scholarly journals Fabrication of Patterned Integrated Electrochemical Sensors

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Muhammad Mujeeb-U-Rahman ◽  
Dvin Adalian ◽  
Axel Scherer
Keyword(s):  
Electrochemical Sensors ◽  
Measurement Techniques ◽  
Glucose Sensing ◽  
Small Surface ◽  
Fully Integrated ◽  
Nanoscale Patterning ◽  
Sensing Applications ◽  
Sensing Platforms ◽  
Integrated Microsystems ◽  
Electronic Measurement

Fabrication of integrated electrochemical sensors is an important step towards realizing fully integrated and truly wireless platforms for many local, real-time sensing applications. Micro/nanoscale patterning of small area electrochemical sensor surfaces enhances the sensor performance to overcome the limitations resulting from their small surface area and thus is the key to the successful miniaturization of integrated platforms. We have demonstrated the microfabrication of electrochemical sensors utilizing top-down lithography and etching techniques on silicon and CMOS substrates. This choice of fabrication avoids the need of bottom-up techniques that are not compatible with established methods for fabricating electronics (e.g., CMOS) which form the industrial basis of most integrated microsystems. We present the results of applying microfabricated sensors to various measurement problems, with special attention to their use for continuous DNA and glucose sensing. Our results demonstrate the advantages of using micro- and nanofabrication techniques for the miniaturization and optimization of modern sensing platforms that employ well-established electronic measurement techniques.

Improved micro-impedance spectroscopy to determine cell barrier properties

2020 ◽  
Vol 4 (3) ◽  
pp. 150-155 ◽  
Author(s):  
Md. Mehadi Hasan Sohag ◽  
Olivier Nicoud ◽  
Racha Amine ◽  
Abir Khalil-Mgharbel ◽  
Jean-Pierre Alcaraz ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Epithelial Cells ◽  
Lipid Bilayers ◽  
Cultured Cells ◽  
Cell Model ◽  
Measurement Techniques ◽  
Cell Monolayer ◽  
Microfluidic Channel ◽  
Small Surface ◽  
Resistance Pathway

AbstractThe goal of this study was to determine whether the Tethapod system, which was designed to determine the impedance properties of lipid bilayers, could be used for cell culture in order to utilise micro-impedance spectroscopy to examine further biological applications. To that purpose we have used normal epithelial cells from kidney (RPTEC) and a kidney cancer cell model (786-O). We demonstrate that the Tethapod system is compatible with the culture of 10,000 cells seeded to grow on a small area gold measurement electrode for several days without affecting the cell viability. Furthermore, the range of frequencies for EIS measurements were tuned to examine easily the characteristics of the cell monolayer. We demonstrate significant differences in the paracellular resistance pathway between normal and cancer kidney epithelial cells. Thus, we conclude that this device has advantages for the study of cultured cells that include (i) the configuration of measurement and reference electrodes across a microfluidic channel, and (ii) the small surface area of 6 parallel measurement electrodes (2.1 mm2) integrated in a microfluidic system. These characteristics might improve micro-impedance spectroscopy measurement techniques to provide a simple tool for further studies in the field of the patho-physiology of biological barriers.

scholarly journals On the use of plume models to estimate the flux in volcanic gas plumes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julia Woitischek ◽  
Nicola Mingotti ◽  
Marie Edmonds ◽  
Andrew W. Woods
Keyword(s):  
Electrochemical Sensors ◽  
Measurement Techniques ◽  
Flux Measurement ◽  
Hydrothermal Systems ◽  
Mount Etna ◽  
Volcanic Gas ◽  
Gas Flux ◽  
Convective Structures ◽  
Video Images ◽  
Villarrica Volcano

AbstractMany of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux.

scholarly journals Utilising Commercially Fabricated Printed Circuit Boards as an Electrochemical Biosensing Platform

