Pretreatment Device Research Articles

Integrated microfluidic system for electrochemical sensing of glycosylated hemoglobin

This article reports a new miniature electrochemical detection system integrating a sample pretreatment device for fast detection of glycosylated hemoglobin (HbA1C), which is a common indicator for diabetes mellitus. In this system, circular micropumps, normally closed microvalves, dielectrophoretic (DEP) electrodes, and electrochemical sensing electrode are integrated to perform several crucial processes. These processes include separation of red blood cells (RBCs), sample/reagent transportation, mixing, cell lysis, and electrochemical sensing. For the HbA1C measurement, the RBCs are separated and are collected from whole human blood by using a positive DEP force generated by the DEP electrodes. The collected RBCs are then lysed to release HbA1C for the subsequent electrochemical detection processes. Experimental data show that the RBCs are successfully separated and are collected using the developed system with a RBCs capture rate of 84.2%. The subsequent detection of HbA1C is automatically completed by utilizing electrochemical sensing electrode. The microfluidic system only consumes a sample volume of 200 μl. The entire process is automatically performed within a short period of time (10 min). The development of this integrated microfluidic system may be promising for the clinical monitoring of diabetes mellitus.

Electricity generation directly using human feces wastewater for life support system

Wastewater reuse and power regeneration are key issues in the research of bioregeneration life support system (BLSS). Microbial fuel cell (MFC) can generate electricity during the process of wastewater treatment, which might be promising to solve the two problems simultaneously. We used human feces wastewater containing abundant organic compounds as the substrate of MFC to generate electricity, and the factors concerning electricity generation capacity were investigated. The removal efficiency of total chemical oxygen demand (TCOD), Soluble chemical oxygen demand (SCOD) and NH 4 + reached 71%, 88% and 44%, respectively with two-chamber MFC when it was fed with the actual human feces wastewater and operated for 190 h. And the maximum power density reached 70.8 mW/m 2, which implicated that MFC technology was feasible and appropriate for treating human feces wastewater. In order to improve the power generation of MFC further, human feces wastewater were fermented before poured into MFC, and the result showed that fermentation pretreatment could improve the MFC output obviously. The maximum power density of MFC fed with pretreated human feces wastewater was 22 mW/m 2, which was 47% higher than that of the control without pretreatment (15 mW/m 2). Furthermore, the structure of MFC was studied and it was found that both enlarging the area of electrodes and shortening the distance between electrodes could increase the electricity generation capacity. Finally, an automatic system, controlled by time switches and electromagnetic valves, was established to process one person's feces wastewater (1 L/d) while generating electricity. The main parts of this system comprised a pretreatment device and 3 one-chamber air-cathode MFCs. The total power could reach 787.1 mW and power density could reach the maximum of about 240 mW/m 2.

One-Chip Integration of Rapid Diagnosis Infectious-Disease Chip Based on New Phenomena of DNA Trap and Denature in Nanogaps

We demonstrate the concept of simple and rapid diagnosis chips for infectious diseases by analyzing viral DNA from the plasma of patients. DNA was manipulated simply in a chip-integrated pretreatment device and nanogap array. A simple and rapid detection of target DNA by purification and hybridization with a number of DNA trapped in a pretreatment device and nanogap array was performed. T4DNA was immobilized and purified on micropillars in the pretreatment device. Purified T4DNA was further transported to the nanogap array and fixed by stretching. The fixed T4DNA was denatured into single-stranded (ss) DNA in the array. When a probe DNA was introduced into the nano-gap array to hybridize the trapped ssDNA, an intense luminescence was observed in the array. These results provide a simple and rapid detection method of target DNA of various infectious diseases.

