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Applications of microsystems (microreactors) in continuous-flow chemistry have expanded rapidly over the past two decades, with numerous reports of higher conversions and yields compared to conventional batch benchtop equipment. Synthesis applications are enhanced by chemical information gained from integrating microreactor components with sensors, actuators, and automated fluid handling. Moreover, miniaturized systems allow experiments on well-defined samples at conditions not easily accessed by conventional means, such as reactions at high pressure and temperatures. The wealth of synthesis information that could potentially be acquired through use of microreactors integrated with physical sensors and analytical chemistry techniques for online reaction monitoring has not yet been well explored. The increased efficiency resulting from use of continuous-flow microreactor platforms to automate reaction screening and optimization encourages a shift from current batchwise chemical reaction development to this new approach. We review advances in this new area and provide application examples of online monitoring and automation.

Miniaturizing experimental sample volumes to the nanoliter volume range is one of the most economical ways to perform mid- and high-throughput compound screening experiments. Existing automation platforms for nanoliter fluid handling can be bulky, expensive, and require periodic calibration to provide consistent liquid dispensing. In addition, even with frequent calibration, significant instrument-to-instrument variation in low-volume dispensing can occur between different instrument platforms. Many of these issues can be addressed by the use of PocketTips. PocketTips are tips with a defined internal pocket designed to hold specific nanoliter volumes of compound dissolved in dimethylsulfoxide. Although the overall liquid-handling process with PocketTips uses the aspirate/dispense features of the specific liquid-handling device being used, the dispensed nanoliter volume is solely based on the dimensions of the pocket of the PocketTip and thus, the liquid-handling device itself need not have nanoliter dispensing capabilities. In this report, we demonstrate the performance of PocketTips on different automation platforms. In addition, we used a cell-based β-lactamase reporter assay system to demonstrate that compound delivery by PocketTips compares favorably with a standard compound addition technique.

The thrust of this R&D effort was to develop technology that serves the SOFC industry and help developers in this industry to succeed. In particular this project focused on fluid handling equipment that supported the SOFC stack. Two devices were developed: the Hot Anode Recycle Blower (HARB) blower which will serve hot anode gas requirements in FutureGen demonstration units, and the small multi stage (SMS) blower which will serve warm anode and cathode gas requirements for SOFC and other fuel cell industries.

Although advanced fluid handling using elastomeric valves is useful for a variety of lab-on-a-chip procedures, their operation has traditionally relied on external laboratory infrastructure (such as gas tanks, computers, and ground electricity). This dependence has held back the use of elastomeric microvalves for point-of-care settings. Here, we demonstrate that microfabricated microvalves, via liquid-filled control channels, can be actuated using only a handheld instrument powered by a 9 V battery. This setup can achieve on–off fluid control with fast response times, coordinated switching of multiple valves, and operation of a biological assay. In the future, this technique may enable the widely used elastomeric microvalves (made by multilayer soft lithography) to be increasingly adopted for portable sensors and lab-on-a-chip systems.

Wounds naturally produce exudate containing nutrients, blood cells, enzymes, cytokines and growth factors, which are all essential to the healing process. When this balance is altered by local or systemic conditions then exudate can become problematic. Wound healing is delayed, quality of life is detrimentally affected and nursing staff are faced with time-consuming dressings. The wound product market has always contained absorbent dressings, yet there is a need for further absorbent dressings to be made available to us. This has seen the introduction of super-absorbent dressings onto the market. One of these dressings, Eclypse®, is discussed in this article. Eclypse uses highly absorbent crystal technology to increase its fluid handling capacity. The functionality of this product and the benefit for patients derived from its use are described in this article.

