Polydimethylsiloxane (PDMS) has attracted huge interest as the soft material for microchannel fabrication, due to its high biocompatibility, durability and low cost. The rheological properties of the fluid and the deformable properties of PDMS substrate have imposed significant impacts on the fluid flow in the microchannel, therefore it is of critically importance to develop sensing methods for the accurate flow rate monitoring and the flow-induced pressure measurement without disturbing the fluid flow in the microchannel. This paper presents an embedded and miniaturized pressure sensor based on the Fiber Bragg Grating (FBG) technique for the measurement of both flow rate and flow-induced pressure in PDMS-based microchannel. This method has demonstrated a pressure sensitivity of 0.06 p.m./Pa and the Limit of Detection (LoD) for pressure is 19.5 Pa. The linearity between flow-induced pressure and flow rate in PDMS-based microchannel is about 4.86 Pa(ml/h) based on simulation results and is within the range between 4.33 Pa(ml/h) and 6.67 Pa(ml/h) obtained from experimental results. The LoD of flow rate using this method is within the range between 2.9 ml/h and 4.5 ml/h. The random instability induced by the operation of the reconnection of syringe back to the liquid flow system was identified and the calibration of this instability is also presented in this paper. Using this method, the pressure and flow rate within PDMS-based microchannel can be monitored with high reliability and high sensitivity, and this will benefit the application of PDMS-based microfluidics in areas that require highly precise control in flow conditions, e.g. biosensing, cell culture, and drug delivery.

中文翻译：

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使用光纤布拉格光栅技术在聚二甲基硅氧烷基微通道中实时嵌入压力和流量传感器

聚二甲基硅氧烷（PDMS）作为微通道制造的软材料，由于其高生物相容性、耐用性和低成本而引起了极大的兴趣。流体的流变特性和PDMS基底的变形特性对微通道中的流体流动产生了显着的影响，因此开发精确的流量监测和流引起的压力测量而不受干扰的传感方法至关重要微通道中的流体流动。本文提出了一种基于光纤布拉格光栅 (FBG) 技术的嵌入式微型压力传感器，用于测量基于 PDMS 的微通道中的流速和流动引起的压力。该方法的压力灵敏度为 0.06 pm/Pa，压力检测限 (LoD) 为 19.5 Pa。基于 PDMS 的微通道中流动引起的压力和流速之间的线性约为 4.86 Pa(ml/h)基于模拟结果，在根据实验结果获得的 4.33 Pa(ml/h) 和 6.67 Pa(ml/h) 之间的范围内。使用此方法的流速 LoD 在 2.9 ml/h 至 4.5 ml/h 范围内。识别了由注射器重新连接回液流系统的操作引起的随机不稳定性，并且本文还提出了这种不稳定性的校准。利用该方法，可以高可靠性和高灵敏度地监测基于PDMS的微通道内的压力和流速，这将有利于基于PDMS的微流控在需要高精度流动条件控制的领域中的应用，例如生物传感、细胞文化和药物输送。