Microfabricated structures for cell characterization, separation and culture

Eukaryotic cells have all fundamental functions of life, such as metabolism, excitability, locomotion, and reproduction. Biotechnology aims to effectively use these cellular functions for artificial objectives by controlling intraand intercellular biophysical and biochemical processes including gene expression. However, techniques actually used or usable are very restricted by high variability of cell natures and also fragility of cells with artificial treatments. Technical difficulties also arise from micrometer dimensions of cells. Many researchers would well recognize that micromachining has most useful applications in biotechnology and related fields. In such applications, however, another difficulty appears to exist for engineering researchers to know real needs or requests for microdevices and conditions for their use in the cell technology processes. Any misdesign should lead to mismatch to other procedures and final uselessness. We report here a successful use of micromachined channel arrays in studies of flow properties of blood cells or, more widely, in characterization of cells by their mechanical properties such as deformability, adhesiveness, and motility and an attempt to further use them in separation of cells according to differences in these characters. Micropit arrays are also described for use in cell culture, which now becomes a basic process of cell science and biotechnology.