Wound malodour is rapidly becoming a critical issue, particularly with patients suffering with chronic illness that often result in wounds such as; venous leg ulcers, diabetic ulcers, pressure ulcers and fungating (malignant cancerous) lesions. The malodour is usually just part of the whole chronic situation but it can affect the patient in numerous social and psychological ways. There are specific wound dressings on ‘Drug Tariff to treat malodour. These contain a layer of activated charcoal which facilitates the adsorbing of wound malodour. Although activated charcoal is efficient in the adsorption of volatile odorous molecules, there are some issues with its use in wound dressings and these are: a) Activated charcoal cloth is black in colour; b) it is relatively weak in nature and can be easily ruptured and presents a risk of the broken fragments of carbon fibre contaminating the wound, if exposed; c) the efficiency of the ability to adsorb odorous volatile molecules is compromised if saturated with the molecular rich wound exudate; and d) activated charcoal cloth is relatively expensive to produce and this is often reflected in the cost of the final products. In order to address the above limitations, a research programme is in progress at the University of Bolton one of the objectives of this research is to investigate and develop a viable test method for evaluating the efficiency of odour adsorption, whilst researching and developing novel odour/volatile adsorbent materials, to possibly replace the use of activated charcoal. To date there appears to be a dearth of quantitative comparable data on these specific wound dressings particularly on their odour adsorption efficiency; this may be due to the limitation of realistic test methods of evaluating this characteristic. Further research work has been carried out on a novel test method for odour adsorption that has combined the efficiency of odour adsorption together with the assessment of fluid handling capabilities. Although there are still some criticisms with this method it appears to be the nearest, to date that simulates some of the physical conditions that the product would experience in use. A selection of currently available activated charcoal wound dressing products have been tested, evaluated and quantitative comparable data collected. Some natural polymeric antimicrobial agents have also been tested and evaluated for their potential odour adsorption efficiency. These results will enable us to develop, engineer and characterise a range of novel odour adsorbent materials by using innovative fibres/polymers, fabric structures and composites incorporating adsorptive and antimicrobial properties.

Purpose of review Perioperative fluid management influences patient outcome. Vascular surgery unites various surgical procedures, mainly with a high impact on patients who often have relevant preexisting illnesses. There are only scarce data on this specialty, forcing the clinician to extrapolate existing data when planning perioperative fluid management. This review aims to summarize the underlying facts. Recent findings Perioperative insensible perspiration does not exceed 1 ml/kg per hour. A third space shift does not exist; therefore, its primary substitution is erroneous. Rather, a crystalloid fluid excess causes a tremendous shift towards the interstitial space. Colloidal volume effects are context sensitive, that is, only their use as a substitute when blood or plasma loss occurs leads to maintenance within the circulatory space, Colloidal hypervolaemia and surgical trauma both have the potential to deteriorate the vascular barrier, leading to plasma loss into the interstitial space. Current perioperative fluid therapy should aim to maintain normovolaemia of the individual body fluid compartments as far as possible. This might be achieved by combining a protocol-based replacement of extracellular losses (urinary output plus insensible perspiration) with isotonic balanced crystalloids and blood volume optimization using isooncotic colloids. Summary The basis of fluid therapy in vascular surgery is a careful differential indication of the respective classes of preparations. A goal-directed approach might help to avoid hypovolaemia

In this issue of Clinical Chemistry , Gambino et al. (1) describe careful studies of a blood-collection container that stabilizes the concentration of glucose in blood samples. At a time of an increasing disease burden attributable to diabetes and the use of lower glucose concentrations than in the past for the diagnosis of diabetes, this study and its findings are especially important. Measurements of glucose are used worldwide to diagnose diabetes and to identify patients at risk of developing diabetes [e.g., (2)(3)]. For both diagnosis and risk assessment, fixed cutpoints of plasma glucose concentrations are used to classify patients and to make decisions regarding management. For this reason, all steps in the analytical process require careful attention. Clinical chemists in hospital laboratories and diagnostic companies have made great strides in improving the measurement of glucose. With the use of enzymatic methods and sophisticated analyzers with stable optics, electronics, fluid handling, and other components, central clinical laboratories routinely achieve an astoundingly low within-laboratory imprecision (CV) of 1%–2%. [Glucose meters do not fare so well and are not recommended for diagnosis of diabetes (4).] By contrast, the preanalytical issues surrounding glucose measurements have not been solved. The loss of glucose in blood samples has been studied for many years (5). Glucose is lost through glycolysis at a rate of 5%–7%/h at concentrations near the reference interval. In absolute terms, a loss in glucose of about 0.67 mmol/L (12 mg/dL) occurs at a concentration of 5.55 mmol/L (100 mg/dL) after 2 h at room temperature (6). Higher rates of loss occur commonly, such as with increased ambient temperature and in samples with high white blood cell counts. In 1923, Major introduced potassium fluoride as a potent inhibitor of glycolysis (7), and fluoride, usually as NaF, has been used for decades to …

