An analyte monitor includes a sensor, a sensor control unit, and a display unit. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The sensor control unit typically has a housing adapted for placement on skin and is adapted to receive a portion of an electrochemical sensor. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. A transmitter is disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor. The display unit has a receiver for receiving data transmitted by the transmitter of the sensor control unit and a display coupled to the receiver for displaying an indication of a level of an analyte. The analyte monitor may also be part of a drug delivery system to alter the level of the analyte based on the data obtained using the sensor.

Analyte Monitoring Device And Methods Of Use

Wearable biosensors are garnering substantial interest due to their potential to provide continuous, real-time physiological information via dynamic, noninvasive measurements of biochemical markers in biofluids, such as sweat, tears, saliva and interstitial fluid. Recent developments have focused on electrochemical and optical biosensors, together with advances in the noninvasive monitoring of biomarkers including metabolites, bacteria and hormones. A combination of multiplexed biosensing, microfluidic sampling and transport systems have been integrated, miniaturized and combined with flexible materials for improved wearability and ease of operation. Although wearable biosensors hold promise, a better understanding of the correlations between analyte concentrations in the blood and noninvasive biofluids is needed to improve reliability. An expanded set of on-body bioaffinity assays and more sensing strategies are needed to make more biomarkers accessible to monitoring. Large-cohort validation studies of wearable biosensor performance will be needed to underpin clinical acceptance. Accurate and reliable real-time sensing of physiological information using wearable biosensor technologies would have a broad impact on our daily lives.

Wearable biosensors for healthcare monitoring.

http://cau.ac.kr/~jjang14/BioMEMS/Lazcka_BSBE_Pathogen_Detection_Review_2006.pdf

Pathogen detection: a perspective of traditional methods and biosensors.

Glucose oxidase: an ideal enzyme

Generation of reactive oxygen species (ROS) by the mitochondrial electron transport chain (ETC), which is composed of four multiprotein complexes named complex I-IV, is believed to be important in the aging process and in the pathogenesis of neurodegenerative diseases such as Parkinson's disease. Previous studies have identified the ubiquinone of complex III and an unknown component of complex I as the major sites of ROS generation. Here we show that the physiologically relevant ROS generation supported by the complex II substrate succinate occurs at the flavin mononucleotide group (FMN) of complex I through reversed electron transfer, not at the ubiquinone of complex III as commonly believed. Indirect evidence indicates that the unknown ROS-generating site within complex I is also likely to be the FMN group. It is therefore suggested that the major physiologically and pathologically relevant ROS-generating site in mitochondria is limited to the FMN group of complex I. These new insights clarify an elusive target for intervening mitochondrial ROS-related processes or diseases.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.0022-3042.2002.00744.x

Generation of reactive oxygen species by the mitochondrial electron transport chain

A new enzyme electrode for the determination of L-asparagine is constructed by chemical immobilization of L-aspartase [E.C. 4.3.1.1] on an ammonia-gas-sensing probe. L-Asparagine was determined over a concentration range of 1.6 × 10−5 to 1.5 × 10−3 M with a subnerstian response of -51 mV/decade. The electrode was stable for more than 30 days. The effect of pH, substrate and metal activator concentrations, amount of immobilized enzyme, and interferents on the electrode response are reported.

Potentiometric Determination of L-Asparagine with an Enzymatic Electrode

In articles by Kokalas et al.1,2 studies were made of the interaction of FeCl3 with diisopropyl methylphosphonate (DIMP), diethyl ethylphosphonate (DEEP), and dimethyl methyl phosphonate (DMMP) and structures were proposed for the reaction products. When the reactions are run under much milder conditions, there is much evidence3–5 to support a different mechanism than that proposed by Kokalas and an altogether different structure of the complexes formed. In the structures proposed by Kokalas et al. the iron atom is surrounded by six oxygen atoms and these are the only bonding atoms to the iron. But on the other hand, in donor-acceptor complexes as are formed in chemisorption reactions,3–5 some of these sites are filled by chloride ions and this difference should be ascertained quite easily by far-infrared spectroscopy. It was the purpose of this study to look at the far-infrared data and either further substantiate the structures proposed or to propose new ones.

A Far-Infrared Study of the Structures of Tris(Methyl Methyl Phosphonate) Iron(III), Tris(EthylEthylphosphonate) Iron(III), and Tris(IsopropylMethylphosphonate) Iron(III)

8 An amperometric immunosensor for the specific and simple detection of 3,4-methylenedioxyamphetamine (MDA) and its analogues, 3,4methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) in saliva and urine was developed. A direct competitive assay in which free analyte and horseradish peroxidase labelled species were simultaneously added to an immobilised polyclonal antibody was employed. Both MDA and MDMA could be labelled with the enzyme and the use of an MDMA–HRP tracer greatly enhanced the sensitivity of the assay. Amperometric detection was performed at +100 mV versus Ag/AgCl, using tetramethylbenzidine (TMB)/H2O2 as s t c s a u p m 9

Development of a screen-printed immunosensor for the rapid and non-invasive detection of ecstasy in saliva

The isolation, purification, and analytical use of enzymes from microbial sources are described: L-lysine decarboxylase fromE. coli, L-methionine ammonia lyase fromPseudomonasovalis, nitrate reductase fromChlorella vulgaris, nitrite reductase fromAzotobacter chroococcum, sulfate reductase fromDesulvibrio desulficans, and creatininase fromPseudomonas. Both electrochemical, fluorometric, and spectrophotometric methods are proposed for the assay of enzyme activity, and specific, sensitive, fast, and inexpensive methods are described for the assay of 10-1-10-1 M concentrations of L-lysine, L-methionine, nitrate, nitrite, creatinine, and triglycerides.

Fluorometric and electrochemical methods for assay of biological and environmental substances

In recent years, emphasis on the treatment of myocardial infarction is gradually shifting away from observation and documentation toward prompt management procedures. Early detection and confirmation of coronary occlusion by physical or chemical tests can provide the doctors with reliable information in planning an early operation in order to avoid future tissue damage. Most of the tests used in the past are for documentation. In general, EKG’s are not useful for early detection of myocardial infarcts since the electrocardiographic changes usually occur after onset. Many chemical tests are neither specific nor sensitive in detecting myocardial distress. Among the chemical tests, the measurement of CK-MB, the cardiac specific isoenzyme, appears to be the most specific and reliable procedure to obtain confirmative information for early diagnosis of acute myocardial infarction.

George G. Guilbault

Papers

Potentiometric Determination of L-Asparagine with an Enzymatic Electrode

A Far-Infrared Study of the Structures of Tris(Methyl Methyl Phosphonate) Iron(III), Tris(EthylEthylphosphonate) Iron(III), and Tris(IsopropylMethylphosphonate) Iron(III)

Development of a screen-printed immunosensor for the rapid and non-invasive detection of ecstasy in saliva

Fluorometric and electrochemical methods for assay of biological and environmental substances

Immunochemical Determination of Creatine Kinase Isoenzyme-MB