A microfluidic device for continuous, real time blood plasma separation

A microfluidic device for continuous, real time blood plasma separation is introduced. The principle of the blood plasma separation from blood cells is supported by the Zweifach-Fung effect and was experimentally demonstrated using simple microchannels. The blood plasma separation device is composed of a blood inlet, a bifurcating region which leads to a purified plasma outlet, and a concentrated blood cell outlet. It was designed to separate blood plasma from an initial blood sample of up to 45% inlet hematocrit (volume percentage of cells). The microfluidic network was designed using an analogous electrical circuit, as well as analytical and numerical studies. The functionality of this device was demonstrated using defibrinated sheep blood. During 30 minutes of continuous blood infusion through the device, all the erythrocytes (red blood cells) traveled through the device toward the concentrated blood outlet while only the plasma was separated at the bifurcating regions and flowed towards the plasma outlet. The device has been operated continuously without any clogging or hemolysis of cells. The experimentally determined plasma selectivity with respect to blood hematocrit level was almost 100% regardless of the inlet hematocrit. The total plasma separation volume percent varied from 15% to 25% with increasing inlet hematocrit. Due to the device's simple structure and control mechanism, this microdevice is expected to be used for highly efficient continuous, real time cell-free blood plasma separation from blood samples for use in lab on a chip applications.     

Ultrahigh throughput beehive-like device for blood plasma separation

We report here a low-cost, rapid-prototyping, and beehive-like multilayer polymer microfluidic device for ultrahigh-throughput blood plasma separation. To understand the device physics and optimize the device structure, the effect of cross-sectional dimension and operational parameter on particle focusing behavior was explored using a single spiral microchannel device. Then, the blood plasma separation performance of the determined channel structure was validated using the blood samples with different hematocrits (HCTs). It was found that a high separation efficiency of 99% could be achieved using the blood sample with an HCT of 0.5% at a high throughput of 1 mL/min. Finally, a multilayer microfluidic device with a novel beehive-like multiplexing channel arrangement was developed for ultrahigh-throughput blood plasma separation. The prototype device could be fabricated within ∼1 hour utilizing the laser cutting and thermal lamination methods. The total processing throughput could reach up to 72 mL/min for 0.5% HCT sample with a plasma separation ratio close to 90%. Our device may hold potentials for the ultrahigh-throughput separation of blood plasma from large volume blood samples for downstream disease diagnosis.     

A novel non-invasive electrochemical biosensing device for in situ determination of the alcohol content in blood by monitoring ethanol in sweat

A non-invasive, passive and simple to use skin surface based sensing device for determining the blood's ethanol content (BAC) by monitoring transdermal alcohol concentration (TAC) is designed and developed. The proposed prototype is based on bienzyme amperometric composite biosensors that are sensitive to the variation of ethanol concentration. The prototype correlates, through previous calibration set-up, the amperometric signal generated from ethanol in sweat with its content in blood in a short period of time. The characteristics of this sensor device permit determination of the ethanol concentration in isolated and in continuous form, giving information of the BAC of a subject either in a given moment or its evolution during long periods of time (8 h). Moreover, as the measurements are performed in a biological fluid, the evaluated individual is not able to alter the result of the analysis. The maximum limit of ethanol in blood allowed by legislation is included within the linear range of the device (0.0005–0.6 g L⁻¹). Moreover, the device shows higher sensitivity than the breathalyzers marketed at the moment, allowing the monitoring of the ethanol content in blood to be obtained just 5 min after ingestion of the alcoholic drink. The comparison of the obtained results using the proposed device in the analysis of 40 volunteers with those provided by the gas chromatographic reference method for determination of BAC pointed out that there were no significant differences between both methods.     

一种富集海水中有机氯和菊酯类农药的船载式正压固相萃取装置

研制了一种正压驱动的新型固相萃取(SPE)装置以替代真空泵负压驱动SPE装置用于富集海水中的有机氯和菊酯类农药。与水样接触的采样瓶和管路均采用不含氯的塑料材质。整个装置的连接部分用螺母螺栓紧固,以保证密封性和牢固性。水样瓶内部的压力(0.1~0.3 MPa)由单片机和压力传感器控制的隔膜充气泵(12 V电池供电)提供,水样过柱的流速在4.0~6.0 mL/min之间。SPE柱预淋洗后储存4周内有效,采样后储存6周内回收率大于80%。方法的线性关系良好,相关系数均大于0.9,方法的定量限为0.8~6.0 ng/L,3个不同添加水平(n=3)的平均回收率为86.1%~95.5%,相对标准偏差小于10%。海水实际样品中均检出六六六(BHC)和滴滴涕(DDT)。该装置在富集海水中有机氯和菊酯类农药方面有较好的应用。     