Wound dressings are the most rapidly developing products of medical textiles and have a great significance for a successful wound treatment. Nowadays, varieties and properties of wound dressings have increased with modern understanding and usage of materials and technologies. Providing a moist environment is the basis of these developments. This balanced environment facilitates cellular growth and collagen proliferation within acellular matrix. Hence, the modern wound dressings are based on the concept of creating optimum conditions to allow epithelial cells so as to move unimpeded for the treatment and healing of wounds. In this respect, the ideal wound dressing should also provide effective oxygen circulation to aid regenerating cells for rapid healing with minimum inconvenience to the patient. The variety of wound types and wounded patient characters has resulted in a wide range of wound dressings. Taking wound dressings into considerations, this chapter offers a review of the test methods of emerging modern wound dressings for achieving improved wound healing.

Textile based sensors which can be used to measure the chemical composition of bodily fluids represents a major advancement in the area of wearable technology. BIOTEX is an EU funded project aiming to develop such sensors with a particular interest in monitoring perspiration. A textile based fluid handling system has been developed for sample collection and transport. Sodium, conductivity and pH sensors have also been developed. This paper details the integration and testing of these sensors. Results show that the developed system can collect and analyze sweat in real time during exercise and transmit this data wirelessly to a remote receiver.

This paper details the development of a textile based fluid handling system with integrated wireless biochemical sensors. Such research represents a new advancement in the area of wearable technologies. The system contains pH, sodium and conductivity sensors. It has been demonstrated during on-body trials that the pH sensor has close agreement with measurements obtained using a reference pH probe. Initial investigations into the sodium and conductivity sensors have shown their suitability for integration into the wearable system. It is thought that applications exist in personal health and sports performance and training.

Digital microfluidics has become a popular tool for biochemical and biomedical applications. However, its current format is restricted to actuation of droplets on a single plane. Here, we introduce a new method for fluid handling on flexible devices, which we have termed all-terrain droplet actuation (ATDA). We show that ATDA can be used to manipulate droplets across a wide range of geometries, including inclined, declined, vertical, twisted, and upside-down architectures. These new geometries enable flexible, straightforward integration of distinct physicochemical environments on monolithic devices. To illustrate this capacity, we developed temperature- and oxygen-sensitive colorimetric sensors, as well as an automated method for selective enrichment of DNA from a heterogeneous mixture. We anticipate that ATDA will be a useful new tool in the growing trend toward laboratory miniaturization.

Understanding the costs of implementing a new or revised space launch system is a key to understanding its business potential, analyzing its business case and funding its development. The design, construction and startup of a launch complex (including launch mount, flame deflector, component and fluid handling equipment, support equipment and facilities) represents a significant portion of the non-recurring costs for a new launch system. By understanding the factors which drive these costs, informed decisions can be made early in a program to give the business case the best chance of economic success. The authors have designed several NASA, military, commercial and private launch complexes. Data from these designs has been used to identify the major factors which, on a broad scale, drive their non-recurring costs. Both vehicle specific and location specific factors play major roles in establishing costs.

