose lactate, which are optimized high concentrations, housed in novel electrode holders. A soft compressible elastomer at base holder ensures good seal chip. Optimization channel size...
Abstract: The effects of mild stress on nonoxidative glucose metabolism were studied in the brain freely moving rat. Extracellular lactate levels hippocampus and striatum monitored at 2.5‐min intervals with microdialysis coupled an enzyme‐based flow injection analysis system. Ten minutes restraint led to a 235% increase extracellular striatum. A 5‐min tail pinch caused 193% 170% hippocampus. Local application tetrodotoxin blocked rise following inhibited subsequent clearance from fluid....
Knowing how biomarker levels vary within biological fluids over time can produce valuable insight into tissue physiology and pathology, could inform personalised clinical treatment. We describe here a wearable sensor for monitoring biomolecule that combines continuous fluid sampling with in situ analysis using wet-chemical assays (with the specific assay interchangeable depending on target biomolecule). The microfluidic device employs droplet flow regime to maximise temporal response of...
Spreading depolarizations (SDs) occur spontaneously with high incidence in patients acute brain injury. They can be detected by subdural electrocorticographic recordings. We here characterize the dynamic metabolic response to these events. A microdialysis catheter was inserted into perilesional cortical tissue adjacent a strip for electrocorticography following craniotomy 10 patients. The connected an online assay measuring glucose and lactate concentrations every 30 60 secs. Spontaneously...
We describe here a minimally invasive glucose biosensor based on 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 invasive, monitoring sensor devices (MICoMS) were produced by casting structures SU8 50, crosslinking then metallising them platinum or silver to obtain working reference electrodes, respectively. The metallised electrodes subsequently functionalised...
The electrochemical measurement of dopamine (DA), in phosphate buffer solution (pH 7.4), with a limit detection (LOD) ∼5 pM 50 μL (∼ 250 attomol) is achieved using band electrode comprised sparse network pristine single-walled carbon nanotubes (SWNTs), which covers <1% the insulating substrate. SWNT electrodes are deployed as amperometric (anodic) detectors microfluidic cells, produced by microstereolithography, designed specifically for flow injection analysis (FIA). have channel (duct)...
Abstract: The relationship between brain extracellular glucose levels and neuronal activity was evaluated using microdialysis in awake, freely moving rats. sodium channel blocker tetrodotoxin the depolarizing agent veratridine were administered through dialysis probe to provoke local changes activity. content significantly increased presence of decreased sharply following application. systemic injection a general anaesthetic, chloral hydrate, led large prolonged increase levels....
The pathophysiology of peri-lesion boundary zones in acute brain injury is highly dynamic, and it now clear that spreading-depression-like events occur frequently areas cerebral cortex adjacent to contusions the injured human brain. An automated method assay microdialysate from 11 patients with intracranial haematomas requiring surgery was used. Perfusate (2 μL/min) flowed directly into a flow-injection system for glucose lactate at intervals typically 30 secs each. Four channels...
Neuronal activity is tightly coupled with brain energy metabolism. Numerous studies have suggested that lactate equally important as an substrate for neurons glucose. Lactate production reportedly triggered by glutamate uptake, and independent of receptor activation. Here we show climbing fibre stimulation cerebellar Purkinje cells increased extracellular 30% within 30 s stimulation, but not briefer periods. To explore whether was controlled pre‐ or postsynaptic events silenced AMPA...
Rapid sampling microdialysis (rsMD) directed towards the cerebral cortex has allowed identification of a combined time-series signature for glucose and lactate that characterizes peri-infarct depolarization in experimental focal ischaemia, but no comparable data exist ‘classical’ cortical spreading depression (CSD) associated with hyperaemia normally perfused brain. Here, we examined rsMD responses dialysate to five hyperaemic depressions induced intracortical microinjections, typically 1...
Spreading depolarizations occur spontaneously and frequently in injured human brain. They propagate slowly through tissue often cycling around a local area of damage. Tissue recovery after an spreading depolarization requires greatly augmented energy utilisation to normalise ionic gradients from virtually complete loss membrane potential. In the brain, this is difficult because blood flow low unreactive. study, we use new variant microdialysis, continuous on-line observe effects on brain...
Developing tools that are able to monitor transient neurochemical dynamics is important decipher brain chemistry and function. Multifunctional polymer-based fibers have been recently applied modulate neural activity. Here, we explore the potential of polymer comprising six graphite-doped electrodes two microfluidic channels within a flexible polycarbonate body as platform for sensing pH neurometabolic lactate. Electrodes were made into potentiometric sensors (responsive pH) or amperometric...
1. This study is concerned with the supply of metabolic substrates for neuronal metabolism. Experiments were carried out to investigate whether mechanisms demonstrated in cultured astrocytes also occurred vivo; these cAMP‐mediated breakdown glycogen and glutamate uptake‐stimulated release lactate. 2. In vivo microdialysis was used freely moving rats. Lactate glucose dialysate assayed using enzyme‐based on‐line assays. Drugs given locally through dialysis probe. Regional cerebral blood flow...
Abstract: We have used a glucose oxidase‐based sensor implanted in the striatum of freely moving rats to determine concentration extracellular two distinct ways. With modification zero net flux method, which different concentrations are infused through dialysis probe glued biosensor, we calculated at there was no change current by regression analysis; this gave 0.351 ± 0.016 m M . Calculating from basal and vitro calibration biosensor not significantly this. The determined either method...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnzyme packed bed system for the on-line measurement of glucose, glutamate, and lactate in brain microdialyzateMartyn G. Boutelle, Lesley K. Fellows, Colin. CookCite this: Anal. Chem. 1992, 64, 17, 1790–1794Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September 1992https://pubs.acs.org/doi/10.1021/ac00041a010https://doi.org/10.1021/ac00041a010research-articleACS PublicationsRequest...
A new approach to signal processing of analytical time-domain data is presented. It consists in identifying the types noise, characterizing them, and subsequently subtracting them from otherwise unprocessed set. The algorithms have been successfully applied three classes noise commonly found signals: spikes, ripples, baseline drift. Traditional filters used as an intermediary step detect remove spikes with 96.8% success. Adaptive ensemble average subtraction has developed nonstationary...