Miniaturized total chemical analysis systems: A novel concept for chemical sensing
TL;DR: In this paper, a modular construction of a miniaturized "total chemical analysis system" is proposed, and theoretical performances of such systems based on flow injection analysis, chromatography and electrophoresis are compared with those of existing chemical sensors and analysis systems.
Abstract: Following the trend towards smaller channel inner diameter for better separation performance and shorter channel length for shorter transport time, a modular construction of a miniaturized 'total chemical analysis system' is proposed. The theoretical performances of such systems based on flow injection analysis, chromatography and electrophoresis, are compared with those of existing chemical sensors and analysis systems.
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TL;DR: Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes to devices that handle aqueous solutions.
Abstract: Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft-lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics-derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.
3,344 citations
TL;DR: In this article, the physical mechanisms and the main experimental parameters involved in femtosecond laser micromachining of transparent materials, and important emerging applications of the technology are described.
Abstract: Femtosecond laser micromachining can be used either to remove materials or to change a material's properties, and can be applied to both absorptive and transparent substances. Over the past decade, this technique has been used in a broad range of applications, from waveguide fabrication to cell ablation. This review describes the physical mechanisms and the main experimental parameters involved in the femtosecond laser micromachining of transparent materials, and important emerging applications of the technology. Interactions between laser and matter are fascinating and have found a wide range of applications. This article gives an overview of the fundamental physical mechanisms in the processing of transparent materials using ultrafast lasers, as well as important emerging applications of the technology.
2,533 citations
Cites methods from "Miniaturized total chemical analysi..."
...Microfluidic devices The fast automated and parallel processing of small quantities of fluid requires an increasing miniaturization of chemical and biological set-up...
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TL;DR: The progress made by lab-on-a-chip microtechnologies in recent years is analyzed, and the clinical and research areas in which they have made the greatest impact are discussed.
Abstract: Microfluidics, a technology characterized by the engineered manipulation of fluids at the submillimetre scale, has shown considerable promise for improving diagnostics and biology research. Certain properties of microfluidic technologies, such as rapid sample processing and the precise control of fluids in an assay, have made them attractive candidates to replace traditional experimental approaches. Here we analyse the progress made by lab-on-a-chip microtechnologies in recent years, and discuss the clinical and research areas in which they have made the greatest impact. We also suggest directions that biologists, engineers and clinicians can take to help this technology live up to its potential.
2,276 citations
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TL;DR: Highly integrated microdevices show great promise for basic biomedical and pharmaceutical research, and robust and portable point-of-care devices could be used in clinical settings, in both the developed and the developing world.
Abstract: Microsystems create new opportunities for the spatial and temporal control of cell growth and stimuli by combining surfaces that mimic complex biochemistries and geometries of the extracellular matrix with microfluidic channels that regulate transport of fluids and soluble factors. Further integration with bioanalytic microsystems results in multifunctional platforms for basic biological insights into cells and tissues, as well as for cell-based sensors with biochemical, biomedical and environmental functions. Highly integrated microdevices show great promise for basic biomedical and pharmaceutical research, and robust and portable point-of-care devices could be used in clinical settings, in both the developed and the developing world.
2,082 citations
Cites background from "Miniaturized total chemical analysi..."
...Much cell-based microsystem research takes place under a 'lab-on-a-chip' or 'micro-total-analysis-system' (µTAS) framework that seeks to create microsystems incorporating several steps of an assay into a single syste...
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TL;DR: In this article, the authors demonstrated a miniaturized system for sample handling and separation using electrophoresis-based separations of amino acids with up to 75,000 theoretical plates in about 15 seconds.
Abstract: Micromachining technology was used to prepare chemical analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic separation to distinguish sample components. Capillaries 1 to 10 centimeters long etched in the glass (cross section, 10 micrometers by 30 micrometers) allow for capillary electrophoresis-based separations of amino acids with up to 75,000 theoretical plates in about 15 seconds, and separations of about 600 plates can be effected within 4 seconds. Sample treatment steps within a manifold of intersecting capillaries were demonstrated for a simple sample dilution process. Manipulation of the applied voltages controlled the directions of fluid flow within the manifold. The principles demonstrated in this study can be used to develop a miniaturized system for sample handling and separation with no moving parts.
1,815 citations
References
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TL;DR: In this paper, the effect of sample volume, tube length, tube diameter, peak height and sampling rate on the determination of phosphorus in acidic plant digests was investigated, and optimal conditions for the flow injection method were described.
1,554 citations
TL;DR: In this article, a miniature gas analysis system based on the principles of gas chromatography (GC) has been built in silicon using photolithography and chemical etching techniques, which allows size reductions of nearly three orders of magnitude compared to conventional laboratory instruments.
Abstract: A miniature gas analysis system has been built based on the principles of gas chromatography (GC). The major components are fabricated in silicon using photolithography and chemical etching techniques, which allows size reductions of nearly three orders of magnitude compared to conventional laboratory instruments. The chromatography system consists of a sample injection valve and a 1.5-m-long separating capillary column, which are fabricated on a substrate silicon wafer. The output thermal conductivity detector is separately batch fabricated and integrably mounted on the substrate wafer. The theory of gas chromatography has been used to optimize the performance of the sensor so that separations of gaseous hydrocarbon mixtures are performed in less than 10 s. The system is expected to find application in the areas of portable ambient air quality monitors, implanted biological experiments, and planetary probes.
1,414 citations
TL;DR: This paper presents a meta-review of the Flow--Injection Literature and discusses theoretical Aspects of FIA Techniques, components of An FIA Apparatus, and Experimental Techniques and FIA Exercises.
Abstract: Introduction. Principles. Theoretical Aspects of FIA Techniques. Components of An FIA Apparatus. Experimental Techniques and FIA Exercises. Review of the Flow--Injection Literature. Flow Injection Analysis Now and in the Future. List of FIA References. Appendix. Index.
1,367 citations
TL;DR: In this article, the design and realization of two pumps based on micromachining of silicon are described, which are of the reciprocating displacement type, comprise one or two pump chambers, a thin glass pump membrane actuated by a piezoelectric disc and passive silicon check valves to direct the flow.
706 citations
TL;DR: In this article, a silicon chip with an open-tubular column and a conductometric detector, a chip holder and a pressure pulse driven injector using a conventional liquid chromatography pump and valves is presented, which has theoretical separation efficiencies of 8000 and 25 000 plates in 1 and 5 min, respectively.
Abstract: A novel concept of high pressure liquid chromatography is presented, involving a silicon chip with an open-tubular column and a conductometric detector, a chip holder and a pressure pulse driven injector using a conventional liquid chromatography pump and valves. The design and optimization of the chromatograph and the chip are discussed. A 5 × 5 mm chip containing an open-tubular column of 6 μm × 2 μm × 15 cm was fabricated, which has theoretical separation efficiencies of 8000 and 25 000 plates in 1 and 5 min, respectively. The total column volume is 1.5 nanoliter and the detection cell volume 1.2 picoliter.
368 citations