To sequentially handle fluids is of great significance in quantitative biology, analytical chemistry, and bioassays. However, the technological options are limited when building such microfluidic sequential processing systems, and one of the encountered challenges is the need for reliable, efficient, and mass-production available microfluidic pumping methods. Herein, we present a bubble-free and pumping-control unified liquid handling method that is compatible with large-scale manufacture, termed multilayer microfluidic sample isolated pumping (mμSIP). The core part of the mμSIP is the selective permeable membrane that isolates the fluidic layer from the pneumatic layer. The air diffusion from the fluidic channel network into the degassing pneumatic channel network leads to fluidic channel pressure variation, which further results in consistent bubble-free liquid pumping into the channels and the dead-end chambers. We characterize the mμSIP by comparing the fluidic actuation processes with different parameters and a flow rate range of 0.013 μl/s to 0.097 μl/s is observed in the experiments. As the proof of concept, we demonstrate an automatic sequential fluid handling system aiming at digital assays and immunoassays, which further proves the unified pumping-control and suggests that the mμSIP is suitable for functional microfluidic assays with minimal operations. We believe that the mμSIP technology and demonstrated automatic sequential fluid handling system would enrich the microfluidic toolbox and benefit further inventions.

Quite often, important cellular events occur in environments that are either not amenable to implanted sensors or other types of molecular probes. In such cases, a viable alternative to taking the sensor or probe to the biological sample of interest is to bring the sample of interest out of its natural environment to one that is more conducive to the measurement scheme. The disadvantage of the latter approach is that the sample may not behave in the same manner in vitro as it does in vivo, or that the agonists and other stimuli to which the sample is subjected to in vivo are no longer present. In this Tutorial Review, the authors attempt to provide some guidance, based on their own experiences and those of other scientists, to performing cellular measurements in a quantitative manner under in vitro conditions. Due to the expansive literature on analyses involving cells, the authors have limited this Tutorial Review to those methods involving microfluidic technologies, both in microbore tubing and in microfabricated channels. Initial reports of analyses involving cells in microbore tubing were first reported nearly two decades ago, while those in microfabricated fluidic devices appeared over a decade ago. However, more recently, the complexity of cell analyses using fabricated microfluidic devices (as opposed to microbore tubing) has increased due in part to the improvements in fabrication technologies, fluid handling and delivery capabilities, advances in coatings of the channels within the microfluidic device, and integrated detection schemes. Examples of cellular analyses in microbore tubing and in fabricated microfluidic devices will be given, as well as associated advantages and challenges. Finally, the authors' thoughts on cellular analyses are presented here using the classical steps in an analysis as a guide.

Background: Applications of fluorescence-activated cell sorting (FACS) are ideally performed under aseptic conditions so that isolated cells can be successfully cultured, transplanted, or processed for the isolation of protein and nucleic acids. However, modern “off-the shelf” flow cytometers are suboptimally designed for these purposes because nonsterile instrument hardware components directly contact sample-harboring fluids, compromising their sterility. Methods: We have described the design and modular modification of a cytometer with a sterile and disposable FACS fluid handling system that meets requirements of high-speed FACS and good manufacturing practice. This system was tested for functionality and its ability to maintain a clean and sterile fluid environment. Results: Our data have shown that this new fluidic subsystem completely replicated the intended function of the manufacturer's standard fluid handling system, and isolates the fluid from contaminants such as bacteria and fungus, endotoxins, mycoplasma, and helicobacter. Conclusions: FACS has emerged as a powerful tool used to study and manipulate stem cells. However, if stem cell discoveries are to be fully utilized in clinical transplant medicine, aseptic instrument configurations must be developed. For this purpose, we have designed a disposable sterile fluid handling system. © 2006 International Society for Analytical Cytology

Our studies of second generation immersion fluid candidates are moving beyond the discovery phase, and into addressing issues for their commercial application. Thus, we continue work to examine and fundamentally understand fluid transparency and refractive index, to fully optimize these properties. At the same time, we are now examining other process concerns, including index variation with temperature, new imaging performance studies, fluid handling considerations, and fluid property maintenance with active recycle during lithographic exposure. The systems and procedures we have developed in these areas continue to show our fluids' promise for sub-45nm immersion lithography applications.

We have succeeded in the creation of a new fluid handling system in a microspace using cultured cardiomyocytes as a component of a micropump. In order to communicate the force generated by cardiomyocytes to fluid, a thin diaphragm and a push bar structure made of PDMS were assembled onto a microchannel and cardiomyocytes sheet was attached on them. Estimated flow rate of this micropump was 52 nL/min. The applied pressure on the diaphragm generated by cardiomyocytes was 2Pa. This is the first demonstration of microheart pump using cardiomyocytes sheet only by chemical energy without electrical power supply.

