Biosensors

Measuring blood hematocrit noninvasively is reviewed in this paper. Although there is an inclination to
measure the hematocrit by determining the bioelectrical impedance of the blood, in vitro experimental
methods still remain practically inapplicable. The blood sample size is determined when blood samples
are examined. Determining the impedance and volume of blood is the biggest challenge in measuring
the hematocrit noninvasively without drawing a blood sample. Calculating the blood impedance in vivo
requires developing an impedance measurement using a multi-frequency method and also calculating
the change in pressure simultaneously during the heart’s pulsatile cycle.

High-level composite, ab initio and density functional theory (DFT) procedures have been employed to study O–H bond dissociation energies (BDEs), as well as radical stabilization energies (RSEs) in the oxygen-centred radicals that are formed in the dissociation of the O–H bonds. Benchmark values are provided by Wn results up to W3.2 and W4.x. We are able to recommend revised BDE values for FO–H (415.6 ± 3 kJ mol–1), MeC(O)O–H (459.8 ± 6 kJ mol–1) and CF3CH2O–H (461.9 ± 6 kJ mol–1) on the basis of high-level calculations. We find that Gn-type procedures are generally reliable and cost-effective, and that some contemporary functionals and double-hybrid DFT procedures also provide adequate O–H BDEs/RSEs. We note that the variations in the O–H BDEs are associated with variations in the stabilities of not only the radicals but also the closed-shell precursor molecules. Most substituents destabilize both species, with σ-electron-withdrawing groups having larger destabilizing effects, whil...

Emotion recognition is one of the important highlights of human emotional intelligence and has long been studied to be incorporated with machine intelligence argued to make machines even more intelligent. This paper aims to contribute to this field of study by enabling machines to recognize emotion from facial electromyogram (EMG) signals. This includes a compilation of the groups attempt to recognize basic facial expressions namely happy, angry, and sad through the use of EMG signals from facial muscles. The group extracted features from the three EMG signals from the face of two human subjects, a male and a female, and analyzed these features to serve as feature templates. Using a minimum-distance classifier, recognition rates exceeded the target accuracy - 85 percent - reaching 94.44 percent for both the male and female subjects.

The pharmaceutical industry is facing enormous challenges due to high drug attribution rates. For the past decades, novel methods have been developed for safety and efficacy testing, as well as for improving early development stages. screening methods for drug-receptor binding are considered to be good alternatives for decreasing costs in the identification of drug candidates. However, these methods require lengthy and troublesome labeling steps. Biosensors hold great promise due to the fact that label-free detection schemes can be designed in an easy and low-cost manner. In this paper, for the first time in the literature, we aimed to compare the potential of label-free optical and impedimetric electrochemical biosensors for the screening of antipsychotic drugs (APDs) based on their binding properties to dopamine receptors. Particularly, we have chosen a currently-used atypical antipsychotic drug (Buspirone) for investigating its dopamine D3 receptor (D3R) binding properties using ...

Recently, a novel approach to a highly sensitive and quantitative detection of rare earth element (REE) ions including La3+, Eu3+ and Tb3+, by the polymerase chain reaction (PCR) technique, has been reported. The detection of REE ions is based on the catalytic nature of REE ions targeting the deoxyribonucleic acid (DNA), thus monitoring of the ions can be achieved by reading the level of intact DNA by PCR. Despite of its high sensitivity (at ppb to ppt levels), the conventional PCR-based REE detection protocol requires certain length of time (1-2 hours). In the present study, we modified the PCR-based REE detection protocols by employing the high-speed PCR, and performed the automated and rapid detection of La3+ in small-sized aqueous samples within 5min.

The present work is the first work that includes the use of glycine (Gly), lysine (Lys) and glutamic acid
(Glu) modified clay mineral matrices in the biosensors. For this purpose, initially, Gly, Lys and Glu were
intercalated with montmorillonite (Mt), thus, various modified Mts were obtained. These modified
materials were then characterized via X-ray diffraction, Fourier transform infrared spectroscopy, zeta
potential and thermal gravimetric analysis (TGA/DTG) and scanning electron microscopy (SEM). In order
to investigate the applicability of amino acid modified clay minerals in biosensor area, glucose oxidase
(GOx) was selected as the model enzyme and GOx based biosensor was prepared. After immobilizing the
enzyme with amino acid modified Mt onto a glassy carbon electrode, working conditions like pH and
modifier type were optimized. Among the modified Mts, Gly-Mt was the optimum clay mineral type and
pH 4.0 was the optimum pH value. Then analytical characteristics were examined under optimum
experimental conditions. Linear range of optimum sensor design was 0.1 – 1.0 mM within kinetic
parameters of immobilized enzyme Km
app= 0.7 mM, Imax =107.8 nA. Finally, developed biosensor was
applied to real samples where the results were compared with a spectrophotometric reference method.

