Micromachined Flow Sensors in Biomedical Applications

Abstract

Application fields of micromachined devices are growing very rapidly due to the continuous improvement of three dimensional technologies of micro-fabrication. In particular, applications of micromachined sensors to monitor gas and liquid flows hold immense potential because of their valuable characteristics (e.g., low energy consumption, relatively good accuracy, the ability to measure very small flow, and small size). Moreover, the feedback provided by integrating microflow sensors to micro mass flow controllers is essential to deliver accurately set target small flows. This paper is a review of some application areas in the biomedical field of micromachined flow sensors, such as blood flow, respiratory monitoring, and drug delivery among others. Particular attention is dedicated to the description of the measurement principles utilized in early and current research. Finally, some observations about characteristics and issues of these devices are also reported.

Pushing the Limits of Electrical Detection of Ultralow Flows in Nanofluidic Channels

“…Microfabricated flow sensors are used in a wide range of commercial and research applications, their importance being reflected in the vast number of existing sensors and measurement concepts [1,2]. Also in nanofluidic systems, the flow rate is a desirable property to quantify, e.g., when measuring liquid slip or investigating the transport of macromolecules through nanochannels [3].…”

Analytical studies on amplitude change enhancement in coupled aluminium nitride coated single crystal silicon oscillator pair applicable to ultra‐sensitive resonating microfluidic flowmeters

“…In the case of 0.1 < R e < 10, the relation between the drag coefficient of C D and the Reynolds number can be written as (5), and the acting pressure P in Fig. 3 as a function of the relative flow velocity V can be further simplified as (6).…”

Mode localization in coupled AlN/SCS cantilevers for highly sensitive resonating flow meter

“…Based on the working principles, the micro-machined or MEMS flow sensors can be distinguished into two groups [5]. The first group contains flow sensors based on heat exchange, named "thermal flow sensors"; while all other flow meters based on different working principles rather than thermal exchange, are thus named as "non-thermal flow sensors", which are also divided into several subgroups depending on the principle of measurement used like cantilever flow sensors, differential pressure-based flow sensors, resonating flow sensors, and laser Doppler flowmeters.…”