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

A colorimetric CMOS-based platform for rapid total serum cholesterol quantification

Elevated cholesterol levels are associated with a greater risk of developing cardiovascular disease and other illnesses, making it a prime candidate for detection on a disposable biosensor for rapid point of care diagnostics. One of the methods to quantify cholesterol levels in human blood serum uses an optically mediated enzyme assay and a bench top spectrophotometer. The bulkiness and power hungry nature of the equipment limits its usage to laboratories. Here, we present a new disposable sensing platform that is based on a complementary metal oxide semiconductor process for total cholesterol quantification in pure blood serum. The platform that we implemented comprises readily mass-manufacturable components that exploit colorimetric changes of cholesterol oxidase and cholesterol esterase reactions. We have shown that our quantification results are comparable to that obtained by a bench top spectrophotometer. Using the implemented device, we have measured cholesterol concentration in human blood serum as low as 29 μM with a limit of detection at 13 μM, which is approximately 400 times lower than average physiological range, implying that our device also has the potential to be used for applications that require greater sensitivity

Terahertz Imagers Based on Metamaterial Structures Monolithically Integrated in Standard CMOS Technologies

Silicon complementary metal oxide semiconductor (CMOS) technologies are arguably the most important asset in the world of electronics. Focal plane arrays (FPAs) are one of the driving forces in the revolution of low-cost, mass produced, compact, and high-resolution imaging devices. The importance of these imaging systems in the visible spectrum has highlighted the need of their implementation into other significant electromagnetic regions such as infrared (IR) and Terahertz (THz). The unique characteristics of THz waves make them ideal for a variety of important applications ranging from security and medical imaging, explosive and drug detection, and non-destructive quality control testing. These applications are possible due to the non-ionizing nature of THz radiation, its transparency to many non-conductive materials, and distinctive spectroscopic fingerprints of a vast number of substances. Current THz imaging systems are usually restricted to laboratory use due the lack of compact, portable and roomtemperature operated sources and detectors. Therefore, the implementation of CMOS based THz detectors is key to promote the exploitation of low-cost, room-temperature, high-resolution, highly sensitive, and portable THz imaging systems. Here we present the monolithic integration of two types of THz FPAs fabricated in a standard 180 nm CMOS process. The imagers are composed of THz metamaterials (MM) absorbers coupled to a microbolometer, either vanadium oxide (VOx) or silicon pn diode, integrated with readout electronics to form 64 x 64 CMOS FPAs. The suitability of THz imagers for stand-off imaging of concealed objects was demonstrated in transmission mode by capturing images of metallic objects hidden in a manila envelope

Case-Based Approach to Teaching Intermediate Accounting: Addressing Faculty Concerns and Competency/Assurance of Learning Requirements

The authors propose the use of a fully integrated case approach to replace the traditional pedagogy of: read the chapter, listen to a lecture, do homework, then parrot back on an exam what was ‘remembered’. Students working in teams develop their ability to: analyze financial statement data, research new issues encountered, analyze their research results as it applies to client issues, and determine the impact on client financial statements including required disclosures. Administrators will be provided with a means to evaluate achievement of competencies and assurance of learning requirements including communication skills, critical thinking, decision analysis, and quantitative mastery of the subject matter. Faculty can assist students in developing both written and oral communication skills through playing role of: corporate controller, CPA firm partner, and corporate stockholder at company’s annual stockholders’ meeting. Concerns of free-riders among the student teams and academic integrity issues involving disclosure of case solutions are addressed

Exercise apparatus

An apparatus and method for exercising whereby the user is supported by various mechanisms in such as way that the user's shoulder area is free to translate and rotate; the user's pelvic area is free to translate and rotate; or in any combination

An integrated circuit for chip-based analysis of enzyme kinetics and metabolite quantification

We have created a novel chip-based diagnostic tools based upon quantification of metabolites using enzymes specific for their chemical conversion. Using this device we show for the first time that a solid-state circuit can be used to measure enzyme kinetics and calculate the Michaelis-Menten constant. Substrate concentration dependency of enzyme reaction rates is central to this aim. Ion-sensitive field effect transistors (ISFET) are excellent transducers for biosensing applications that are reliant upon enzyme assays, especially since they can be fabricated using mainstream microelectronics technology to ensure low unit cost, mass-manufacture, scaling to make many sensors and straightforward miniaturisation for use in point-of-care devices. Here, we describe an integrated ISFET array comprising 216 sensors. The device was fabricated with a complementary metal oxide semiconductor (CMOS) process. Unlike traditional CMOS ISFET sensors that use the Si3N4 passivation of the foundry for ion detection, the device reported here was processed with a layer of Ta2O5 that increased the detection sensitivity to 45 mV/pH unit at the sensor readout. The drift was reduced to 0.8 mV/hour with a linear pH response between pH 2 – 12. A high-speed instrumentation system capable of acquiring nearly 500 fps was developed to stream out the data. The device was then used to measure glucose concentration through the activity of hexokinase in the range of 0.05 mM – 231 mM, encompassing glucose’s physiological range in blood. Localised and temporal enzyme kinetics of hexokinase was studied in detail. These results present a roadmap towards a viable personal metabolome machine