This paper describes an action research project based on the process of designing the visualisation of heart and breath rate data for the interactive artwork Cardiomorphologies. The project aimed to realise the affective goals of the artist as closely as possible by studying the audience experience of the visualisations and incorporating the findings into an iterative design process. The qualities of richness and ambiguity were found to contribute to the achievement of the artists' two major aims: 1) to create a sense of ...

The detection of water contamination with Legionella pneumophila is of critical importance to manufacturers of water processing equipment and public health entities dealing with water networks and distribution systems. Detection methods based on polymerase chain reaction or biosensor technologies require preconcentration steps to achieve attractive sensitivity levels. Preconcentration must also be included in protocols of automated collection of water samples by systems designed for quasi-continuous monitoring of remotely located water reservoirs for the presence of L. pneumophila. We designed and characterized a water sampling module for filtration and backwashing intended for analysis of low-to-medium contaminated water, typically with L. pneumophila bacteria not exceeding 50 colony-forming units per milliliter. The concentration factors of 10× and 21× were achieved with 0.22 and 0.45 µm filters, respectively, for samples of bacteria prepared in clean saline solutions. However, a ...

Aim. Comparison of the IgG-binding activity of recombinant Staphylococcal protein A with introduced C-terminal cysteine residue (SPA-Cys) or goat anti-human IgG antibodies (anti-IgG) after their immobiliza-tion on a gold sensor surface of surface plasmon resonance (SPR) spectrometer. Methods. SPA-Cys or anti-IgG were immobilized on a gold sensor surface to form two variants of a bioselective element of the immu-nosensor. SPR spectrometry was used for the detection of IgG-binding activity of the immobilized proteins. Results. The SPR sensor response to the immobilization of anti-IgG was more than two times higher than that to the immobilization of SPA-Cys. However, there is almost the double advantage for SPA-Cys in the number of immobilized molecules. Moreover, the bioselective element of the immunosensor based on SPA-Cys showed a much better capability of binding IgG than the bioselective element based on anti-IgG. Conclusions. Comparison of immobilization of SPA-Cys or anti-IgG on the sensor surface of SPR spectrometer, and the interactions of immobilized proteins with human IgG demonstrated obvious advantages of SPA-Cys. K e y w o r d s: antibodies, recombinant Staphylococcal protein A, protein immobilization, immunosensor, surface plasmon resonance.

Glucose sensors are potentially useful tools for monitoring the glucose concentration in cell culture medium. Here, we present a new, low-cost, and reproducible sensor based on a cellulose-based material, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized-cellulose nanocrystals (CNCs). This novel biocompatible and inert nanomaterial is employed as a polymeric matrix to immobilize and stabilize glucose oxidase in the fabrication of a reproducible, operationally stable, highly selective, cost-effective, screen-printed glucose sensor. The sensors have a linear range of 0.1–2 mM (R2 = 0.999) and a sensitivity of 5.7 ± 0.3 µA cm−2∙mM−1. The limit of detection is 0.004 mM, and the limit of quantification is 0.015 mM. The sensor maintains 92.3 % of the initial current response after 30 consecutive measurements in a 1 mM standard glucose solution, and has a shelf life of 1 month while maintaining high selectivity. We demonstrate the practical application of the sensor by monitoring the g...

Aquaculture is globally the fastest growing primary industry (>6% per annum). Smart-farming, using sentinel animals equipped with miniature biosensors alongside environmental sensors and farm management systems has the potential to revolutionize all sectors of the industry. Real-time animal and environmental monitoring together, will support improved farm management decisions, animal welfare, social awareness and consequently sustainable productivity. Biosensors that monitor the physiology and behavior of sentinel animals provide information on animal well-being and its responses to environmental change and management actions. In turn, this information is extrapolated to help with stock management decisions. This paper introduces the sentinel animal concept to commercial aquaculture with a case study using oysters fitted with biosensors that measure heart rate, and other parameters. We demonstrate how sentinel animals can be effectively integrated alongside environmental sensors ...

The advances in studies of trace metal speciation and bioavailability since Mark Florence’s 1982 review of the topic, published in Talanta, have been comprehensively reviewed. While the relative merits of kinetic and equilibrium approaches are still being determined, advances in the applications of stripping voltammetry, including the application of microelectrodes and an appreciation of detection windows in both CSV and ASV, have been matched by the introduction of new dynamic techniques including diffusive gradients in thin films (DGTs), permeation liquid membranes (PLMs), and improved applications of chelating resins. There have also been improvements in equilibrium techniques such as ion-selective electrodes and Donnan dialysis. The ability of geochemical speciation models to predict metal complexation by natural organic matter has greatly improved, yet the models still require validation against field measurements. More reliable and relevant bioassays have been developed using ...

