Structured Material Generation and Chemical Handling Advancements inMicrofluidic Platforms.

[摘要] Microfluidic technology was developed, in part, to miniaturize chemical analysis techniques.However, difficulties remain in functionality. Several microfluidic techniques were developed to enhance microfluidic functionality and study phenomena that occur in microfluidic systems. Handling nanoliter chemical volumes in microchannels was addressed by integrating a permeable polymer wall separating nanoliter droplets, where droplet contents could actively be manipulated by diffusion.Droplets were actively manipulated through a user-defined chemical flow to deliver solvents, reagents for reactions, perform separations and dissolve solid precipitate.Transport occurring in these systems was also analyzed and characterized, and transport rates from hundreds of fL/s to pL/s were achieved.Microscale separations of double-stranded DNA during polyacrylamide gel electrophoresis were studied in a microchannel with confocal laser scanning microscopy (CLSM), allowing DNA migration to be imaged at a plane normal to its migration direction.dsDNA displays a net transverse migration and concentrates at the top and bottom of the polyacrylamide gel.This phenomena is analyzed and explained with both experimental results and simulations.An imhonogenous pore size is attributed to be responsible for the observed migration. Using a three-dimensional microfabrication method, both 10 µm particles and yeast cells were positioned on microfabricated 5 µm through-holes using convective flow.This method is shown to be rapid to create accurate two dimensional patterns in around 2 seconds, and was subsequently used to fuse microparticle clusters and to cuture cells from a predefined two-dimensional pattern. The device was further expanded to be able to precisely position two particle types by independently controlling drains. Finally, the properties of miniaturized laminar co-flows were investigated.Through-holes were used to create an alternating co-flow structure where the number of co-flowing streams could be scaled up to 64, 750 nm streams.Fluidic effects that arise and can interfere with the quality of co-flows were investigated and conclusions were drawn that are applicable to future designs.Effects that were investigated include stream uniformity caused by non-uniform path lengths, diffusion, and Dean flow caused by quickly constricting flows at high Dean numbers.

[发布机构] University of Michigan

[效力级别] Two Dimensional Particle Arrays

[关键词] Microfluidics;Two Dimensional Particle Arrays;Microchannel Electrophoresis;Laminar Coflow;Nanoliter Handling;Chemical Engineering;Engineering;Chemical Engineering