The Genomation Laboratory at the University of Washington is developing an automated fluid handling system called "Acapella" to prepare microliter reactions for genome analysis. The system prepares 5,000 samples in 8 hours for general-purpose chemistry analysis including DNA sequencing reaction preparation.

The fluid handling and microbiological properties of a non-antimicrobial Hydrofiber ® (NAH) wound dressing have been compared with those of a silver salt-containing Hydrofiber ® (SCH). Fluorescent dyes ( Bac Light™, Live/Dead™ Kit) were added to fresh cultures of two wound pathogens ( Pseudomonas aeruginosa and Staphylococcus aureus ), and used to visualise their viability. Live bacteria stained green and dead/dying bacteria turned red. When inoculated into samples of the NAH and SCH dressings, the viability of the bacteria could be effectively monitored over time using a rapid form of confocal laser scanning microscopy (RCLSM—Leica ® UK). When the NAH dressing was hydrated with stained bacterial culture, its fibres swelled quickly, reducing interstitial spaces between the fibres, resulting in the formation of a cohesive gel. Bacteria became immobilised in the gel, forming characteristic clumps, but remained largely green (viable) for more than 20 h with no apparent increase in numbers. The SCH initially behaved in a similar manner, however, using 3-D data from RCLSM time-lapse sequences P. aeruginosa was observed to turn progressively red (i.e. died) within 1.5–3 h and S. aureus similarly turned red within 5–7 h of contact with the SCH dressing. The ability of both Hydrofiber ® dressings to sequester and immobilise potentially pathogenic wound micro-organisms has been demonstrated. Additionally the SCH dressing was shown to kill immobilised bacteria, as a consequence of the ionic silver bactericide. These properties of the Hydrofiber ® dressings may contribute to providing an environment that is supportive to wound healing.

El objetivo del presente trabajo fue medir las caídas de presión para obtener los coeficientes de fricción de fluidos no-newtonianos. Se empleó un sistema de transporte con varios accesorios en los que se hicieron pasar los fluidos de prueba, midiendo el flujo volumétrico y las pérdidas de presión. Los coeficientes de fricción que se obtuvieron para el agua como fluido de referencia fueron entre 0.42 y 25.7, y para las soluciones de sal de sodio de carboximetil celulosa (NaCMC) entre 0.43 y 38.1. Los coeficientes de fricción obtenidos aumentaron con la concentración, lo que permitió obtener una relación potencial entre dicho coeficiente y la concentración de sal para la mayoría de los accesorios y tuberías en que fueron empleados. Las diferencias encontradas al comparar los valores determinados experimentalmente con otros informados en la literatura, se atribuyen al comportamiento reológico del fluido, al circuito de flujo empleado, y al llamado "efecto de influencia mutua" de los accesorios. The objective of the present study was to measure pressure drops to obtain friction coefficients of non-Newtonian fluids. A transport system was employed using various piping transport systems through which test fluids were passed while measuring volumetric flows and pressure drops. The friction coefficients obtained for water as a reference fluid ranged from 0.42 to 25.7, and for solutions containing the sodium salt of carboxymethyl cellulose (NaCMC) were from 0.43 to 38.1. The friction coefficients increased with increases in the concentration, which allowed determination of a potential relation between this coefficient and the concentration of the salt for most of the fittings and type of pipes tested. The differences found when comparing the experimentally obtained values with those reported in the literature were attributed to the rheological behavior of the fluid, the circuit employed in transporting the fluid, and the so-called "mutual influence effect" of the pipe fittings.