Electro-kinetically driven route for highly sensitive blood pathology on a paper-based device

Enhancing the sensitivity of colorimetric detection in paper-devices is a quintessential step in achieving frugal diagnosis. Here, we demonstrate an effective way of improving the detection sensitivity of paper-based devices, as mediated by electro-kinetic mechanisms. By directly employing blood plasma, we investigate the electro-kinetic clustering of glucose, a neutral molecule in paper devices. Under the influence of uniform electric field, dispersed glucose gets accumulated in the paper strips. Due to the combination of EOF and electrophoretic migration, we achieve twofold increase in the colour intensity for both normal and diabetic samples. This approach is robust and possesses better sensitivity than conventional colorimetric assays and can be easily extended to other body fluid based diagnosis. These results may turn out to be of profound importance in improving the quality of pathological diagnosis in low-cost paper-based point-of-care devices deployed in resource-limited settings.     

A passive microfluidic device for continuous microparticle enrichment

A passive microfluidic device is reported for continuous microparticle enrichment. The microparticle is enriched based on the inertial effect in a microchannel with contracting‐expanding structures on one side where microparticles/cells are subjected to the inertial lift force and the momentum‐change‐induced inertial force induced by highly curved streamlines. Under the combined effect of the two forces, yeast cells and microparticles of different sizes were continuously focused in the present device over a range of Reynolds numbers from 16.7 to 125. ～68% of the particle‐free liquid was separated from the sample at Re = 66.7, and ～18 μL particle‐free liquid was fast obtained within 10 s. Results also showed that the geometry of the contracting‐expanding structure significantly influenced the lateral migration of the particle. Structures with a large angle induced strong inertial effect and weak disturbance effect of vortex on the particle, both of which enhanced the microparticle enrichment in microchannel. With simple structure, small footprint (18 × 0.35 mm), easy operation and cell‐friendly property, the present device has great potential in biomedical applications, such as the enrichment of cells and the fast extraction of plasma from blood for disease diagnose and therapy.     

Amperometric biosensor for rapid measurement of 3-hydroxybutyrate in undiluted whole blood and plasma

A simple, rapid (< 30 s) electrochemical method for the determination of 3-hydroxybutyrate in whole blood or plasma is described, which uses NAD⁺-dependent d-3-hydroxybutyrate dehydrogenase immobilized at novel platinized carbon electrodes. The steady-state oxidation current produced by enzymatically generated NADH is measured at + 150 mV vs. Ag/AgCl. Enzyme electrodes produced by direct adsorption were stable for at least 3 months. Undiluted whole blood measurement with the sensor was compared with routine spectrophotometric analysis of plasma and perchloric acid extracts of whole blood.     

Non‐oxidized graphene/elastomer composite films for wearable strain and pressure sensors with ultra‐high flexibility and sensitivity

It remains challenging to prepare wearable strain and pressure sensors with excellent mechanical properties, ultra‐high flexibility and sensitivity. Electrically conductive graphene platelets (GnPs) with high structural integrity are used in making a composite film fabricated using robust fabrication techniques. The gauge factor for the strain is up to 100 at 0%‐5% strain and 50 at 5%‐30% strain, and the sensitivity to pressure is 2.7×10^‐2 kPa^‐1 between 0 and 10 kPa and 1.5×10^‐4 kPa^‐1 between 300 and 1000 kPa. In addition, the flexible sensor demonstrates good repeatability and durability after 1000 cycles of tensile and compression tests. The flexible sensor has fast response ability and a wide operating temperature range, suggesting the excellent response to temperature. The flexible sensor is applied in monitoring several human motions as a wearable device with high accuracy. The ability to detect strain, pressure and temperature of the flexible sensor extends its applications to multifunctional wearable devices.     

A new device for checking surface contamination based upon electrical measurement

Surface treatments, such as plating, painting, marking or assembling with adhesives, require reliable surface cleanliness. Industrial workshops cannot use sophisticated techniques, and there is a need for fast and reliable tests. Very simple drop or marker tests exist, but they provide only go — no go information. Measurements of electrical surface potential decay have been found to be convenient, and a commercial device for metal surfaces is now available, based upon this principle. Positive electrical charges are deposited upon the metal through corona discharge, and the resulting surface potential is measured by an electrostatic probe; its decay is followed over 5–10s. Usually, the relationship between the logarithm of the potential and the decay time is linear; a microcomputer calculates the two parameters of this law, which are related to the nature and thickness of the contaminating layer. Flatness of the surface is not required, making it possible to control parts with various geometries. It is easy to compare the contamination of a surface with a standard, and to decide whether the surface can be considered sufficiently clean. The device is rather small, inexpensive and very simple to operate; it is designed for quality control in industry. Developments for plastic parts are under progress, and valuable results have already been obtained, e.g. for ageing of epoxy parts.     

