A contact lens (CL) biosensor for in situ monitoring of tear glucose was fabricated and tested. Biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer and polydimethyl siloxane (PDMS) ...were employed as the biosensor material. The biosensor consists of a flexible Pt working electrode and a Ag/AgCl reference/counter electrode, which were formed by micro-electro-mechanical systems (MEMS) technique. The electrode at the sensing region was modified with glucose oxidase (GOD). The CL biosensor showed a good relationship between the output current and glucose concentration in a range of 0.03–5.0
mM, with a correlation coefficient of 0.999. The calibration range covered the reported tear glucose concentrations in normal and diabetic patients. Also, the CL biosensor was applied to a rabbit for the purpose of tear glucose monitoring. The basal tear glucose was estimated to 0.11
mM. Also, the change of tear glucose induced by the change of blood sugar level was assessed by the oral glucose tolerance test. As a result, tear glucose level increased with a delay of 10
min from blood sugar level. The result showed that the CL biosensor is expected to provide further detailed information about the relationship between dynamics of blood glucose and tear glucose.
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•Microsize capsule with FePt network shell was developed for bead-based immunoassay.•Mechanical stability of microcapsule was improved by double-layered FePt shell.•FePt microcapsules ...are promising solid support to immobilize antibodies.
Porous FePt microcapsules are fabricated for use in bead-based immunoassay technologies, that generally use magnetic spheres to immobilize biomolecules on their surface. The magnetic capsules can be used to carry assay reagents to reduce the time required to perform immunoassay processes, and microsize capsules are easier to manipulate magnetically than nanosize ones. Silica particles of approximately 2.5 μm diameter are used as templates and modified with poly(ethyleneimine) (PEI), which enables FePt nanoparticles to accumulate selectively on the template particles and an FePt shell to be formed by a polyol process. To increase the mechanical stability of the FePt nanoparticle assembly shell, a double-layered FePt nanoparticle assembly is fabricated by repeating the modification process of PEI and the synthesis process of FePt nanoparticles, resulting in the fabrication of magnetic capsules with a three-dimensional structure. We further investigate the ability of magnetic capsules to immobilize antibodies on their surface. Gold nanoparticles are used as linkers between the magnetic microcapsules and antibodies. The antibodies are successfully immobilized on the surface of the developed microsize FePt capsules.
A new single-cell microarray chip was designed and developed to separate and analyze single adherent and non-adherent cancer cells. The single-cell microarray chip is made of polystyrene with over ...60,000 microchambers of 10 different size patterns (31-40 µm upper diameter, 11-20 µm lower diameter). A drop of suspension of adherent carcinoma (NCI-H1650) and non-adherent leukocyte (CCRF-CEM) cells was placed onto the chip, and single-cell occupancy of NCI-H1650 and CCRF-CEM was determined to be 79% and 84%, respectively. This was achieved by controlling the chip design and surface treatment. Analysis of protein expression in single NCI-H1650 and CCRF-CEM cells was performed on the single-cell microarray chip by multi-antibody staining. Additionally, with this system, we retrieved positive single cells from the microchambers by a micromanipulator. Thus, this system demonstrates the potential for easy and accurate separation and analysis of various types of single cells.
A 2-dimensional imaging system was constructed and applied in measurements of gaseous ethanol emissions from the human palm. This imaging system measures gaseous ethanol concentrations as intensities ...of chemiluminescence by luminol reaction induced by alcohol oxidase and luminol-hydrogen peroxide-horseradish peroxidase system. Conversions of ethanol distributions and concentrations to 2-dimensional chemiluminescence were conducted on an enzyme-immobilized mesh substrate in a dark box, which contained a luminol solution. In order to visualize ethanol emissions from human palm skin, we developed highly sensitive and selective imaging system for transpired gaseous ethanol at sub ppm-levels. Thus, a mixture of a high-purity luminol solution of luminol sodium salt HG solution instead of standard luminol solution and an enhancer of eosin Y solution was adapted to refine the chemiluminescent intensity of the imaging system, and improved the detection limit to 3 ppm gaseous ethanol. The highly sensitive imaging allows us to successfully visualize the emissions dynamics of transdermal gaseous ethanol. The intensity of each site on the palm shows the reflection of ethanol concentrations distributions corresponding to the amount of alcohol metabolized upon consumption. This imaging system is significant and useful for the assessment of ethanol measurement of the palmar skin.