Microfluidic Systems Integrated With a Sample Pretreatment Device for Fast Nucleic-Acid Amplification

This paper presents a new miniature reverse-transcription polymerase chain-reaction (RT-PCR) system integrating a sample pretreatment device for fast nucleic-acid amplification and diagnosis of viruses and bacteria. In the system, a two-way serpentine-shape (s-shape) pneumatic micropump and a magnetic bioseparator were developed for separation and enrichment of viruses and bacteria. This new bioseparator can also be used as microheating chambers to perform RT-PCR. Taking advantage of the specific interaction between the antibodies on the surface of magnetic beads and the surface antigens on viruses or bacteria, the target virus and bacteria were recognized and further separated and purified from the biosamples by a magnetic field generated by the bioseparator. The target purified virus/bacteria was then lysed to release ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) for the subsequent RT-PCR processes. Experimental results showed that the target virus/bacteria was successfully separated and enriched by the high specificity and selectivity of antibody-conjugated magnetic beads, and the subsequent amplification of RNA/DNA was automatically completed by utilizing the on-chip microheaters and the micro temperature sensor. The high mixing efficiency of the two-way s-shape pump and the rapid heating/cooling rate of the microheating chambers can significantly shorten the pretreatment and diagnosis processes. As a whole, the developed system may provide a powerful platform for sample pretreatment and fast disease diagnosis.

Integrated DNA Purification and Detection Device for Diagnosis of Infectious Disease

This paper demonstrates the concept of a diagnosis chip for infectious diseases caused by viruses, and especially the one-chip integration of DNA purification, trapping, and detection. We attempted to construct a DNA purification tool (DNA pre-treatment device) comprising alumina (Al2O3)-coated micro-pillars and hydrogel valves, whose function varied with the pH of washing solutions. It was found that DNA was immobilized on the micro-pillars in acidic solution, eluted in alkaline solution, and reversed by controlling the pH-dependent hydrogel valves. As a result, one-chip integration for infectious disease diagnosis combined with a DNA cleaning chip was achieved.

吸着・加熱脱着分析におけるサンプリング前処理に関する検討

For adsorption—thermal desorption analysis, three ways of gas sampling pretreatments: 1) two water impingers (“Two impingers”); 2) two water impingers and two empty impingers (“Four impingers”); 3) cooling dehumidifier with Ag column (“Cooling dehumidifier”), were compared using aliphatic organic chlorinated compounds, chlorobenzenes and chlorophenols. Since the gas pretreatment system combines gas—liquid contact, distribution of chemicals between air and water was examined by a tank analogy model employing water volume, gas volume and Henry's constant. The compounds, Henry's constant of which is relatively low (those distribute more to water than to air) such as chlorophenols can neither pass “Two impingers” nor “For impingers” efficiently, while can survive at a rate of 70 % through “Cooling humidifier”, because it does not use water. Those compounds, the water solubility of which is high, such as chloroform and dichloromethane did not pass “Four impingers” although the estimated Henry's constant is adequately large. That suggests Henry's constant estimation involves considerable error for those compounds. Pretreatment loss caused by condensation and adsorption is sensitively affected by the property and the condition of the pretreatment device, namely, tetrachlorobenzene and larger compounds were significantly lost in “Four impingers” and “Cooling dehumidifier”, while “Two impingers” can pass pentachlorobenzene efficiently. Adsorption—thermal desorption property was studied using Carbotrap C. If the suctioned gas volume is increased, the recovery loss did not show exponential decrease, but the thermal desorption chart became split two peaks, main and shoulder, and desorption velocity went slow. That suggests the chemicals has diffused into the inner of the adsorbent. For the sake of the optimization of adsorption—thermal desorption analysis, limitation of analyzed chemical to avoid instrumental memory, and sensitive detection to quick determination and down-sizing of sampled gas volume.

A novel approach and protocol for discovering extremely low‐abundance proteins in serum

The proteomic analysis of serum (plasma) has been a major approach to determining biomarkers essential for early disease diagnoses and drug discoveries. The determination of these biomarkers, however, is analytically challenging since the dynamic concentration range of serum proteins/peptides is extremely wide (more than 10 orders of magnitude). Thus, the reduction in sample complexity prior to proteomic analyses is essential, particularly in analyzing low-abundance protein biomarkers. Here, we demonstrate a novel approach to the proteomic analyses of human serum that uses an originally developed serum protein separation device and a sequentially linked 3-D-LC-MS/MS system. Our hollow-fiber-membrane-based serum pretreatment device can efficiently deplete high-molecular weight proteins and concentrate low-molecular weight proteins/peptides automatically within 1 h. Four independent analyses of healthy human sera pretreated using this unique device, followed by the 3-D-LC-MS/MS successfully produced 12 000-13 000 MS/MS spectra and hit around 1800 proteins (>95% reliability) and 2300 proteins (>80% reliability). We believe that the unique serum pretreatment device and proteomic analysis protocol reported here could be a powerful tool for searching physiological biomarkers by its high throughput (3.7 days per one sample analysis) and high performance of finding low abundant proteins from serum or plasma samples.