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 793
Author(s):  
Uroš Zupančič ◽  
Joshua Rainbow ◽  
Pedro Estrela ◽  
Despina Moschou
Keyword(s):  
Printed Circuit Boards ◽  
Electrochemical Sensors ◽  
Cost Effective ◽  
Electrochemical Sensing ◽  
Label Free ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Sensing Applications ◽  
Electrochemical Biosensing ◽  
Pre Treatment

Printed circuit boards (PCBs) offer a promising platform for the development of electronics-assisted biomedical diagnostic sensors and microsystems. The long-standing industrial basis offers distinctive advantages for cost-effective, reproducible, and easily integrated sample-in-answer-out diagnostic microsystems. Nonetheless, the commercial techniques used in the fabrication of PCBs produce various contaminants potentially degrading severely their stability and repeatability in electrochemical sensing applications. Herein, we analyse for the first time such critical technological considerations, allowing the exploitation of commercial PCB platforms as reliable electrochemical sensing platforms. The presented electrochemical and physical characterisation data reveal clear evidence of both organic and inorganic sensing electrode surface contaminants, which can be removed using various pre-cleaning techniques. We demonstrate that, following such pre-treatment rules, PCB-based electrodes can be reliably fabricated for sensitive electrochemical biosensors. Herein, we demonstrate the applicability of the methodology both for labelled protein (procalcitonin) and label-free nucleic acid (E. coli-specific DNA) biomarker quantification, with observed limits of detection (LoD) of 2 pM and 110 pM, respectively. The proposed optimisation of surface pre-treatment is critical in the development of robust and sensitive PCB-based electrochemical sensors for both clinical and environmental diagnostics and monitoring applications.

scholarly journals Recent developments in carbon-based two-dimensional materials: synthesis and modification aspects for electrochemical sensors

2020 ◽  
Vol 187 (8) ◽  
Author(s):  
Eva-Maria Kirchner ◽  
Thomas Hirsch
Keyword(s):  
Carbon Materials ◽  
Electrochemical Sensors ◽  
Field Effect Transistors ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Wide Field ◽  
Two Dimensional ◽  
Sensing Applications ◽  
The Impact ◽  
Carbon Based

Abstract This review (162 references) focuses on two-dimensional carbon materials, which include graphene as well as its allotropes varying in size, number of layers, and defects, for their application in electrochemical sensors. Many preparation methods are known to yield two-dimensional carbon materials which are often simply addressed as graphene, but which show huge variations in their physical and chemical properties and therefore on their sensing performance. The first section briefly reviews the most promising as well as the latest achievements in graphene synthesis based on growth and delamination techniques, such as chemical vapor deposition, liquid phase exfoliation via sonication or mechanical forces, as well as oxidative procedures ranging from chemical to electrochemical exfoliation. Two-dimensional carbon materials are highly attractive to be integrated in a wide field of sensing applications. Here, graphene is examined as recognition layer in electrochemical sensors like field-effect transistors, chemiresistors, impedance-based devices as well as voltammetric and amperometric sensors. The sensor performance is evaluated from the material’s perspective of view and revealed the impact of structure and defects of the 2D carbon materials in different transducing technologies. It is concluded that the performance of 2D carbon-based sensors is strongly related to the preparation method in combination with the electrical transduction technique. Future perspectives address challenges to transfer 2D carbon-based sensors from the lab to the market.

scholarly journals Electrochemical Detection of Neurotransmitters

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 101 ◽  
Author(s):  
Saikat Banerjee ◽  
Stephanie McCracken ◽  
Md Faruk Hossain ◽  
Gymama Slaughter
Keyword(s):  
Nervous System ◽  
Measurement Techniques ◽  
Electrochemical Measurement ◽  
High Temporal Resolution ◽  
Sensing Platforms ◽  
Target Analytes ◽  
Assessment Techniques ◽  
The Brain ◽  
Significant Attention ◽  
Chemical Messengers