While place-based methods are increasingly being used to explore why place matters for health, how places matter for mental health and psychological wellness is less understood. Overall, approaches that consider community, environmental, and neighborhood-level factors have been taken up to a lesser extent by psychologists. Yet methods that situate human behavior within a spatial context have the potential to expand psychological and interdisciplinary inquiry aimed at improving mental and cognitive health. This article presents a brief overview of one type of mobile method, the go-along walk, that can be used with a variety of technologies and complementary methods to better understand how individuals respond to places and environmental stimuli, including place-based exposures. Implications for broadening the range of research questions and translational applications are discussed.

Iron deficiency (ID) is an urgent public health problem that has devastating effects on maternal and child health. However, due to poor access and affordability, screening and diagnosis for ID is often limited to proxy hemoglobin measurements alone. Here, we report the development and validation of ironPhone, a mobile-device coupled portable diagnostics for quantification of serum ferritin concentrations, an iron status biomarker, within a few minutes, from a drop of fingerprick blood. The ironPhone diagnostic platform comprises of a smartphone accessory, an app, and a disposable lateral flow immunoassay test strip to quantify serum ferritin. For initial validation in the lab, we optimized and evaluated the performance of ironPhone with known ferritin concentrations in spiked buffer and serum samples. Following lab validation, we performed a human validation by collecting fingerprick whole blood samples from 20 participants to assess iron status using ironPhone and compared the results with the laboratory standard IMMULITE 2000 analyzer. Findings from the ironPhone for the buffer and spiked serum samples provided a calibration curve with R 2 values of 0.97 (n=27) and 0.93 (n=12), respectively. On comparison with the laboratory standard IMMULITE analyzer in whole blood samples, a correlation of 0.92 (P < 0.0001) was observed with a sensitivity of over 90% for predicting ID (ferritin < 15.0 µg/L) via the ironPhone, demonstrating its promise for iron status assessment at the point-of-care.

Bulk characteristics and deposition of gold nanoparticles on mica modified by (PAH) was studied byUV–visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM),dynamic light scattering (DLS) and atomic force microscopy (AFM). The size of gold nanoparticles (AuNPs)was 15 nm as determined by TEM and AFM. The electrophoretic mobilities and electrokinetic chargeof particles were quantitatively evaluated for a broad range of pH and ionic strength. Using Henry’smodel, it was calculated that the zeta potential of particles varied between − 50 mV and − 80 mV forpH 2 and pH 11, respectively (at 10−2M of NaCl). Measurements of nanoparticle deposition kineticswere performed under diffusion-controlled transport conditions using AFM and SEM imaging of particlemonolayers. The influence of the bulk suspension concentration was systematically studied. Additionally,the maximum coverage of particle monolayers, which monotonically increased with ionic strength, wasdetermined by SEM. The obtained data were in agreement with theoretical predictions derived from therandom sequential adsorption (RSA) model. It was also confirmed that by varying the bulk suspensionconcentration and ionic strength one can prepare homogeneous gold particle monolayers of controlledcoverage.

Wireless biosensor applications require RF electronics to operate in immediate proximity of the body. This work investigates the effect of human body on RF circuits by simulations and measurements. Design methodology and initial design guidelines for body-worn discrete RF electronics are presented. The test structures are manufactured using printed electronics technology well suited for thin, flexible body-worn wireless sensor applications. The results indicate that in direct contact the human body significantly affects the performance of an RF circuit and needs to be considered. The research is relevant for modeling-based design of flexible body-worn wireless sensors.

Biosensors are being used for highly sensitive and selective recognition of biological macromolecules. The impedance based biosensor utilizes the electrical impedance measurements between interdigitated electrodes integrated into a microchannel containing the target cells in a suspension medium. The detection is based on measuring the change in impedance caused by the presence of bacteria. In the experimental methods an impedance analyzer was used to measure the electrical impedance. The first impedance measurement was done with the microfluidic system containing the suspension medium alone and is referred to as the control signal. The subsequent impedance measurements were performed with known concentration of Escherichia coli (E. coli) cells added to the same suspension medium. In this paper we describe the simulation of impedance measurements using the electromagnetics module of COMSOL Multiphysics TM , a commercially available modeling package.

In body biosensor networks, which may be classified as a specialized type of ad hoc networks, it is necessary to ensure the authenticity and freshness of the vital medical information. In this work, we propose security solutions to identify attacks on data freshness and preserve message integrity in these networks. We use the measurement of permissible round trip time threshold and computationally feasible authentication solution to address the security threats in the network. We have implemented a prototype framework in GloMoSim to assess and evaluate the robustness of our detection mechanism.