Microelectrode array
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The microelectrode array (MEA) is an electronic device composed of a varying number of microelectrodes used to detect the extracellular field potential generated by excitable tissues. This technology allows for the measurement of electrical activity without damaging the cell membrane during recording. MEA offers a better way of getting long-term recordings and observing different cellular activities than the invasive patch clamp technique. Recent research demonstrates that MEA technology enables scientists to detect both cellular and subcellular events, allowing them to study cellular properties and reactions across different experimental conditions and even to identify distinct ion currents and their impact on cellular electrophysiology. The paper reviews the historical development of MEA technology along with its modern applications for electrophysiological research. The future advancement of MEA technology will improve our knowledge about neuronal and cardiac excitability and expand its use to additional electrically active tissues, advancing research in pharmacology, neuroscience, cardiology, and other fields.
- MeSH
- elektrofyziologické jevy MeSH
- lidé MeSH
- mikroelektrody * MeSH
- preklinické hodnocení léčiv metody přístrojové vybavení MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
We present a custom-made multielectrode array for the recording of evoked potentials during acute experiments in rats, which offers a quick and reliable estimation of the cortical tonotopy. The array consists of electrodes represented by insulated copper wires of 0.09 mm diameter fixed in epoxy resin in a 3 x 5 arrangement, with final impedances of 410-800 kOhm. The array was placed on the brain surface of anesthetized rats approximately at the location of the auditory cortex (AC) and the cortical evoked potentials (middle-latency responses, MLR) were elicited by a series of tone pips of different frequencies at 50 dB of sound pressure level (SPL) intensity. The frequency that evoked the highest MLR amplitude (best frequency, BF) was identified for each electrode. The obtained distribution of the BFs characterized the cortical tonotopy, and it correlated with the frequency selectivity of neurons recorded at the same positions by an extracellular microelectrode. Although the space resolution of the array did not allow for the identification of AC sub regions, the array proved to be a reliable tool for a quick estimation and prediction of areas of interest for the subsequent measurements of neurons by more precise techniques.
- MeSH
- akustická stimulace metody MeSH
- časové faktory MeSH
- implantované elektrody * MeSH
- krysa rodu rattus MeSH
- mapování mozku přístrojové vybavení metody MeSH
- potkani Long-Evans MeSH
- sluchové evokované potenciály fyziologie MeSH
- sluchové korové centrum fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In this work we report on the implementation of methods for data processing signals from microelectrode arrays (MEA) and the application of these methods for signals originated from two types of MEAs to detect putative neurons and sort them into subpopulations. We recorded electrical signals from firing neurons using titanium nitride (TiN) and boron doped diamond (BDD) MEAs. In previous research, we have shown that these methods have the capacity to detect neurons using commercially-available TiN-MEAs. We have managed to cultivate and record hippocampal neurons for the first time using a newly developed custom-made multichannel BDD-MEA with 20 recording sites. We have analysed the signals with the algorithms developed and employed them to inspect firing bursts and enable spike sorting. We did not observe any significant difference between BDD- and TiN-MEAs over the parameters, which estimated spike shape variability per each detected neuron. This result supports the hypothesis that we have detected real neurons, rather than noise, in the BDD-MEA signal. BDD materials with suitable mechanical, electrical and biocompatibility properties have a large potential in novel therapies for treatments of neural pathologies, such as deep brain stimulation in Parkinson's disease.
- MeSH
- akční potenciály MeSH
- algoritmy MeSH
- bor chemie MeSH
- diamant chemie MeSH
- hipokampus fyziologie MeSH
- krysa rodu rattus MeSH
- mikroelektrody MeSH
- neurony fyziologie MeSH
- potkani Wistar MeSH
- titan chemie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The paper describes a novel control strategy for simultaneous manipulation of several microscale particles over a planar microelectrode array using dielectrophoresis. The approach is based on a combination of numerical nonlinear optimization, which gives a systematic computational procedure for finding the voltages applied to the individual electrodes, and exploitation of the intrinsic noise, which compensates for the loss of controllability when two identical particles are exposed to identical forces. Although interesting on its own, the proposed functionality can also be seen as a preliminary achievement in a quest for a technique for separation of two particles. The approach is tested experimentally with polystyrene beads (50 microns in diameter) immersed in deionized water on a flat microelectrode array with parallel electrodes. A digital camera and computer vision algorithm are used to measure the positions. Two distinguishing features of the proposed control strategy are that the range of motion is not limited to interelectrode gaps and that independent manipulation of several particles simultaneously is feasible even on a simple microelectrode array.
- MeSH
- algoritmy MeSH
- design vybavení MeSH
- elektrody MeSH
- elektroforéza metody MeSH
- hluk MeSH
- mikromanipulace přístrojové vybavení metody MeSH
- mikrosféry MeSH
- počítačové zpracování signálu přístrojové vybavení MeSH
- teoretické modely MeSH
- zpětná vazba * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The article deals with selection of a suitable method for an intracranial measurement of physiological parameters of the brain tissue. The goals of a subsequent clinical study will be investigation of the local physiological parameters of the brain tissue (partial pressure of oxygen – PO2, partial pressure of carbon dioxide – PCO2, acidity – pH, electrical activity, etc.) and their relationship with the selected artifi cial lung ventilation parameters. The methods suitable for measuring these physiological parameters include the measuring by metal microelectrodes, microelectrode arrays (MEAs) or optical methods as fi bber-optic sensors and near infrared spectroscopy (NIRS).