This research is directed toward rapid, sensitive, and selective determination of beta- and alpha emitting radionuclides such as 99Tc, 90Sr, and transuranium (TRU) elements in low-activity waste (LAW) processing streams. The overall technical approach is based on automated radiochemical measurement principles. Nuclear waste process streams are particularly challenging due to the complex, high-ionic-strength, caustic brine sample matrix, the presence of interfering radionuclides, and the sometimes variable and uncertain speciation of the radionuclides to be analyzed. As a result, matrix modification, speciation control, and separation chemistries are required for use in automated process analyzers. Significant knowledge gaps exist relative to designing chemistries for such analyzers so that radionuclides can be quantitatively and rapidly separated and analyzed in high ionic strength solutions derived from low-activity waste processing operations. This research is addressing the se knowledge gaps and automated microscale fluid handling techniques will be used to integrate sample modification, chemical separation chemistries, and radiometric detection steps within a single functional process analytical instrument.

The TCPB (Temperature-Controlled Pool Boiling) device is developed to perform pool boiling heat transfer studies by the temperature-controlled technique on Earth and under microgravity conditions aboard the Chinese recovery satellite. Its aim is to investigate the heat transfer in the nucleate and transition pool boiling regimes. This paper describes the design of this device in detail. The preliminary ground experimental results are also presented and analyzed, which show that the technical and scientific expectations can be fulfilled.

In this article we describe a micro pump, which was developed especially for the needs in micro-fluidic total analysis systems (/spl mu/TAS). As this pump is of simple structure, and because it can be manufactured with planar production methods, it is both technically and economically feasible to integrate it as a one-way product into the manufacturing process of micro-fluidic analysis systems. The valves do not have any moving parts, and because of that, they are tolerant to particles in the pumped fluid. This makes them very well suited for the transport of particle-loaded fluids like blood samples. By modifying the valve layout, the pumping rates may be varied between 34 /spl mu/l/min and 55 /spl mu/l/min. In a slightly different valve layout featuring flexibly moving flaps the pumping rate can be increased up to 105 /spl mu/l/min. The counter-pressures achievable are in the range of 892 Pa to 1353 Pa, or ( in the version with flexibly movable sections) up to 3806 Pa.

In this study we introduce two novel concepts for fluid handling in microfluidic systems and show their realization in micromachined test structures: a one-shot micropump and a normally open one-shot valve. Both principles use Expancel/spl reg/ microspheres, which are small spherical plastic particles that, when heated, increase their volume by a factor of about 60. The expansion is irreversible, i.e. when cooled again, the expandable microspheres do not shrink.

Electro-osmotically induced pumping (EOIP) can be used for sample and fluid handling in field-free regions in microfluidic devices. Here, EOIP for fluid handling in field-free regions is combined with electrophoretic separation, resulting in enhanced flexibility in sample handling. The influence of the EOIP-driven sample zone formation on the resulting peak area and separation efficiency was investigated. Increased EOIP voltages resulted in the injection of larger sample zones, as indicated by increased peak areas and decreased separation efficiency.

The slick interior of the pitcher plant has inspired a slippery material possessing self-lubricating, self-cleaning and self-healing properties. The secret is to infuse a porous material with a liquid that repels oils and water. See Letter p.443 Inspired by the insect-eating Nepenthes pitcher plant, which snares its prey on a surface lubricated by a remarkably slippery aqueous secretion, Joanna Aizenberg and colleagues have synthesized omniphobic surfaces that can self-repair and function at high pressures. Their 'slippery liquid-infused porous surfaces' (or SLIPS) exhibit almost perfect slipperiness towards polar, organic and complex liquids. SLIPS function under extreme conditions, are easily constructed from inexpensive materials and can be endowed with other useful characteristics, such as enhanced optical transparency, through the selection of appropriate substrates and lubricants. Ultra-slippery surfaces of this type might find application in biomedical fluid handling, fuel transport, antifouling, anti-icing, optical imaging and elsewhere.

To create a small, portable, fully automated biosensor, a compact means of fluid handling is required. We designed, manufactured, and tested a "fluidics cube" for such a purpose. This cube, made of thermoplastic, contains reservoirs and channels for liquid samples and reagents and operates without the use of any internal valves or meters; it is a passive fluid circuit that relies on pressure relief vents to control fluid movement. We demonstrate the ability of pressure relief vents to control fluid movement and show how to simply manufacture or modify the cube. Combined with the planar array biosensor developed at the Naval Research Laboratory, it brings us one step closer to realizing our goal of a handheld biosensor capable of analyzing multiple samples for multiple analytes.