LC/MS determination of bisphenol A in river water using a surface-modified molecularly-imprinted polymer as an on-line pretreatment device

A new analytical method for the determination of bisphenol A (BPA) by LC/MS was developed and applied to environmental water samples. Quantitative MS detection of BPA was carried out in the negative mode. In order to preconcentrate the target compound yet prevent serious contamination of the water samples from the experimental environment, we employed column switching HPLC coupled with a pretreatment column of surface-modified molecularly-imprinted polymers. The recovery of BPA from a spiked environmental water sample was 102% and the repeatability of actual determinations of water samples containing 20 ng/L of BPA was 5.4% RSD. By modifying the surfaces of the molecularly-imprinted polymer particles packed in the pretreatment column, interference from the water samples was effectively removed, resulting in a significant increase in sensitivity and more reliable results. This method was successfully applied to the trace determination of BPA in environmental water samples using LC/MS.

Determination of bisphenol A in environmental water at ultra-low level by high-performance liquid chromatography with an effective on-line pretreatment device

We have developed a simple HPLC method for the microanalysis of bisphenol A (BPA), which is often contained in environmental water and is known as an endocrine disrupter. HPLC coupled with electrochemical detection requires a simpler procedure of pretreatment compared to GC–MS. In this study, we analyzed BPA using molecularly imprinted polymer as an on-line pretreatment device. This polymer has molecular recognition sites and provides specific selectivity in extraction process. Due to this effect, the detection limit obtained with this HPLC was 0.36 ng/l. This method applied to environmental water and purified water samples containing 2–70 ng/l of BPA successfully. Furthermore, UV detection was performed in some actual analyses.

Concentrations of hazardous heavy metals in environmental samples collected in Xiamen, China, as determined by vapor generation non-dispersive atomic fluorescence spectrometry.

Non-dispersive atomic fluorescence spectrometry (NDAFS) coupled with vapor generation (VG) sample introduction was applied to the determination of the concentrations of hazardous heavy metals, such as arsenic, cadmium, lead and mercury, in seawater, soils and total airborne particulate matter (PM) collected around the Xiamen area in China. Almost 100% sample introduction efficiency was achieved by using thiourea and ascorbic acid for the pre-reduction of As(V) to As(III), K3Fe(CN)6 and tartaric acid for pre-oxidation of Pb(II) to Pb(IV), and masking the interferences arising from the co-existing transition metals to As, Cd, Hg and Pb during their vapor generation process. Moreover, a novel sample pretreatment device was developed to avoid the loss of mercury, lead, cadmium and arsenic during sample pretreatment. With such methods, the detection limit (DL) of arsenic, cadmium, lead and mercury was down to 0.08, 0.03, 0.05, 0.01 ng mL(-1) (3sigma), respectively. The relative standard deviations (RSD, n = 11) for arsenic, cadmium, lead and mercury at 10 ng mL(-1) were 0.9%, 1.6%, 1.3% and 2.0%, respectively. The concentrations of hazardous heavy metals in the environmental samples collected in Xiamen, China are in the range from 0.02 +/- 0.001 ng mL(-1) in seawater to 15.3 +/- 0.2 microg g(-1) in soils. Besides flame/GF-AAS and ICP-AES/MS, VG-NDAFS should be another choice for the determination of hazardous heavy metals in environmental samples.

Concentration of DNA in a flowing stream for high-sensitivity capillary electrophoresis.

