A disposable microfluidic flow sensor with a reusable sensing substrate
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2019 Elsevier B.V. In many biological, medical and pharmaceutical applications, disposable flow sensors are highly desired to prevent biological contamination. However, due to their high cost, conventional microfluidic flow sensors are difficult to be used as disposable. This paper introduces a disposable microfluidic flow sensor (disposable-FSensor) consisting of a disposable microchannel superstrate and reusable sensing substrate, which can be assembled and disassembled simply by vacuum pressure. Because the disposable microchannel superstrate is fabricated easily and cheaply using a silicone-coated release polymer thin film, it can be replaced after a single use, while the sensing substrate can be reused continuously. Experimental results show that the sensitivity, reproducibility, response time, long-term stability, resolution, and accuracy of the disposable-FSensor are comparable to those of commercial microfluidic flow sensors. One of the key advantages of the disposable-FSensor is that the measurable flow rate range can be adjusted very broadly, from 10 to 650 L/min, by simply replacing only the disposable microchannel that has different bypass channel design, without having to change the sensing substrate. To demonstrate the usefulness of the disposable-FSensor for biological, medical and pharmaceutical applications, the developed sensor was used to control the flow rates of a droplet generator, with the generated droplets having variations in diameter and volume of less than 1.25% and 4%, respectively. In summary, we report that the disposable-FSensor is reproducible and accurate for various applications at low cost as well as resistant to biological contamination, in contrast to conventional flow sensors.