Silicon Wafer-Based Platinum Microelectrode Array Biosensor for Near Real-Time Measurement of Glutamate in Vivo

Wassum, Kate M.; Tolosa, Vanessa; Wang, Jianjun; Walker, Edward T.; Monbouquette, Harold G.; Maidment, Nigel T.

doi:10.3390/s8085023

Cited by 124 publications

(150 citation statements)

References 29 publications

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“…One subtype of chemical sensors, enzymatic amperometric sensors, rely on the production and subsequent detection of hydrogen peroxide (H 2 O 2 ) within the sensor. 38 As the footprint of the sensor decreases, the number of H 2 O 2 molecules detected must be maximized to improve sensor performance and one approach to improving this detection is increasing the active surface area of the sensor. To test the sensitivity of the roughened microelectrodes for biosensing applications, Pt microelectrodes were roughened using the procedure outlined above with a range of oxidation pulse amplitudes (1.2-1.4 V).…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

Ivanovskaya

Belle

Yorita

et al. 2018

J. Electrochem. Soc.

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We report a method for electrochemical roughening of thin-film platinum (Pt) electrodes that increases active surface area, decreases electrode impedance, increases charge injection capacity, increases sensitivity of biosensors and improves adhesion of electrochemically deposited films. First, a well-established technique for electrochemical roughening of thick Pt electrodes (wires and foils) by oxidation-reduction pulses was modified for use on thin-film Pt. Optimal roughening of thin-film Pt electrodes with this established protocol in a sulfuric acid solution was found to occur at about four times lower frequency than that typically used for thick Pt. This modification in established procedure created a 21x surface area increase but showed nanoscale cracks from inter-grain Pt dissolution that compromised film integrity. A crack free surface with Pt nanocrystal re-deposition (20-30 nm in size) and higher enhancement in surface area (44x) was obtained when the electrolyte was switched to a non-adsorbing perchloric acid solution. These electrochemically roughened electrodes have charge injection limits comparable to titanium nitride and just below carbon nanotube-based materials. Roughened microelectrodes showed a 2.8x increase in sensitivity to hydrogen peroxide detection, indicative of improved enzymatic biosensor performance. Platinum iridium and iridium oxide coatings on these roughened surfaces showed an improvement in adhesion. Microfabrication techniques have enabled the bulk fabrication of robust, reproducible neural interfaces. 1,2 These neural interfaces typically contain conductive metal electrodes that serve as the 'interface' between the device and the tissue. 3 When microfabricated, these electrodes are typically thin films of metal, a few hundred nanometers thick and recent advances show these interfaces to be constructed on thin flexible substrates, further improving the ability of electrodes to interface with tissue. 4-7 While these thin film electrodes generally act very similar to bulk metal found in non-microfabricated neural interfaces, they can be more delicate than bulk metal, 8 especially when fabricated on a flexible substrate. Both bulk and thin film metal interfaces demand highest performance to ensure that they can properly interface with tissue without causing damage to the tissue. Often, electrode surface modifications are needed to enhance performance.Enhanced electrode performance can be accomplished by 1) roughening the electrode surface to increase the effective surface area; 9-11 or, 2) depositing a thin-film coating of a material with enhanced electrochemical activity. [12][13][14][15] When depositing a different thin film electroactive material over the electrode to improve performance, there is often poor adhesion of the deposited film to the electrode surface. 9,16 Poor film adhesion compromises the mechanical robustness of an implantable device which may result in immediate delamination or decreased lifetime of the electrode upon implantation, ultimately deteriorating sens...

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Section: Resultsmentioning

confidence: 99%

Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

Ivanovskaya

Belle

Yorita

et al. 2018

J. Electrochem. Soc.

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“…Recently, enzyme electrodes have also been integrated on microfabricated probes carrying multiple electrodes [5,6,25,39]. The utilized functionalization methods are similar to previously used single-electrode functionalization methods (drop/dip coating) and are thus limited in upscaling to larger multielectrode ensembles.…”

Section: Introductionmentioning

confidence: 99%

Multisite monitoring of choline using biosensor microprobe arrays in combination with CMOS circuitry

Frey¹,

Rothe²,

Heer³

et al. 2014

Biomedical Engineering / Biomedizinische Technik

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A miniature device enabling parallel in vivo detection of the neurotransmitter choline in multiple brain regions of freely behaving rodents is presented. This is achieved by combining a biosensor microprobe array with a custom-developed CMOS chip. Each silicon microprobe comprises multiple platinum electrodes that are coated with an enzymatic membrane and a permselective layer for selective detection of choline. The biosensors, based on the principle of amperometric detection, exhibit a sensitivity of 157 ± 35 µA mM -1 cm -2 , a limit of detection of below 1 µM, and a response time in the range of 1 s. With on-chip digitalization and multiplexing, parallel recordings can be performed at a high signal-to-noise ratio with minimal space requirements and with substantial reduction of external signal interference. The layout of the integrated circuitry allows for versatile configuration of the current range and can, therefore, also be used for functionalization of the electrodes before use. The result is a compact, highly integrated system, very convenient for on-site measurements.

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“…For example, GLDH-based biocatalytic sensors have utilized pHs ranging from 7.0 to 9.0 during the detection step [12,67,79]. Also, GmOx-based biosensors appear to utilize pHs from 7.0 to 7.4 [40,68]. Of note, the optimal pH of the immobilized enzyme may be slightly different from the free enzyme in buffered aqueous solution.…”

Section: Optimization Of Experimental Conditions and Measurement Platmentioning

confidence: 99%

“…Many glutamate biosensors are based on quantifying the oxidation of hydrogen peroxide (H 2 O 2 ) liberated in a chemical reaction between glutamate oxidase (GmOx, an oxidoreductase enzyme, EC 1.4.3.11) and L-glutamate in the presence of oxygen (O 2 ), water (H 2 O), and a flavin adenine dinucleotide (FAD) cofactor [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. GmOx enzyme catalyzes the oxidative deamination of glutamate resulting in the formation of 2-oxoglutarate (i.e., α-ketoglutarate, α-KG), ammonia (NH 3 ), and H 2 O 2 [46].…”

Section: Glutamate Oxidase-based Biosensorsmentioning

confidence: 99%

Enzyme-Based Electrochemical Glutamate Biosensors

Okon¹,

Ronkainen²

2017

Electrochemical Sensors Technology

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Glutamate, a major excitatory neurotransmitter in the mammalian central nervous system, plays a vital role in many physiological processes and is one of the key neurotransmitters of interest in psychopharmacology. It is involved in many normal and abnormal behaviors related to neurological and psychiatric disorders. The glutamate system has been proposed to play a significant role in various neurological and psychiatric disorders such as Alzheimer's disease, autism, schizophrenia, depression, drug addiction, and more. The design, construction, and optimization of enzyme-based electrochemical biosensors for in vivo and in vitro detection of glutamate are active areas of interdisciplinary research. For example, various glutamate biosensors have been developed for monitoring dynamic levels of extracellular glutamate in the living brain tissue adding to the current medical knowledge of these complex neurotransmitter systems and ultimately impacting treatment plans. In addition to biological sciences and clinical medicine, glutamate biosensors have been used in environmental monitoring, in the fermentation industry, and in the food industry for determination of monosodium glutamate (MSG), a common flavor-enhancing food additive.

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Silicon Wafer-Based Platinum Microelectrode Array Biosensor for Near Real-Time Measurement of Glutamate in Vivo

Cited by 124 publications

References 29 publications

Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

Multisite monitoring of choline using biosensor microprobe arrays in combination with CMOS circuitry

Enzyme-Based Electrochemical Glutamate Biosensors

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