Pressure measurement methods in microchannels: advances and applications

With the continuous development of the lab-on-a-chip studies, pressure measurements in microchannels have become the guarantee of the precise control and regulation of trace fluids using microfluidics and caused more research attention. In this review, we first present the basic principles and structures of various pressure measurement methods in microchannels, including the following: (i) membrane or diaphragm-based methods; (ii) membrane-free in-situ methods; (iii) membrane-free side-channel methods; and (iv) other methods. We then illustrate the key applications of these methods in biology, medicine, microfluidic chips, and fluid mechanics. Finally, we prospect the future developments of these methods, which can lead to an unprecedented capability to develop more novel designs of pressure sensors and further applications. We aim to provide a deeper fundamental understanding of the mechanisms of these methods, which could be both a reference for pressure measurement method researchers and a resource for those outside this field who wish to identify the most suitable pressure sensor for a particular application.