Microfluidic devices solid-phase extraction

Keywords Continuous flow PCR DNA analysis DNA microarrays Genetic analysis Integrated microsystems Microcapillary electrophoresis Microfluidics Micro-PCR devices Solid-phase extraction... 

Yu, C., Davey, M. H., Svec, F, and Frechet, J. M. (2001). Monolithic porous polymer for on-chip solid-phase extraction and preconcentration prepared by photoinitiated in situ polymerization within a microfluidic device. Anal. Chem. 73, 5088-5096. 

Ramsey, J. D. and G. E. Collins. Integrated microfluidic device for solid-phase extraction coupled to micellar electrokinetic chromatography separation. Anal. Chem. 77, 6664-6670 (2005). 

In addition to electrophoresis-based collection of DNA in microchannels (see Section 7.7.3), adsorbents have been used to collect and purify DNA. In these cases, microchannels are generally used because of the small quantity of material requiring collection. Using solid phase extraction, sorbent particles of nano- and micro-silica and micro-sized octadecylsilica were immobilized using sol-gel chemistry to hU the microchannels of the microfluidic device [194]. DNA as well as several organic compoimds were evaluated for adsorption and desorption. They showed excellent adsorption, but poor recovery because they were difficult to extract. 

In contrast, the mode of operation of a number of other modules in microfluidic devices, such as reactors, solid-phase extraction, and separation units require interactions of molecules in solution with functionalities attached to a solid support. Obviously, this support can itself be the channel wall but, in this case, the overall surface-to-volume ratio is very small. This ratio can be increased by filling the channel with a solid phase, and the monolithic materials represent one of the options to fill the channel with a suitable stationary phase. 

Sample Preconcentration/Solid-Phase Extraction. A microfluidic device with an external EOF... 

Recently, Wang et al. [9] developed a microfluidic device that could perform electroki-netic sample fractionation and solid-phase extraction simultaneously. Effluents from a fractionation were subsequently delivered into an array of 36 collection channels containing butyl methacrylate-based monolithic polymer for sohd-phase extraction. Tightly focused sample zones of protein sample could be obtained after electroki-netic fractionation in each of the 36-channel polymer beds without observed cross contamination, indicating great promise for automated operation of these devices in proteomics research. 

Yu C et al (2001) Monolithic Porous Polymer for On-Chip Solid-Phase Extraction and Preconcentration Prepared by Photoinitiated in Situ Polymerization within a Microfluidic Device. Anal Chem 73 5088-5096... 

Quake and coworkers [16] developed a PDMS microfluidic device (shown in Eig. 4c) for nucleic acid purification from a small number of bacterial or mammalian cells. This multilayer device contained fluidic channels and a system of membrane-actuated pneumatic valves and pumps, which enabled precise control of buffers, lysis agents and cell solution, and also allowed for parallel processing. Bacterial cells, dilution buffer and lysis buffer are first introduced into the chip and then transferred into the rotary mixer. Once mixed, the lysate is flushed over a DNA affinity column and drained. The DNA is recovered from the chip with an elution buffer for further analysis. We note that this is the only microfluidic chemical C3flome-try device to use a separation method other than solution-phase electrophoresis (i. e., solid phase extraction). 

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