Humic acid-coated goethite nanoparticles (HA-GoeNPs) have been recently proposed as an effective reagent for the in situ nanoremediation of contaminated aquifers. However, the effective dosage of ...these particles has been studied only at laboratory scale to date. This study investigates the possibility of using HA-GoeNPs in remediation of real field sites by mimicking the injection and transport of HA-GoeNPs under realistic conditions. To this purpose, a three-dimensional (3D) transport experiment was conducted in a large-scale container representing a heterogeneous unconfined aquifer. Monitoring data, including particle size distribution, total iron (Fetot) content and turbidity measurements, revealed a good subsurface mobility of the HA-GoeNP suspension, especially within the higher permeability zones. A radius of influence of 2 m was achieved, proving that HA-GoeNPs delivery is feasible for aquifer restoration. A flow and transport model of the container was built using the numerical code Micro and Nanoparticle transport Model in 3D geometries (MNM3D) to predict the particle behavior during the experiment. The agreement between modeling and experimental results validated the capability of the model to reproduce the HA-GoeNP transport in a 3D heterogeneous aquifer. Such result confirms MNM3D as a valuable tool to support the design of field-scale applications of goethite-based nanoremediation.
A non-invasive breath gaseous ethanol imaging system with an exhaled breath flow rate control has been developed. The system offers straight-forward, rapid, and painless sampling from patients, and ...can be applied to diagnose diseases. The system provides an image of ethanol concentration using chemiluminescence (CL) from an enzyme-immobilized support. The system measures ethanol concentrations as intensities of CL by luminol reaction induced by alcohol oxidase and horseradish peroxidase–luminol–hydrogen peroxide system. The spatio-temporal change in CL generates by ethanol in an exhaled breath is detected by an electron multiplier EM-CCD camera and analyzed. An ethanol skin patch test, a simple method of indicating aldehydehydrogenase 2 (ALDH2), is performed on healthy volunteers. Breath samples from volunteers with ALDH2(+) and ALDH2(−) are analyzed. The exhaled breath flow rate control unit can control and optimize the naturally unstable flow rate of human breath without a gas sampling bag. The coefficient of variance in the exhaled breath flow rate is estimated at 2.8% at a flow rate of 200mL/min. Exhaled gaseous ethanol obtained from volunteers is visualized and analyzed over a period of 300min following the oral administration of ethanol at 0.4g/kg body weight. A peak in the exhaled breath ethanol concentration appears at 30min for both ALDH2(+) and ALDH2(−) volunteers, the breath ethanol concentration then gradually decreases over the remainder of the 300min.
Dermatophagoides farinae allergen (Der f1) is one of the most important indoor allergens associated with allergic diseases in humans. Mite allergen Der f1 is usually associated with particles of high ...molecular weight; thus, Der f1 is generally present in settled dust. However, a small quantity of Der f1 can be aerosolized and become an airborne component. Until now, a reliable method of detecting airborne Der f1 has not been developed. The aim of this study was to develop a fiber-optic chemifluorescent immunoassay for the detection of airborne Der f1. In this method, the Der f1 concentration measured on the basis of the intensity of fluorescence amplified by an enzymatic reaction between the labeled enzyme by a detection antibody and a fluorescent substrate. The measured Der f1 concentration was in the range from 0.49 to 250ng/ml and a similar range was found by enzyme-linked immunosorbent assay (ELISA). This method was proved to be highly sensitive to Der f1 compared with other airborne allergens. For the implementation of airborne allergen measurement in a residential environment, a bioaerosol sampler was constructed. The airborne allergen generated by a nebulizer was conveyed to a newly sampler we developed for collecting airborne Der f1. The sampler was composed of polymethyl methacrylate (PMMA) cells for gas/liquid phases and some porous membranes which were sandwiched in between the two phases. Der f1 in air was collected by the sampler and measured using the fiber-optic immunoassay system. The concentration of Der f1 in aerosolized standards was in the range from 0.125 to 2.0mg/m3 and the collection rate of the device was approximately 0.2%.
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•Novel fiber-optic chemifluorescent immunoassay system and bioaerosol sampler is proposed.•The immunoassay system is constructed by simple components and has high-sensitivity and selectivity for the house dust mite allergen.•The developed bioaerosol sampler needs lower impaction stress and lower power consumption than any other sampler for aerosol particles.•This work presents that the sampler and the immunoassay system have ability to apply the measurement of allergen in the real house dust in the indoor air.
