Mechanics for Fluidics and Bio-Devices

In this chapter, we firstly present mechanical elements which are essential components of Lab-On-Chip devices as they can provide sensing, mixing, pumping and controlled delivery of small fluidic volumes. Microvalves, crucial for the on-chip implementation of complex fluidic patterns, are discussed first. Micropumps, typically built as a collection of microvalves operated in sequence, are subsequently described. Finally, a short overview of nanomechanical biosensors, which have demonstrated great capabilities in label-free sensing applications, is provided. Particular attention will be paid to mechanical sensing in liquids, focusing on limitations and novel techniques. In a second part, we will focus on concentrating, focusing, trapping, sorting and single cell biomechanical characterization which are critical steps in various biomedical applications such as diagnostics, therapeutics, drug screening and cell biology. Microfluidic technologies propose attractive engineered microenvironments for the manipulation and the study of cellular mechanics compatible with high throughput. The different approaches available to act on cells and perform mechanical phenotyping in microsystems are detailed and discussed.