A novel fiber optical device for ultraviolet disinfection of water

Since there are several problems in traditional UV disinfection techniques, a highly efficient, reliable and economical method, using quartz optical fibers to deliver UV light is proposed. The principle of the experimental setup is that ultraviolet rays are gathered by a reflector and converge on a light point, the diameter of approximately 5mm. In this way UV light can be transferred into water to kill the bacteria in the water. This paper presents preliminary results on water disinfection using this new UV disinfection setup. Its suitability for application could be shown in experiments with E. coli (ATCC8099) as test microorganisms. We have optimized the distribution of the optical fibers in the water in bench-scale study. This result can provide guidance for pilot-scale and field-scale study of this new technique. The results show that the new technique had a good performance under different conditions as follows: (a) turbidity level=10.2 NTU, (b) ferric ion concentration=0.3 mg/L, and (c) humic acid concentration=5 mg/L. The new technique provides a promising approach to disinfection treatment of drinking water.     

A novel technique for on-capillary preconcentration of anionic compounds applied to the trace analysis of rapamycin in human blood by capillary electrophoresis

A capillary electrophoretic (CE) method with UV detection at 278 nm has been developed for analysis of the immunosuppressant rapamycin (sirolimus) in human blood at low microg.L(-1) levels. Separation has been achieved in an acidic carrier electrolyte containing sodium dodecyl sulfate and 20% v/v methanol. For sample cleanup and preconcentration, both an off-line solid-phase extraction step using a silica-based reversed-phase material and a newly developed on-capillary focusing technique have been employed. The subsequent treatment of rapamycin under alkaline conditions leads to a cleavage of the lacton bond of the molecule, generating a negatively charged carboxylic group which allows electrokinetic injection into the CE instrument. During the injection process, the negatively charged analyte migrates into an acidic carrier electrolyte, so that it becomes neutral due to protonation and is focused at the capillary inlet. Injection times of 300 s at -7.5 kV could be applied without band-broadening. Results for real samples indicated that the method is fully suited for routine applications and may be an attractive alternative to established liquid chromatographic techniques.     

A novel approach simulating pressure on square ice clusters

The recent experimental discovery of square ice under pressure has motivated the present study of some purely planar cluster of N water molecules by quantum chemical methods. As a starting point, four H₂O molecules in a square bonded by H-bonds were examined. In order to assess how such a low-lying planar isomer might tend to ‘square ice’ for an infinite sheet, we follow with N = 16, 36 and 64 H₂O clusters. Subsequently, the effect of pressure, simulated by the application of a quadrupolar field, on the structures of the different flakes as well as on the vibrational frequencies of the four-molecule cluster is studied.     

离子液体1-丙基-3-甲基咪唑醋酸盐[C_3mim][OAc]蒸气压和蒸发焓的测定及极性预测

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Vapor pressure measurement for water,methanol, ethanol,and their binary mixtures in the presence of an ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate

Vapor pressure data were measured for water, methanol and ethanol as well as their binary mixtures with an ionic liquid (IL) 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM][DMP]) at varying temperature and IL-content ranging from mass fraction of 0.10–0.70 by a quasi-static method. The vapor pressure data for the IL-containing binary systems were correlated using NRTL equation with average absolute relative deviation (ARD) within 0.0076, and the binary NRTL parameters was used for predicting the vapor pressure of the IL-containing ternary systems with reasonable accuracy. In addition, the infinite activity coefficients of solvents in [EMIM][DMP] and isobaric vapor–liquid equilibrium for IL-containing ternary systems at 101.325 kPa and mass fraction of IL being 0.5 were predicted with the regressed NRTL parameters. The results indicate that ionic liquid [EMIM][DMP] can depress the volatility of the solvents of water, methanol and ethanol but to a varying degree, leading to the variation of relative volatility of a solvent and even removal of azeotrope for water–ethanol mixture.     

A novel photo-initiated approach for preparing aluminum diethylphosphinate under atmospheric pressure

A novel preparation of aluminum diethylphosphinate（AlPi） was carried out with free-radical addition reaction by means of UV-irradiation under atmospheric pressure.A solution of sodium hypophosphite was treated with ethylene and irradiated with ultraviolet light in the presence of an amount of photoinitiator effective to initiate the free-radical reaction between the hypophosphite anion and the double bond of the ethylene molecule.The ethylene was micro-bubbled into the reaction mixture with the addition of the photoinitiator,and the gas-liquid contact surface and the photoinitiator concentration in the gas-liquid interface were increased largely.The yield of the final product could be improved to about 96%.The contents of P,Al in samples were detected by ICP,and the molecular structure of the samples was confirmed by ³¹P NMR,¹H NMR and FTIR spectroscopic analysis.Thermal stability of the final products was investigated in detail by TG-DTA.     