A high sensitive fiber-optic biochemical gas sensor (bio-sniffer) for sub-parts-per-billion (sub-ppb) monitoring of formaldehyde (FA) vapor was constructed and tested. The bio-sniffer measures ...formaldehyde vapor as fluorescence of reduced nicotinamide adenine dinucleotide (NADH), which is the product of formaldehyde dehydrogenase (FALDH) reaction. An ultraviolet light emitting diode (UV-LED) with peak emission of 335
nm was employed as an excitation light source. Emission of the UV-LED was introduced to the optode through an optical fiber and fluorescence of NADH was picked up coaxially at the optode. In order to achieve sub-ppb sensitivity, two types of detectors (a spectrometer and a photomultiplier tube (PMT)) were tested. The reaction system was also improved. Aldehyde dehydrogenase (ALDH), which is more active with formaldehyde, was first tested instead of FALDH. The product of ALDH reaction was again oxidized by formate dehydrogenase (FDH) to enhance production of NADH. As a result of these improvements, real-time monitoring of FA was performed with a detection limit of 0.75
ppb, which is comparative to chromatographic methods. Such a high sensitive monitoring method is expected to improve the quality of indoor air management.
A fiber-optic biochemical gas sensor (bio-sniffer) for assessment of indoor formaldehyde (FA) is fabricated and tested in monitoring of FA degradation by TiO 2 . The biosniffer measures FA vapor as ...fluorescence of reduced nicotinamide adenine dinucleotide (NADH), which is the product of enzymatic reaction of FA dehydrogenase (FALDH). Usually, an enzyme loses its specific activity in the gas phase. This makes biochemical gas monitoring difficult. We employ a microflow-cell with a FALDHimmobilized membrane to prevent the FALDH from deactivation at the optode. An ultraviolet light-emitting diode (UV-LED) with peak emission of 335 nm is employed as an excitation light source. Emission of the UV-LED is introduced to the optode through an optical fiber and fluorescence of NADH is picked up coaxially at the optode. To improve the sensitivity, a multi-LED light source is introduced instead of the previously reported system. A photomultiplier tube is utilized as a photodetector. Continuous FA monitoring with biochemical method is successfully conducted with high selectivity at subppb level. Owing to the improved excitation source, the detection limit is improved to 750 ppt. A real-sample test is also carried out using a photocatalytic titania. A standard gas is flowed into a cell, in which photocatalyst glasses are located, and the FA level is measured using the biosniffer. Therefore, degradation of FA by the catalytic reaction of titania is monitored as reduction of FA in real time. According to the results, it is expected to be useful in fast and convenient monitoring of indoor FA.
•Granular metallic iron (Fe0) is a powerful material for water treatment.•Methylene blue (MB) discoloration potentially eases testing Fe0/H2O systems.•Fe0/sand systems as impacted by MnO2 addition is ...described using MB discoloration.•Documented trends are satisfactorily reproduced and thoroughly discussed.•MB discoloration for characterizing further operational factors is recommended.
The impact of sand on the efficiency of metallic iron (Fe0) at discoloring a methylene blue (MB) solution in the presence of MnO2 was characterized. The MB initial concentration was 10mgL−1. 22.0mL of this solution was used for each test. Investigated systems were: (i) Fe0 alone, (ii) MnO2 alone, (iii) sand alone, (iv) a sand/MnO2 mixture, and (v) Fe0/sand/MnO2 mixtures with three different natural MnO2-bearing minerals. Tested material loadings varied from 0.0 to 45.0gL−1. A commercial Fe0 and three natural MnO2 materials (Manganite, Psilomelane and X-MnO2) were tested in shaken experiments at 75rpm for 14days. The documented delay of MB discoloration by Fe0 in the presence of MnO2 was the evaluation criterion. This characteristic discoloration delay was observed for all tested materials at MnO2 loadings <6gL−1. For higher MnO2 loadings, the Fe0/Manganite/sand system was more efficient than the Fe0/sand system. The largest extend of the delay of MB discoloration was observed in the Fe0/X-MnO2/sand system. This observation delineated the crucial importance of characterizing the intrinsic reactivity of tested MnO2 materials for comparable results. This study highlighted the crucial importance of experimental conditions as major source of confusing/conflicting reports.
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