- MeSH
- blízká infračervená spektroskopie metody přístrojové vybavení využití MeSH
- experimenty na zvířatech MeSH
- financování organizované MeSH
- mikroelektrody využití MeSH
- monitorování fyziologických funkcí metody přístrojové vybavení využití MeSH
- mozek - chemie fyziologie MeSH
- mozek fyziologie MeSH
- optická vlákna MeSH
- počítačové zpracování signálu přístrojové vybavení MeSH
- potkani Wistar MeSH
- umělé dýchání metody přístrojové vybavení využití MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
Cardiomyocytes (CM) placed on microelectrode array (MEA) were simultaneously probed with cantilever from atomic force microscope (AFM) system. This electric / nanomechanical combination in real time recorded beating force of the CMs cluster and the triggering electric events. Such "organ-on-a-chip" represents a tool for drug development and disease modeling. The human pluripotent stem cells included the WT embryonic line CCTL14 and the induced dystrophin deficient line reprogrammed from fibroblasts of a patient affected by Duchenne Muscular Dystrophy (DMD, complete loss of dystrophin expression). Both were differentiated to CMs and employed with the AFM/MEA platform for diseased CMs' drug response testing and DMD characterization. The dependence of cardiac parameters on extracellular Ca2+ was studied. The differential evaluation explained the observed effects despite variability of biological samples. The β-adrenergic stimulation (isoproterenol) and antagonist trials (verapamil) addressed ionotropic and chronotropic cell line-dependent features. For the first time, a distinctive beating-force relation for DMD CMs was measured on the 3D cardiac in vitro model.
- MeSH
- biosenzitivní techniky * MeSH
- buněčná diferenciace genetika MeSH
- Duchennova muskulární dystrofie patofyziologie MeSH
- dystrofin genetika MeSH
- fibroblasty účinky léků ultrastruktura MeSH
- indukované pluripotentní kmenové buňky metabolismus ultrastruktura MeSH
- isoprenalin farmakologie MeSH
- kardiomyocyty cytologie MeSH
- kontrakce myokardu genetika fyziologie MeSH
- lidé MeSH
- mikroelektrody MeSH
- mikroskopie atomárních sil MeSH
- verapamil farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Objective.Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities.Ex vivo, the retina can be readily investigated using multi electrode arrays (MEAs). However, MEA recording and stimulation from an intact retina (in the eye) has been so far insufficient.Approach.In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20μm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40μm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50μm) PU film. Plasma polymerized 3.4-ethylenedioxythiophene was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both explanted and intact inside an enucleated eye, were used.Main results.A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate.Ex vivoelectrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed.Significance.Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissuein vivo.
- MeSH
- elektrická stimulace metody MeSH
- mikroelektrody MeSH
- retina * fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Používané metody kompenzace ztráty zraku nabízejí jen velmi malý objem přenášené informace. Kožní receptorové pole je informačním kanálem, který je teoreticky schopen přenášet podobně strukturovanou informaci jako sítnice. Snížený objem přenášené informace lze kompenzovat nízkoztrátovou kompresí obrazu pomocí wavelet transformace. Pokrok ve vývoji mikroelektroniky nyní umožňuje vyrobit přenosné zařízení pro kožní reprezentaci vizuálních vjemů s dostatečně dlouhou dobou provozu k rutinnímu využívání pacienty se slepotou či těžkou poruchou zraku. Navržená matice 2400 uhlíkových elektrod napařených na pružnou membránu v provedených experimentech vykazuje dobrou mechanickou odolnost, elektrickou pevnost a dobrou přilnavost ke kůži trupu. Při delším používání se stává problémem pocení se vznikem elektrických můstků mezi elektrodami a dráždění kůže produkty elektrolýzy potu. Přijatelnější alternativou jsou piezoelektrické vibrační stimulátory, které ale nabízejí o něco menší rozlišení stupňů intenzity stimulace. Ve srovnání s experimentálními sítnicovými nebo korovými implantáty nabízí somatosenzorická stimulace řádově vyšší objem přenášené informace.
At present vision prosthesis proposes transmission of only a limited amount of visual information. Cutaneous receptor field may serve as a information channel. It has similar information-processing ability as retina. Lower information capacity of the skin may be compensated by wavelet transform image compression. Advances in microtechnology have facilitated the development of a haptic data visualization system with sufficient life-time for people with visual impairments. Proposed array with 2400 carbon electrodes stewed on elastic membrane in the present experiments demonstrate a good mechanical endurance, electrical stability and adhesivity to the trunk skin. Disadvantageous is short circuits production among near electrodes due to sweating and skin irritation after long term electrical stimulation. Vibrotactile piezo-electric stimulators are safer alternative with lower resolution. Comparing retinal and cortical vision prosthesis offers electrocutaneous communication system comparably higher amount of transmitted information.