A comprehensive and quantitative evaluation of the mud mixing, solids control and waste management systems on rigs prior to the commencement of a drilling operation has been shown to dramatically improve operational efficiency and ultimate fluid-related costs. This paper discusses the evaluation process, which includes an audit of the total fluids system, aimed at assuring that the solids control, fluids handling and mixing systems are functioning to specifications and configured properly for the well objectives. The authors will examine in detail the various components of an intensive rig evaluation, which include everything from the condition and configuration of the shakers to the dimension of the mud pits and their fittingness for treating and processing the specific mud volumes required for a given project. In addition, the evaluation includes a safety audit of all areas where fluid engineers will be working, such as the pit room and shaker house. In demonstrating the effectiveness of such an evaluation, the authors will consider specific examples, including audits conducted on newbuilds, rigs undergoing refurbishment and even to improve the solids control and waste management efficiency of units while a well was in progress. The authors will discuss the results of an evaluation of an entire fleet of deepwater rigs with emphasis on the subsequent recommendations. On one deepwater rig in the Gulf of Mexico, the operator saved $48,000 in fluid-related costs when the evaluation revealed that the solids control equipment was not operating at peak efficiencies. Many existing rigs are found to require only a minimum amount of repair or adjustments to show improvements. On most occasions, the evaluation can be used to construct more efficient solids processing and waste management plans.

A modified format for conducting a diffusion immunoassay is described. Polyacrylamide hydrogels containing antibody are used to conduct the assay under non-flow conditions. Fluorescein-labeled biotin and biotin-specific antibody were used as a model system. This assay format shrinks the device area required, reduces the required reagent volumes, and greatly simplifies fluid handling.

We demonstrate the use of dielectrophoresis (DEP) in a programmable microsystem to drive the formation and handling of small (10 to 1000 nL) droplets of sample and reagent on a channel-less, planar reaction surface. DEP-controlled metering and mixing of reagent droplets is shown in a proof-of-principle protein concentration assay. The electronically reconfigurable droplet processor described here is expected to provide functionality for many chemical, biological, and diagnostic applications.

Integrated capillary electrophoresis (ICE) is emerging as a new analytical tool allowing fast, automated, miniaturized and multiplexed assays, thus meeting the needs of the pharmaceutical industry in drug development. The current state-of-the-art of ICE is described with an emphasis on the choice of the support material (glass or polymeric materials), electrokinetic fluid handling, and injection and detection issues. Strategies and chip designs for pre- or post-column derivatization, DNA sequencing, on-line PCR analysis, on-chip enzymatic sample digestion, fraction isolation, and immunoassays are presented. The review concludes with a brief outlook.

For fluid handling in analytical chemistry, the batch process is the typical way. This paper raises the question, whether this is still the best on the chip scale and briefly discusses a few examples of continuous-flow modules.

Wound healing is promoted by dressings that maintain a moist environment. Specifically, hydrocolloid dressings allow excess fluid to escape without permitting wound desiccation. However, the fluid handling capacity of hydrocolloid dressings depends on many factors such as the physicochemical properties of the gel formulation, and the design of the dressing. We measured the moisture uptake kinetics of different hydrocolloid dressings by placing the gel side of a sample in contact with water. The time evolution of the thickness was measured by means of a video camera linked to a computer. The theory of Tanaka and Fillmore (1979) was used to predict the kinetics of uniaxial swelling of a cylindrical gel sample. The model allows to associate to an experimental curve a total thickness increase hf-h0 (where hf and h0 are respectively the final and initial thickness) and a characteristic time tau. The model also relates hf-h0 and tau to the physiochemical composition of the dressing, and to the initial thickness h0. The influence of h0 is discussed by means of experiments performed on dressings with different initial thickness.