Cyclization of aromatic aldehydes and phenylenediamines under reduced pressure: A convenient,environmentally friendly,and simple procedure for benzimidazole precursors

The condensation of phenylenediamines with aromatic aldehydes in the presence of catalysts to obtain benzimidazoles under harsh condition is achieved by various reported conditions. The present work demonstrates a convenient, environmentally friendly, and simple procedure to obtain benzimidazoles through the cyclization between phenylenediamines and aromatic aldehydes under reduced pressure. By simply adding aromatic aldehydes to diaminobenzene derivatives and allowing the stoichiometric reaction at room temperature under reduced pressure at 66.6?Pa, the dehydrogenation leads to benzimidazoles with the yield as high as 80–90%. In addition, the purging of H₂ gas to benzimidazoles results in the hydrogenation of imidazole to obtain the intermediate benzimidazolidine form. This confirms how the cyclization relies on the reduced pressure. This synthesis pathway not only gives the aromatic aldehydes with high yield under the mild condition but also the selection of benzaldehydes with reactive functional groups leads to the precursors for other chemical modifications and polymerizations.     

A novel monolithic silicon sensor for measuring acceleration,pressure and temperature on a shock absorber

A fabricated micro-mechanical sensor to assess the condition of automotive shock absorbers is presented. The monolithic sensor, measures the oil temperature, acceleration and internal pressure of the shock absorber. A dual mass accelerometer with optimized beam geometry is used for acceleration readout. In addition, a 23.1 μm thickness square membrane and two buried resistors are used for pressure and temperature sensing respectively. The proposed miniaturized sensor can be effectively integrated with standard single- and dual-tube shock absorbers. The data acquired during normal vehicle operation can be continuously used to monitor the condition of the shock absorbers, allowing shock absorbers to be replaced before their degradation significantly reduce the comfort, performance and safety of the vehicle.     

Rapid quick,easy, cheap,effective, rugged,and safe extraction with novel phospholipid cleanup: A streamlined ultra high performance liquid chromatography with ultraviolet detection approach for screening polycyclic aromatic hydrocarbons in avian blood cells and plasma

A streamlined method has been developed for the isolation and analysis of polycyclic aromatic hydrocarbons in avian blood cells and plasma utilizing quick, easy, cheap, effective, rugged, and safe extraction in combination with novel phospholipid cleanup technology. A variety of traditional extraction and cleanup techniques have been employed in the preparation and analysis of polycyclic aromatic hydrocarbonsin a variety of matrices; liquid–liquid partitioning, solid‐phase extractions, gel permeation chromatography, and column chromatography are all effective techniques, however they are laborious and time consuming processes that require large amounts of solvent. Using quick, easy, cheap, effective, rugged, and safe extraction coupled with phospholipid cleanup, samples can be quickly screened while maintaining high throughput and sensitivity. With a liquid chromatography approach, analysis times may be kept short at 16 min while maintaining high analyte recovery. Recoveries in quality control samples ranged from 70 to 109%, with average surrogate recoveries of 80.6 ± 1.10%. The result of using a quick, easy, cheap, effective, rugged, and safe extraction approach in conjunction with phospholipid cleanup is a methodology that significantly reduces sample preparation time and solvent use while maintaining high sensitivity and reproducibility.     

Development and validation of a novel rheological test device and measurement system for determining the influence of humidity on viscosity

Although a strong impact of humidity on polymers and the formation of their molecular network is known, the complex interactions between humidity, temperature, diffusion, reaction kinetics, rheological behaviour and mechanical properties are not fully understood yet. Most current approaches solely analyse the relationships between environmental conditions in a solidified or crosslinked state and the mechanical properties. In contrast, this work focusses on measuring changes in rheological properties depending on relative humidity in the liquid state. A custom designed novel measuring geometry is introduced and validated. It enables for the first time to rheometrically investigate the influence of relative humidity on reactive systems during their cross-linking process. Our results significantly depict the influence of humidity on the cross-linking process and the gel time. The potential of the introduced measuring geometry for improving reactive systems, adapting these precisely to environmental boundary conditions or assuring product performance is hereby demonstrated. This is especially important for industrial manufacturing processes running at different production sites around the world in different climatic zones or repair processes being performed outdoor, e.g. for wind energy plants.