A novel sample pretreatment device is described, and its application to the concentration and purification of crude DNA samples in a flowing stream for subsequent capillary electrophoresis is demonstrated. The device consists of two gap junctions, each covered with a conductive membrane material and built upon a flow channel made of PEEK tubing. Upon the application of an electric field between the junctions, the negatively charged DNA fragments can resist the hydrodynamic flow stream and are trapped between the junctions. DNA fragments dissolved in microliter volumes are captured in a nanoliter-sized band by simply pushing the sample solution through the device. Depending on their electrophoretic mobility, other interfering materials in a crude sample can be removed from the trapped DNA fragments by washing. The selective permeability of the membrane to small ions allows efficient desalting. The concentrated and purified DNA fragments are released by simply turning off or reversing the electric field. Recovery is up to 95%. Performance of the device was evaluated using crude products of fluorescent dye-primer cycle-sequencing reactions. Compared to these crude reaction products, samples purified in the capture device and subsequently collected showed dramatically enhanced signal and resolution when run on a conventional capillary-electrophoresis instrument. Furthermore, the device could be connected in-line to a capillary system for direct injection. The device has great potential for enabling lab-on-a-chip systems to be used with real-world samples.

Identification of odors using a sensor array with kinetic working temperature and Fourier spectrum analysis

A method for the identification of odors using a dynamically driven sensor array has been developed, in which transient responses of the sensor array were used to recognize target odors. Fourier transformation was used to transform the transient response curves of the sensor array into Fourier spectra, and patterns composed of some of the magnitudes in the spectra were used in the pattern recognition to identify the odors. Identification of odors was performed using this method with three kinds of 10% ethanol solution of tea extract and three kinds of Japanese soy sauce. In consequence, the sample odors could be correctly recognized without any pretreatment device for separation of minor components from the main component.

Anaerobic pretreatment of hazardous waste leachates in publicly owned treatment works

Feasibility studies have been completed for an anaerobic pretreatment system designed to treat hazardous waste leachates in publicly owned treatment works. The system was designed to mitigate many of the problems associated with conventional aerobic treatment of these wastes and other types of dilute waterborne hazardous wastes. In this new approach, a contact/sorption stage consisting of an expanded bed of granular activated carbon (GAC) with an attached anaerobic biomass was used as a pretreatment device after primary clarification before the aerobic treatment portion of the plant. This sorption stage was intended to reduce pass-through of toxics, retaining them for subsequent treatment in a separate anaerobic stabilization reactor. The organic-rich GAC/biomass bed from the sorption stage was exchanged with stabilized GAC biomass from the anaerobic stabilization stage, conserving the GAC in the system.Two 87-L/d bench-scale systems were operated for 332 days, one treating unspiked primary effluent and one treating primary effluent spiked with 5% landfill leachate and 14 hazardous organic compounds. In the spiked system, removals in the sorption stage were the highest for the aromatic compounds. Five of the six aromatics added were removed at over 95% and the sixth, phenol, had an 85% removal. Removals of chlorinated aliphatic compounds ranged from 52% for methylene chloride to 95% for trichloroethylene. Removals of phthalate compounds were approximately 60%. Removals of ketones ranged from 24% for acetone to 93% for methyl isobutyl ketone. Chemical oxygen demand removals remained at 40% to 50% throughout the year-long study in both systems.

In-Line Pretreatment Method for Flow Injection Analysis of Total Phosphorus and Nitrogen Impurities in Hydrogen Peroxide Solution

Controlling various impurities below their tolerable limits is frequently required for high purity chemicals to be used in the semiconductor industry. We have developed an in-line pretreatment device which can be coupled with the flow injection analysis (FIA) system developed for simultaneous determination of total phosphorus (TP) and total nitrogen (TN) in water

Experience and results on the operation of the common pretreatment at DROP

Within the scope of a joint research programme between KISR /WRDC Kuwait and the GKSS Research Center FRG, a RO plant of a total capacity of 3000 m 3/d is being operated in Kuwait. The plant comprises three lines, equipped with different types of modules (spiral wound, hollow fine fibre, plate and frame). The raw water for all 3 units is processed in one pre-treatment device. If necessary, additional pre-treatment stages are installed for the individual RO lines. The plant described in the following operates in accordance with the so-called Wahnbach Process (1). Pre-treatment is effected by flocculation and filtration via multi-layer filters. For more than two years now this plant is being operated with high availability. The pre-treated water can be used for plate and frame as well as spiral wound moduls. For the line equipped with hollow fine fibres, an additional pre-treatment stage is essential.