Neurotransmitters are important chemical messengers in the nervous system that play a crucial role in physiological and physical health. Abnormal levels of neurotransmitters have been correlated with physical, psychotic, and neurodegenerative diseases such as Alzheimer’s, Parkinson’s, dementia, addiction, depression, and schizophrenia. Although multiple neurotechnological approaches have been reported in the literature, the detection and monitoring of neurotransmitters in the brain remains a challenge and continues to garner significant attention. Neurotechnology that provides high-throughput, as well as fast and specific quantification of target analytes in the brain, without negatively impacting the implanted region is highly desired for the monitoring of the complex intercommunication of neurotransmitters. Therefore, it is crucial to develop clinical assessment techniques that are sensitive and reliable to monitor and modulate these chemical messengers and screen diseases. This review focuses on summarizing the current electrochemical measurement techniques that are capable of sensing neurotransmitters with high temporal resolution in real time. Advanced neurotransmitter sensing platforms that integrate nanomaterials and biorecognition elements are explored.

Assessing the Stability of Inkjet-Printed Carbon Nanotube for Brine Sensing Applications

2020 ◽  
Vol 20 (12) ◽  
pp. 7644-7652
Author(s):  
Khalid Marbou ◽  
Waqas Gil ◽  
Amal Al Ghaferi ◽  
Irfan Saadat ◽  
Khalid Alhammadi ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Electrochemical Sensors ◽  
Sessile Drop ◽  
Synthesis Methods ◽  
Resistance Change ◽  
Sensing Applications ◽  
The Stability ◽  
The Impact ◽  
Oil Gas ◽  
Electrical Resistance Change

In hostile environments, sensing is critical for many industries such as chemical and oil/gas. Within this industry, the deposition of scales or minerals on various infrastructure components (e.g., pipelines) forms a reliability hazard that needs to be monitored. Therefore, the approach adopted in this study to tackle this issue relies on the use of real-time sensing of specific ions in brine, the natural trigger for ions deposition. In order to do so, electrochemical sensors based on carbon nanotubes (CNTs) are developed, taking advantage of their unique properties facilitated by different synthesis and fabrication methods. One of these promising synthesis methods is inkjet printing of CNT films since in general, it has exceptional benefits over other approaches that are used to print CNTs. Furthermore, it does not need the use templates. In addition, it is a very fast technique with consistent printing results for many applications along with very low cost on various shapes/formfactors. As these sensors are exposed to a hostile environment (chemical, temperature, etc.), the stability of the CNT films is of great importance. In this study, a comprehensive investigation of the stability of CNT surfaces upon exposure to elements is presented. Accordingly, the several impacts of this interaction on physical properties of the surfaces as a function of interaction time and brine chemical composition are assessed. Moreover, the approach used for investigating the impact of this exposure involves the following: surface electrical resistance change using four probe measurements; surface roughness/topography using Atomic Force Microscopy (AFM) along Scanning Electron Microscopy (SEM); quality of CNT through Raman spectroscopy and wettability using the sessile drop method. The sensing capabilities of the devices are investigated by looking at the sensing selectivity of target ions, resetting capabilities, and sensing sensitivity manifested in the electrical resistance change. Consequently, our results indicate that while inkjet films are very promising sensor material, the fabrication and long term stability require further optimization of the films along with the process to make them meet reliability and lifetime requirements in the oil/gas hostile operational environments.

Hierarchical ZnO nanorods/Ni(OH)2 nanoflakes for room-temperature, cheap fabrication of non-enzymatic glucose sensors

RSC Advances ◽  
2016 ◽  
Vol 6 (112) ◽  
pp. 111374-111379 ◽  
Author(s):  
V. Strano ◽  
S. Mirabella
Keyword(s):  
Room Temperature ◽  
Zno Nanorods ◽  
Glucose Sensing ◽  
Glucose Sensors ◽  
Hierarchical Nanostructures ◽  
Sensing Applications

Optimization of hierarchical nanostructures composed of Ni(OH)2 nanoflakes on ZnO nanorods (NRs) for inexpensive amperometric glucose sensing applications.

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