Chromatography-based techniques for automating trace component determination in biological matrices are examined. Once samples are brought into solution or extracted, a range of fluid handling systems may be applied to automate most analyses. However, extraction remains a limiting step and the development costs and time required to automate any method successfully must be carefully considered. These and other factors which will influence the decision to automate any analytical method are explored and the problems of trace analysis discussed. Methods based on solid-phase extraction, dialysis and column switching approaches are evaluated in detail and interesting approaches described.

A fluid handling and injection system for a micro total chemical analysis system (µTAS) for monitoring water conditions is presented in this paper. In general a µTAS is obtained by the integration of the following components: a) a fluid handling and injection system; b) a selective sensor to detect and measure the concentration of chemical species; c) an electronic unit to control pumps, valves and sensors. The fluid injection system described in this paper has been designed and realized in order to obtain optimal hydraulic behaviour, to simplify fabrication and to achieve good reliability. A basic configuration of the proposed µTAS comprises: micropumps, active microvalves, flow channels and conduits for reactors. The above components can be combined so as to obtain different configurations intended for sophisticated analysis processes.

Students often find models useful in learning or reviewing physiological concepts. As a result, we have developed a physical model of the gastrointestinal tract, which is used in the GI sections of our medical and graduate physiology courses to demonstrate ingested, secreted, reabsorbed, and

Calorimetry is the science of measuring heat. For more than 200 years now, calorimetry has advanced and various types of calorimeters have been developed for diverse applications. The development of microfabrication and microfluidics led to the advent of chip calorimeters, miniaturized calorimeters built and integrated as chips. Chip calorimeters, as label- free biosensors, have many advantages due to their small sample volume and high-throughput capability. In this review, techniques for realizing chip calorimeters are discussed in terms of their major functional components: insulation, fluid handling, and thermometry. Recent trends in the development of chip calorimeters are also discussed, along with several application areas. New fabrication techniques can provide higher sensitivity and easier, more reliable sample handling for chip calorimeters, which would enable new application areas, such as the study of single cell metabolism.

Effective pathogen detection is an essential prerequisite for the prevention and treatment of infectious diseases. Despite recent advances in biosensors, infectious diseases remain a major cause of illnesses and mortality throughout the world. For instance in developing countries, infectious diseases account for over half of the mortality rate. Pathogen detection platforms provide a fundamental tool in different fields including clinical diagnostics, pathology, drug discovery, clinical research, disease outbreaks, and food safety. Microfluidic lab-on-a-chip (LOC) devices offer many advantages for pathogen detection such as miniaturization, small sample volume, portability, rapid detection time and point-of-care diagnosis. This review paper outlines recent microfluidic based devices and LOC design strategies for pathogen detection with the main focus on the integration of different techniques that led to the development of sample-to-result devices. Several examples of recently developed devices are presented along with respective advantages and limitations of each design. Progresses made in biomarkers, sample preparation, amplification and fluid handling techniques using microfluidic platforms are also covered and strategies for multiplexing and high-throughput analysis, as well as point-of-care diagnosis, are discussed.

WHEN INSECTS land on the walls of Nepenthes pitcher plants, they soon meet their doom, thanks to a surface that causes them to slip into the digestive juices at the plant bloom’s bottom. By mimicking the pitcher plant’s slick means of gathering a meal, Joanna Aizenberg and colleagues at Harvard University have created an omniphobic material that repels simple liquids such as water and hydrocarbons, complex fluids such as crude oil and blood, and even solids. Ants, for example, can’t scale its slippery surface ( Nature, DOI: 10.1038/nature10447). “We envision the use of these surfaces for biomedical fluid handling, for fuel transport, and as a surface that repels ice and can therefore be used to reduce energy in refrigeration,” Aizenberg tells C&EN. The so-called slippery liquid-infused porous surfaces, or SLIPS, are self-lubricating, self-cleaning, and self-healing, and they can be made transparent. “We believe these features make the material an ideal candidate not only ...

Research activities throughout the world concerning micro fluid-handling are reviewed. Pumps and ink-jet heads, valves and flow sensors are discussed. Many research groups are moving into this emerging field, usually, aiming at the development of complete systems for chemical analysis or medicine delivery. Some comments on future trends and opportunities are given. >