Chip detection

Warrington, B., Wong, S., The design of a continuous flow combinatorial screening micro-reactor system with on-chip detection, in van den Berg, A.,... 

Fragmented, biotinylated RNA prepared in this manner was hybridized to the array and the signal developed using streptavidin-R-phycoerytherin. A confocal laser scanner was used for detection. The researchers estimated that they could detect two transcripts per cell based upon labeling efficiency and an estimated 4% mRNA content in total bacterial RNA. Thus, chip detection of labeled transcripts was found to be more sensitive than detection by Northern blot. Specific genes (e.g., basal levels of cinA) undetectable on Northern blots were quantifiable on the microarray. In addition, it was... 

Chapter 13, Lab-on-a-Chip Detection of Explosives, describes one particular technology that has been successfully developed in a very small size. It too thus becomes representative of the possibilities that are offered by sensor systems of this genre. 

Micro- and nano-beads have become a major tool in analytical chemistry sciences. On one hand, micrometer size beads were developed with a very large range of properties such as magnetic and/or fluorescent beads, having different surface functional groups for coupling chemistry or physicochemical properties. On the other hand, few nanometer size particles were shown to be potential powerful labels for on chip detection of DNA strands. 

Easley et al. showed integrated DNA purification, PCR, electrophoretic separation and detection of pathogens in less than 30 min [116]. The assay was performed on a pressure driven four layer glass/PDMS chip with elastomeric valves. Temperature cycling for PCR was achieved by IR radiation. Only the sample lysis step was not integrated in the microfluidic chip. Detection of Bacillus anthracis from infected mice and Bordetella pertussis from a clinical sample was successfully demonstrated. 

As consequence of implementation of parallelization in microfluidic cell culture chips, detection of biologically relevant cellular parameters imposes further requirements on the development of the applied detection techniques. Using available motorized microscope stages, time-lapse fluorescence microscopy is a widely applied technique in monitoring cellular responses. Alternatively, fluorescent plate readers facilitate real-time monitoring in highly parallelized systems (readouts for 1,536 well microtiter plate format). 

On-chip detection firstly relied on optical techniques, such as ultraviolet (UV) absorbance, fluorescence or laser-induced fluorescence (LIF).1,2 The latter technique in particular has a sensitivity in the (sub)micromolar range which is suitable for microfluidic applications. Besides optical techniques, electrical-based techniques are also widely used for on-chip detection due to their sensitivity, e.g. detection based on conductivity,3 electrochemistry,4 electrochemiluminescence,5 etc. The main advantage of these techniques is that they... 

Coupling a microfluidic or microfabricated system to MS appears to be fruitful for both the detection on the chip (microchip point of view) and for the MS analysis (MS point of view). On the one hand, MS is a powerful technique for on-chip detection due to its sensitivity and the amount of information it provides on the sample on the other hand, by using microfluidics prior to the MS analysis, new opportunities for the field of MS are created as it provides better MS capabilities compared to conventional sample preparation techniques. 

Abstract Optical detection continues to dominate detection methods in microfluidics due to its noninvasive nature, easy coupling, rapid response, and high sensitivity. In this review, we summarize two aspects of recent developments in optical detection methods on microfluidic chips. The first aspect is free-space (off-chip) detection on the microchip, in which the conventional absorption, fluorescence, chemiluminescence, surface plasmon resonance, and surface enhanced Raman spectroscopies are involved. The second aspect is the optofluidic (inside-chip) detection. Various miniaturized optical components integrated on the microfluidic chip, such as waveguide, microlens, laser, and detectors are outlined. 

Section IV then tackles the most recent trend in analytical instrumentation, which is miniaturisation and the drive to create lab-on-a-chip devices. In this section, 1 discuss the development of chip-based technologies and the challenges associated with this such as pumping fluids on the microscale, fitting components onto a chip, detection strategies and how processes such as mixing are so different in the microworld when compared to the macroworld. 

With the miniaturization enabled by the use of nanostructures and laboratory-on-a-chip, detection or identification devices may easily fit onto small unattended airborne vehicles. A suspect cloud could be probed by flying the unattended airborne vehicle through it or collecting physical samples from the site. In the near term, there will be enough uncertainty in the identification such that a high-regret decision should be based on laboratory confirmation of the field measurement. The same miniaturization may enable small, low power, and easy-to-obscure unattended ground stations that could serve as remote site detection or identification stations. ... 

Sarma, H., 2003. Metal nanoparticles applications in molecular nanotechnology and DNA chip detection. J. Biomol. Struct. Dyn., 17—21. 

On the other hand, spectroscopic detection methods, such as laser-induced fluorescence, UV/Vis absorption, chemiluminescence, and thermal lens microscopy, have been used for on-chip detection. Among these methods, the fluorescence detection method has been most widely used because of its high sensitivity and low detection limits for biologically relevant species. However, the fluorescence detection technique has some disadvantages. Many chemical... 

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