A 16 x 16 CMOS amperometric microelectrode array for simultaneous electrochemical measurements

There is a requirement for an electrochemical sensor technology capable of making multivariate measurements in environmental, healthcare, and manufacturing applications. Here, we present a new device that is highly parallelized with an excellent bandwidth. For the first time, electrochemical cross-talk for a chip-based sensor is defined and characterized. The new CMOS electrochemical sensor chip is capable of simultaneously taking multiple, independent electroanalytical measurements. The chip is structured as an electrochemical cell microarray, comprised of a microelectrode array connected to embedded self-contained potentiostats. Speed and sensitivity are essential in dynamic variable electrochemical systems. Owing to the parallel function of the system, rapid data collection is possible while maintaining an appropriately low-scan rate. By performing multiple, simultaneous cyclic voltammetry scans in each of the electrochemical cells on the chip surface, we are able to show (with a cell-to-cell pitch of 456 μm) that the signal cross-talk is only 12% between nearest neighbors in a ferrocene rich solution. The system opens up the possibility to use multiple independently controlled electrochemical sensors on a single chip for applications in DNA sensing, medical diagnostics, environmental sensing, the food industry, neuronal sensing, and drug discovery

Applications of Graphene Quantum Dots in Biomedical Sensors

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.DFG, 428780268, Biomimetische Rezeptoren auf NanoMIP-Basis zur Virenerkennung und -entfernung mittels integrierter Ansätz

Nanomaterials for Healthcare Biosensing Applications

In recent years, an increasing number of nanomaterials have been explored for their applications in biomedical diagnostics, making their applications in healthcare biosensing a rapidly evolving field. Nanomaterials introduce versatility to the sensing platforms and may even allow mobility between different detection mechanisms. The prospect of a combination of different nanomaterials allows an exploitation of their synergistic additive and novel properties for sensor development. This paper covers more than 290 research works since 2015, elaborating the diverse roles played by various nanomaterials in the biosensing field. Hence, we provide a comprehensive review of the healthcare sensing applications of nanomaterials, covering carbon allotrope-based, inorganic, and organic nanomaterials. These sensing systems are able to detect a wide variety of clinically relevant molecules, like nucleic acids, viruses, bacteria, cancer antigens, pharmaceuticals and narcotic drugs, toxins, contaminants, as well as entire cells in various sensing media, ranging from buffers to more complex environments such as urine, blood or sputum. Thus, the latest advancements reviewed in this paper hold tremendous potential for the application of nanomaterials in the early screening of diseases and point-of-care testing

Distributed environmental monitoring

With increasingly ubiquitous use of web-based technologies in society today, autonomous sensor networks represent the future in large-scale information acquisition for applications ranging from environmental monitoring to in vivo sensing. This chapter presents a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed

Ionic liquids - inherent sensing and transduction of metal ion complexation

Ionic Liquids (IL’s) - being organic salts that are liquid at room temperature, display inherent ionic conductivity and a wide electrochemical window. This has led to their inevitable incorporation into electrochemical sensing techniques1. Radio Frequency (RF) detection provides a technique which can monitor conductivity wirelessly, but also has the required sensitivity and is non-invasive on the sample. We have used the IL trihexyltetradecylphosphonium dicyanamide[P6,6,6,14][DCA] which can easily be incorporated and solidified into a polymeric membrane. The resulting clear, homogenous membrane shows an optical response upon co-ordination to the metal ions Cu2+(yellow)and Co2+ (blue), and both ions simultaneously (green). RF can not only discriminate between the coordinated and noncoordinated membranes, but also between the individual co-ordinated membranes. The resultant downward trend in conductivity has been validated by Electrochemical Impedance Spectroscopy (EIS) and by X-Ray Flourescence (XRF). XRF shows that the results obtained from RF and EIS are directly related to the binding selectivity of the ligand [DCA]-. IL’s can bind to a variety of heavy metal ions and other important target analytes such as CO2.2 If a drop in conductivity can be presumed upon binding to an analyte, then the inherent conductivity properties of IL’s could be exploited in future electrochemical sensing. 1 . D. Wei., Anal. Chim. Acta. 2008, 607, 126-135 2 . E. Bates., J. Am. Chem. Soc,200

Fully Integrated Biochip Platforms for Advanced Healthcare

Recent advances in microelectronics and biosensors are enabling developments of innovative biochips for advanced healthcare by providing fully integrated platforms for continuous monitoring of a large set of human disease biomarkers. Continuous monitoring of several human metabolites can be addressed by using fully integrated and minimally invasive devices located in the sub-cutis, typically in the peritoneal region. This extends the techniques of continuous monitoring of glucose currently being pursued with diabetic patients. However, several issues have to be considered in order to succeed in developing fully integrated and minimally invasive implantable devices. These innovative devices require a high-degree of integration, minimal invasive surgery, long-term biocompatibility, security and privacy in data transmission, high reliability, high reproducibility, high specificity, low detection limit and high sensitivity. Recent advances in the field have already proposed possible solutions for several of these issues. The aim of the present paper is to present a broad spectrum of recent results and to propose future directions of development in order to obtain fully implantable systems for the continuous monitoring of the human metabolism in advanced healthcare applications

Optimization of design parameters for spacecraft nickel-cadmium cells containing recombination and control electrodes Quarterly report

Cycle capability of electrochemical cells built with oxygen recombination and oxygen sensing control electrode

Electrochemical Sensors with Screen Printed Ag|AgCl|KCl Reference Electrodes

This paper presents the printed thick film Ag|AgCl|KCl reference electrodes for electrochemical or biosensors application and their electrochemical and analytical performance. The reference electrode exhibits a stable potential against standard glass reference electrode with a potential difference of 5 mV in the deionized water. The anodic and cathodic peak current of the electrode increase with the increase in scan rate in the range of 25-150 mVs-1. The open circuit potential response of thick film reference electrode in the NaCl concentrations range (30-100 mM) was measured and it shows a stable potential in each test solution. The fabricated reference electrode shows an excellent application for an electrochemical pH sensor