Microfluidics cards

Recently (2004), Applied Biosystems have introduced microfluidics cards or low-density gene expression arrays. These cards follow the main Taqman principles, but are based on a 384-well plate design. Therefore, multiple samples and genes can be monitored, quantitatively, at the same time. Maley et al. (2004) have also reported the use of a multiplexed Taqman model for high throughput screening applications. 

For catalyst testing, conventional small tubular reactors are commonly employed today [2]. However, although the reactors are small, this is not the case for their environment. Large panels of complex fluidic handling manifolds, containment vessels, and extended analytical equipment encompass the tube reactors. Detection is often the bottleneck, since it is still performed in a serial fashion. To overcome this situation, there is the vision, ultimately, to develop PC-card-sized chip systems with integrated microfluidic, sensor, control, and reaction components [2]. The advantages are less space, reduced waste, and fewer utilities. 

As pointed out earlier, microfluidic systems have a wide range of applications, e.g. heat exchange systems for electronic devices [28-31], medical diagnostic and analytical chemical applications [69, 70], and precision dilution systems with minimal dead volume for gas chromatography [71]. More may be anticipated as the technology matures. Current research at many laboratories has shown the need to provide flow control at extremely low levels for sensor-controlled implanted drug delivery systems [72] and portable diagnostic cards for polymerase chain reaction analysis [73]. 

Figure 10.13 The Quickiab device and diagnostic card on the right, both the device and card are uncovered revealing the inner components of the handheld reader and the microfluidics on the chip (Photographs Courtesy of Siemens AC).

Kokoris, M., Nabavi, M., Lancaster, C., Clemmens, J., Maloney, R, Capadanno, J., Gerdes, J., and Battrell, C. R, Rare cancer cell analyzer for whole blood applications Automated nucleic acid puriflcation in a microfluidic disposable card, Methods, 37, 114, 2005. 

Figure 76.6 Photograph of the assembled prototype including a microfluidic chip and a mobile phone SIM card for comparison. Photograph of the assembled prototype (a). Arrow indicates the microfluidic device. For comparison, a mobile phone SIM card (b) along the microfluidic chip (c). Reproduced with permission from Ref [168]. The Royal Society of Chemistry...

Stevens, D.Y., Petri, C.R., Osborn, J.L., Spicar-Mihalic, P., McKenzie, K.G., Yager, P, 2008. Enabling a microfluidic immunoassay for the developing world by integration of on-card dry reagent storage. Lab. Chip 8, 2038-2045. http //dx.doi.org/10.1039/B811158H. 

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