Fundamentals and Applications of Microfluidics
This forward-looking book explains how to take advantage of the performance benefits of microfluidics and serves as a reference for technology and applications in this area.
TABLE OF CONTENTS Fundamentals and Applications of Microfluidics
Chapter 9: Microfluidics for Life Sciences and Chemistry
Microfluidics has emerged as a new approach for improving performance and functionality of biochemical and medical analysis. Miniaturization and new effects in microscale promise completely new system solutions in these fields. Dimension reduction results in faster processes and less reagent consumption. The small size also allows parallel processing, in which more compounds can be produced and analyzed. In addition, recent developments in biotechnology, such as mapping the human genome, require new supporting tools and products.
In this chapter, design considerations and examples are given for microfluidic devices in life sciences and chemistry such as microfilters, microneedles, micromixers, microreactors, microdispensers, and microseparators.
9.1 Microfilters
Microfilters have two unique functions: filtration and collection. Microfilters separate particles from a fluid for applications, which require a clean fluid for further processes. Microfilters are used for washing out waste products of the precedent process. In packed-bed microreactors, filters are used for keeping beads in reaction chambers.
In other applications, the filtered particles are of interest. Microfilters separate particles from the mean flow and send them to further processing stages. Based on their fabrication technology and, consequently, their typical pore size, microfilters are categorized as membrane filters and gap filters.
The basic structure of the first type is a thin membrane that contains filtering pores. These pores are etched through the membrane with a mask defined by photolithography. Because of the limited resolution of the lithography process, membrane filters have relatively large pores on the order of microns.
Gap filters use the gap between two structural...
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